path: root/src/lib/ffmpeg/avformat.pas

(*
 * copyright (c) 2001 Fabrice Bellard
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *)

(*
 * This is a part of Pascal porting of ffmpeg.
 * - Originally by Victor Zinetz for Delphi and Free Pascal on Windows.
 * - For Mac OS X, some modifications were made by The Creative CAT, denoted as CAT
 *   in the source codes.
 * - Changes and updates by the UltraStar Deluxe Team
 *)

(*
 * Conversion of libavformat/avformat.h
 * Min. version: 50.5.0 , revision  6577, Sat Oct  7 15:30:46 2006 UTC
 * Max. version: 52.63.0, revision 23179, Wed May 19 19:17:00 2010 CET 
 *)

unit avformat;

{$IFDEF FPC}
  {$MODE DELPHI }
  {$PACKENUM 4}    (* use 4-byte enums *)
  {$PACKRECORDS C} (* C/C++-compatible record packing *)
{$ELSE}
  {$MINENUMSIZE 4} (* use 4-byte enums *)
{$ENDIF}

{$I switches.inc}  (* for the HasInline define *)

{$IFDEF DARWIN}
  {$linklib libavformat}
{$ENDIF}

interface

uses
  ctypes,
  avcodec,
  avutil,
  avio,
  rational,
  SysUtils,
  UConfig;

const
  (*
   * IMPORTANT: The official FFmpeg C headers change very quickly. Often some
   * of the data structures are changed so that they become incompatible with
   * older header files. The Pascal headers have to be adjusted to those changes,
   * otherwise the application might crash randomly or strange bugs (not
   * necessarily related to video or audio due to buffer overflows etc.) might
   * occur.
   *
   * In the past users reported problems with USDX that took hours to fix and
   * the problem was an unsupported version of FFmpeg. So we decided to disable
   * support for future versions of FFmpeg until the headers are revised by us
   * for that version as they otherwise most probably will break USDX.
   *
   * If the headers do not yet support your FFmpeg version you may want to
   * adjust the max. version numbers manually but please note: it may work but
   * in many cases it does not. The USDX team does NOT PROVIDE ANY SUPPORT
   * for the game if the MAX. VERSION WAS CHANGED.
   *
   * The only safe way to support new versions of FFmpeg is to add the changes
   * of the FFmpeg git repository C headers to the Pascal headers.
   * You can accelerate this process by posting a patch with the git changes
   * translated to Pascal to our bug tracker (please join our IRC chat before
   * you start working on it). Simply adjusting the max. versions is NOT a valid
   * fix. 
   *)
  (* Max. supported version by this header *)
  LIBAVFORMAT_MAX_VERSION_MAJOR   = 52;
  LIBAVFORMAT_MAX_VERSION_MINOR   = 63;
  LIBAVFORMAT_MAX_VERSION_RELEASE = 0;
  LIBAVFORMAT_MAX_VERSION = (LIBAVFORMAT_MAX_VERSION_MAJOR * VERSION_MAJOR) +
                            (LIBAVFORMAT_MAX_VERSION_MINOR * VERSION_MINOR) +
                            (LIBAVFORMAT_MAX_VERSION_RELEASE * VERSION_RELEASE);

  (* Min. supported version by this header *)
  LIBAVFORMAT_MIN_VERSION_MAJOR   = 50;
  LIBAVFORMAT_MIN_VERSION_MINOR   = 5;
  LIBAVFORMAT_MIN_VERSION_RELEASE = 0;
  LIBAVFORMAT_MIN_VERSION = (LIBAVFORMAT_MIN_VERSION_MAJOR * VERSION_MAJOR) +
                            (LIBAVFORMAT_MIN_VERSION_MINOR * VERSION_MINOR) +
                            (LIBAVFORMAT_MIN_VERSION_RELEASE * VERSION_RELEASE);

(* Check if linked versions are supported *)
{$IF (LIBAVFORMAT_VERSION < LIBAVFORMAT_MIN_VERSION)}
  {$MESSAGE Error 'Linked version of libavformat is too old!'}
{$IFEND}

(* Check if linked versions are supported *)
{$IF (LIBAVFORMAT_VERSION > LIBAVFORMAT_MAX_VERSION)}
  {$MESSAGE Error 'Linked version of libavformat is not yet supported!'}
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52020000} // 52.20.0
(**
 * I return the LIBAVFORMAT_VERSION_INT constant.  You got
 * a fucking problem with that, douchebag?
 *)
function avformat_version(): cuint;
  cdecl; external av__format;
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52039002} // 52.39.2
(**
 * Returns the libavformat build-time configuration.
 *)
function avformat_configuration(): {const} PansiChar;
  cdecl; external av__format;

(**
 * Returns the libavformat license.
 *)
function avformat_license(): {const} PansiChar;
  cdecl; external av__format;
{$IFEND}

type
  PAVFile = Pointer;

(*
 * Public Metadata API.
 * The metadata API allows libavformat to export metadata tags to a client
 * application using a sequence of key/value pairs. Like all strings in FFmpeg,
 * metadata must be stored as UTF-8 encoded Unicode. Note that metadata
 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
 * Important concepts to keep in mind:
 * 1. Keys are unique; there can never be 2 tags with the same key. This is
 *    also meant semantically, i.e., a demuxer should not knowingly produce
 *    several keys that are literally different but semantically identical.
 *    E.g., key=Author5, key=Author6. In this example, all authors must be
 *    placed in the same tag.
 * 2. Metadata is flat, not hierarchical; there are no subtags. If you
 *    want to store, e.g., the email address of the child of producer Alice
 *    and actor Bob, that could have key=alice_and_bobs_childs_email_address.
 * 3. A tag whose value is localized for a particular language is appended
 *    with a dash character ('-') and the ISO 639-2/B 3-letter language code.
 *    For example: Author-ger=Michael, Author-eng=Mike
 *    The original/default language is in the unqualified "Author" tag.
 *    A demuxer should set a default if it sets any translated tag.
 *)
const
  AV_METADATA_MATCH_CASE    = 1;
  AV_METADATA_IGNORE_SUFFIX = 2;
{$IF LIBAVFORMAT_VERSION >= 52043000} // >= 52.43.0
  AV_METADATA_DONT_STRDUP_KEY = 4;
  AV_METADATA_DONT_STRDUP_VAL = 8;
{$IFEND}
{$IF LIBAVFORMAT_VERSION >= 52061000} // >= 52.61.0
  AV_METADATA_DONT_OVERWRITE  = 16;
{$IFEND}

type
  PAVMetadataTag = ^TAVMetadataTag;
  TAVMetadataTag = record
    key:   PAnsiChar;
    value: PAnsiChar;
  end;

  PAVMetadata = Pointer;

{$IF LIBAVFORMAT_VERSION > 52024001} // > 52.24.1
{$IF LIBAVFORMAT_VERSION_MAJOR = 52}
(**
 * Gets a metadata element with matching key.
 * @param prev Set to the previous matching element to find the next.
 *             If set to NULL the first matching element is returned.
 * @param flags Allows case as well as suffix-insensitive comparisons.
 * @return Found tag or NULL, changing key or value leads to undefined behavior.
 *)
function av_metadata_get(m: PAVMetadata; key: {const} PAnsiChar;
                         prev: {const} PAVMetadataTag ; flags: cint): PAVMetadataTag;
  cdecl; external av__format;

(**
 * Sets the given tag in m, overwriting an existing tag.
 * @param key tag key to add to m (will be av_strduped)
 * @param value tag value to add to m (will be av_strduped)
 * @return >= 0 on success otherwise an error code <0
 * @deprecated Use av_metadata_set2() instead.
 *)
function av_metadata_set(var pm: PAVMetadata; key: {const} PAnsiChar; value: {const} PAnsiChar): cint;
  cdecl; external av__format;
{$IF LIBAVFORMAT_VERSION >= 52061000} // >= 52.61.0
    deprecated;
{$IFEND}
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52043000} // >= 52.43.0
(**
 * Sets the given tag in m, overwriting an existing tag.
 * @param key tag key to add to m (will be av_strduped depending on flags)
 * @param value tag value to add to m (will be av_strduped depending on flags)
 * @return >= 0 on success otherwise an error code <0
 *)
function av_metadata_set2(var pm: PAVMetadata; key: {const} PAnsiChar; value: {const} PAnsiChar; flags: cint): cint;
  cdecl; external av__format;
{$IFEND}

(**
 * Frees all the memory allocated for an AVMetadata struct.
 *)
procedure av_metadata_free(var m: PAVMetadata);
  cdecl; external av__format;
{$IFEND}

(* packet functions *)

{$IF LIBAVFORMAT_VERSION < 52032000} // < 52.32.0
type
  PAVPacket = ^TAVPacket;
  TAVPacket = record
    (**
     * Presentation timestamp in time_base units; the time at which the
     * decompressed packet will be presented to the user.
     * Can be AV_NOPTS_VALUE if it is not stored in the file.
     * pts MUST be larger or equal to dts as presentation can not happen before
     * decompression, unless one wants to view hex dumps. Some formats misuse
     * the terms dts and pts/cts to mean something different. Such timestamps
     * must be converted to true pts/dts before they are stored in AVPacket.
     *)
    pts: cint64;
    (**
     * Decompression timestamp in time_base units; the time at which the
     * packet is decompressed.
     * Can be AV_NOPTS_VALUE if it is not stored in the file.
     *)
    dts: cint64;
    data: PByteArray;
    size: cint;
    stream_index: cint;
    flags: cint;
    (**
     * Duration of this packet in time_base units, 0 if unknown.
     * Equals next_pts - this_pts in presentation order.
     *)
    duration: cint;
    destruct: procedure (p: PAVPacket); cdecl;
    priv: pointer;
    pos: cint64;                            ///< byte position in stream, -1 if unknown

    {$IF LIBAVFORMAT_VERSION >= 52022000} // 52.22.0
    (**
     * Time difference in stream time base units from the pts of this
     * packet to the point at which the output from the decoder has converged
     * independent from the availability of previous frames. That is, the
     * frames are virtually identical no matter if decoding started from
     * the very first frame or from this keyframe.
     * Is AV_NOPTS_VALUE if unknown.
     * This field is not the display duration of the current packet.
     *
     * The purpose of this field is to allow seeking in streams that have no
     * keyframes in the conventional sense. It corresponds to the
     * recovery point SEI in H.264 and match_time_delta in NUT. It is also
     * essential for some types of subtitle streams to ensure that all
     * subtitles are correctly displayed after seeking.
     *)
    convergence_duration: cint64;
    {$IFEND}
  end;
  
const
  PKT_FLAG_KEY = $0001;

procedure av_destruct_packet_nofree(var pkt: TAVPacket);
  cdecl; external av__format;

(**
 * Default packet destructor.
 *)
procedure av_destruct_packet(var pkt: TAVPacket);
  cdecl; external av__format;

(**
 * Initialize optional fields of a packet with default values.
 *
 * @param pkt packet
 *)
procedure av_init_packet(var pkt: TAVPacket);
{$IF LIBAVFORMAT_VERSION >= 51012002} // 51.12.2
  cdecl; external av__format;
{$IFEND}

(**
 * Allocate the payload of a packet and initialize its fields with
 * default values.
 *
 * @param pkt packet
 * @param size wanted payload size
 * @return 0 if OK, AVERROR_xxx otherwise
 *)
function av_new_packet(var pkt: TAVPacket; size: cint): cint;
  cdecl; external av__format;
{$IFEND}

(**
 * Allocate and read the payload of a packet and initialize its fields with
 * default values.
 *
 * @param pkt packet
 * @param size desired payload size
 * @return >0 (read size) if OK, AVERROR_xxx otherwise
 *)
function av_get_packet(s: PByteIOContext; var pkt: TAVPacket; size: cint): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION < 52032000} // < 52.32.0
(**
 * @warning This is a hack - the packet memory allocation stuff is broken. The
 * packet is allocated if it was not really allocated.
 *)
function av_dup_packet(pkt: PAVPacket): cint;
  cdecl; external av__format;

(**
 * Free a packet.
 *
 * @param pkt packet to free
 *)
procedure av_free_packet(pkt: PAVPacket); {$IFDEF HasInline}inline;{$ENDIF}
{$IFEND}

(*************************************************)
(* fractional numbers for exact pts handling *)

type
 (**
  * The exact value of the fractional number is: 'val + num / den'.
  * num is assumed to be 0 <= num < den.
  *)
  PAVFrac = ^TAVFrac;
  TAVFrac = record
    val, num, den: cint64;
  end;

(*************************************************)
(* input/output formats *)

type
  (** This structure contains the data a format has to probe a file. *)
  TAVProbeData = record
    filename: PAnsiChar;
    buf: PByteArray;  (**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. *)
    buf_size: cint;   (**< Size of buf except extra allocated bytes *)
  end;

const
  AVPROBE_SCORE_MAX   = 100;   ///< Maximum score, half of that is used for file-extension-based detection
  AVPROBE_PADDING_SIZE = 32;   ///< extra allocated bytes at the end of the probe buffer

  //! Demuxer will use url_fopen, no opened file should be provided by the caller.
  AVFMT_NOFILE        = $0001;
  AVFMT_NEEDNUMBER    = $0002; (**< Needs '%d' in filename. *)
  AVFMT_SHOW_IDS      = $0008; (**< Show format stream IDs numbers. *)
  AVFMT_RAWPICTURE    = $0020; (**< Format wants AVPicture structure for
                                      raw picture data. *)
  AVFMT_GLOBALHEADER  = $0040; (**< Format wants global header. *)
  AVFMT_NOTIMESTAMPS  = $0080; (**< Format does not need / have any timestamps. *)
  AVFMT_GENERIC_INDEX = $0100; (**< Use generic index building code. *)
  AVFMT_TS_DISCONT    = $0200; (**< Format allows timestamp discontinuities. *)
  {$IF LIBAVFORMAT_VERSION >= 52029002} // 52.29.2
  AVFMT_VARIABLE_FPS  = $0400; (**< Format allows variable fps. *)
  {$IFEND}
  {$IF LIBAVFORMAT_VERSION >= 52052000} // 52.52.0
  AVFMT_NODIMENSIONS  = $0800; (**< Format does not need width/height *)
  {$IFEND}

  // used by AVIndexEntry
  AVINDEX_KEYFRAME = $0001;

  AVFMTCTX_NOHEADER = $0001; (**< signal that no header is present
                                         (streams are added dynamically) *)
{$IF LIBAVFORMAT_VERSION_MAJOR < 53}
  MAX_STREAMS = 20;
{$ELSE}
  MAX_STREAMS = 100;
{$IFEND}

  AVFMT_NOOUTPUTLOOP = -1;
  AVFMT_INFINITEOUTPUTLOOP = 0;
  AVFMT_FLAG_GENPTS = $0001;   ///< Generate missing pts even if it requires parsing future frames.
  AVFMT_FLAG_IGNIDX = $0002;   ///< Ignore index.
  AVFMT_FLAG_NONBLOCK = $0004; ///< Do not block when reading packets from input.
{$IF LIBAVFORMAT_VERSION >= 52048000}  // >= 52.48.0
  AVFMT_FLAG_IGNDTS   = $0008; ///< Ignore DTS on frames that contain both DTS & PTS
{$IFEND}
{$IF LIBAVFORMAT_VERSION >= 52060000}  // >= 52.60.0
  AVFMT_FLAG_NOFILLIN = $0010; ///< Do not infer any values from other values, just return what is stored in the container
  AVFMT_FLAG_NOPARSE  = $0020; ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing -> no frames. Also seeking to frames can not work if parsing to find frame boundaries has been disabled
{$IFEND}
{$IF LIBAVFORMAT_VERSION >= 52063000}  // >= 52.63.0
  AVFMT_FLAG_RTP_HINT = $0040; ///< Add RTP hinting to the output file
{$IFEND}

  // used by AVStream
  MAX_REORDER_DELAY = 16;

  // used by TAVProgram
  AV_PROGRAM_RUNNING = 1;


  AV_DISPOSITION_DEFAULT   = $0001;
  AV_DISPOSITION_DUB       = $0002;
  AV_DISPOSITION_ORIGINAL  = $0004;
  AV_DISPOSITION_COMMENT   = $0008;
  AV_DISPOSITION_LYRICS    = $0010;
  AV_DISPOSITION_KARAOKE   = $0020;

  // used by TAVFormatContext.debug
  FF_FDEBUG_TS = 0001;

  {$IF LIBAVFORMAT_VERSION >= 52034000}  // >= 52.34.0
    {$IF LIBAVFORMAT_VERSION < 52039000} // <  52.39.0
  MAX_PROBE_PACKETS = 100;
    {$ELSE}
  MAX_PROBE_PACKETS = 2500;
    {$IFEND}
  {$IFEND}

  {$IF LIBAVFORMAT_VERSION >= 52035000}  // >= 52.35.0
    {$IF LIBAVFORMAT_VERSION < 52039000} // <  52.39.0
  RAW_PACKET_BUFFER_SIZE = 32000;
    {$ELSE}
  RAW_PACKET_BUFFER_SIZE = 2500000;
    {$IFEND}
  {$IFEND}

type
  PPAVCodecTag = ^PAVCodecTag;
  PAVCodecTag = Pointer;

  PPAVFormatContext = ^PAVFormatContext;
  PAVFormatContext = ^TAVFormatContext;

  PAVFormatParameters = ^TAVFormatParameters;

  PAVOutputFormat = ^TAVOutputFormat;
  PAVProbeData = ^TAVProbeData;

  PAVInputFormat = ^TAVInputFormat;
  PAVIndexEntry = ^TAVIndexEntry;

  PAVStream = ^TAVStream;
  PAVPacketList = ^TAVPacketList;

  PPAVProgram = ^PAVProgram;
  PAVProgram = ^TAVProgram;

  {$IF LIBAVFORMAT_VERSION < 51006000} // 51.6.0
  PAVImageFormat = ^TAVImageFormat;
  PAVImageInfo = ^TAVImageInfo;
  {$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52030001} // >= 52.30.1
(**
 * Convert all the metadata sets from ctx according to the source and
 * destination conversion tables.
 * @param d_conv destination tags format conversion table
 * @param s_conv source tags format conversion table
 *)
  PAVMetadataConv = ^TAVMetadataConv;
  TAVMetadataConv = record
    ctx:            PAVFormatContext;
    d_conv: {const} PAVMetadataConv;
    s_conv: {const} PAVMetadataConv;
  end;
{$IFEND}

  PAVChapter = ^TAVChapter;
  TAVChapter = record
    id: cint;                 ///< unique ID to identify the chapter
    time_base: TAVRational;   ///< time base in which the start/end timestamps are specified
    start, end_: cint64;      ///< chapter start/end time in time_base units
    {$IF LIBAVFORMAT_VERSION < 53000000}  // 53.00.0
    title: PAnsiChar;         ///< chapter title
    {$IFEND}
    {$IF LIBAVFORMAT_VERSION >= 52024001} // 52.24.1
    metadata: PAVMetadata;
    {$IFEND}
  end;
  TAVChapterArray = array[0..(MaxInt div SizeOf(TAVChapter))-1] of TAVChapter;
  PAVChapterArray = ^TAVChapterArray;

  TAVFormatParameters = record
    time_base: TAVRational;
    sample_rate: cint;
    channels: cint;
    width: cint;
    height: cint;
    pix_fmt: TAVPixelFormat;
    {$IF LIBAVFORMAT_VERSION < 51006000} // 51.6.0
    image_format: PAVImageFormat;
    {$IFEND}
    channel: cint; (**< Used to select DV channel. *)
    {$IF LIBAVFORMAT_VERSION_MAJOR < 52}
    device: PAnsiChar; (* video, audio or DV device, if LIBAVFORMAT_VERSION_INT < (52<<16) *)
    {$IFEND}
    standard: PAnsiChar; (**< TV standard, NTSC, PAL, SECAM *)
    { Delphi does not support bit fields -> use bf_flags instead
    unsigned int mpeg2ts_raw:1;  (**< Force raw MPEG-2 transport stream output, if possible. *)
    unsigned int mpeg2ts_compute_pcr:1; (**< Compute exact PCR for each transport
                                  stream packet (only meaningful if
                                  mpeg2ts_raw is TRUE). *)
    unsigned int initial_pause:1;       (**< Do not begin to play the stream
                                        immediately (RTSP only). *)
    unsigned int prealloced_context:1;
    }
    bf_flags: byte; // 0:mpeg2ts_raw/1:mpeg2ts_compute_pcr/2:initial_pause/3:prealloced_context
    {$IF LIBAVFORMAT_VERSION_MAJOR < 53}
    video_codec_id: TCodecID;
    audio_codec_id: TCodecID;
    {$IFEND}
  end;

  TAVOutputFormat = record
    name: PAnsiChar;
    (**
     * Descriptive name for the format, meant to be more human-readable
     * than name. You should use the NULL_IF_CONFIG_SMALL() macro
     * to define it.
     *)
    long_name: PAnsiChar;
    mime_type: PAnsiChar;
    extensions: PAnsiChar; (**< comma-separated filename extensions *)
    (** size of private data so that it can be allocated in the wrapper *)
    priv_data_size: cint;
    (* output support *)
    audio_codec: TCodecID; (**< default audio codec *)
    video_codec: TCodecID; (**< default video codec *)
    write_header: function (c: PAVFormatContext): cint; cdecl;
    write_packet: function (c: PAVFormatContext; pkt: PAVPacket): cint; cdecl;
    write_trailer: function (c: PAVFormatContext): cint; cdecl;
    (** can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER *)
    flags: cint;
    (** Currently only used to set pixel format if not YUV420P. *)
    set_parameters: function (c: PAVFormatContext; f: PAVFormatParameters): cint; cdecl;
    interleave_packet: function (s: PAVFormatContext; out_: PAVPacket;
                                 in_: PAVPacket; flush: cint): cint; cdecl;

    {$IF LIBAVFORMAT_VERSION >= 51008000} // 51.8.0
    (**
     * List of supported codec_id-codec_tag pairs, ordered by "better
     * choice first". The arrays are all terminated by CODEC_ID_NONE.
     *)
    codec_tag: {const} PPAVCodecTag;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 51012002} // 51.12.2
    subtitle_codec: TCodecID; (**< default subtitle codec *)
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52030001} // 52.30.1
    {const} metadata_conv: PAVMetadataConv;
    {$IFEND}

    (* private fields *)
    next: PAVOutputFormat;
  end;

  TAVInputFormat = record
    name: PAnsiChar;
    (**
     * Descriptive name for the format, meant to be more human-readable
     * than name. You should use the NULL_IF_CONFIG_SMALL() macro
     * to define it.
     *)
    long_name: PAnsiChar;
    (** Size of private data so that it can be allocated in the wrapper. *)
    priv_data_size: cint;
    (**
     * Tell if a given file has a chance of being parsed as this format.
     * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
     * big so you do not have to check for that unless you need more.
     *)
    read_probe: function (p: PAVProbeData): cint; cdecl;
    (** Read the format header and initialize the AVFormatContext
       structure. Return 0 if OK. 'ap' if non-NULL contains
       additional parameters. Only used in raw format right
       now. 'av_new_stream' should be called to create new streams.  *)
    read_header: function (c: PAVFormatContext; ap: PAVFormatParameters): cint; cdecl;
    (** Read one packet and put it in 'pkt'. pts and flags are also
       set. 'av_new_stream' can be called only if the flag
       AVFMTCTX_NOHEADER is used.
       @return 0 on success, < 0 on error.
               When returning an error, pkt must not have been allocated
               or must be freed before returning *)
    read_packet: function (c: PAVFormatContext; var pkt: TAVPacket): cint; cdecl;
    (** Close the stream. The AVFormatContext and AVStreams are not
       freed by this function *)
    read_close: function (c: PAVFormatContext): cint; cdecl;

{$IF LIBAVFORMAT_VERSION_MAJOR < 53}
    (**
     * Seek to a given timestamp relative to the frames in
     * stream component stream_index.
     * @param stream_index Must not be -1.
     * @param flags Selects which direction should be preferred if no exact
     *              match is available.
     * @return >= 0 on success (but not necessarily the new offset)
     *)
    read_seek: function (c: PAVFormatContext; stream_index: cint;
                  timestamp: cint64; flags: cint): cint; cdecl;
{$IFEND}

    (**
     * Gets the next timestamp in stream[stream_index].time_base units.
     * @return the timestamp or AV_NOPTS_VALUE if an error occurred
     *)
    read_timestamp: function (s: PAVFormatContext; stream_index: cint;
                              pos: pint64; pos_limit: cint64): cint64; cdecl;
    (** Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER. *)
    flags: cint;
    (** If extensions are defined, then no probe is done. You should
       usually not use extension format guessing because it is not
       reliable enough *)
    extensions: PAnsiChar;
    (** General purpose read-only value that the format can use. *)
    value: cint;

    (** Starts/resumes playing - only meaningful if using a network-based format
       (RTSP). *)
    read_play: function (c: PAVFormatContext): cint; cdecl;

    (** Pauses playing - only meaningful if using a network-based format
      (RTSP). *)  
    read_pause: function (c: PAVFormatContext): cint; cdecl;

    {$IF LIBAVFORMAT_VERSION >= 51008000} // 51.8.0
    codec_tag: {const} PPAVCodecTag;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52030000} // 52.30.0
    (**
     * Seeks to timestamp ts.
     * Seeking will be done so that the point from which all active streams
     * can be presented successfully will be closest to ts and within min/max_ts.
     * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
     *)
    read_seek2: function (s:            PAVFormatContext;
                          stream_index: cint;
			  min_ts:       cint64;
			  ts:           cint64; 
			  max_ts:       cint64;
			  flags:        cint): cint; cdecl;
    {$IFEND}
    
    {$IF LIBAVFORMAT_VERSION >= 52030001} // 52.30.1
    {const} metadata_conv: PAVMetadataConv;
    {$IFEND}

    (* private fields *)
    next: PAVInputFormat;
  end;

  TAVStreamParseType = (
    AVSTREAM_PARSE_NONE,
    AVSTREAM_PARSE_FULL,       (**< full parsing and repack *)
    AVSTREAM_PARSE_HEADERS,    (**< Only parse headers, do not repack. *)
    AVSTREAM_PARSE_TIMESTAMPS  (**< full parsing and interpolation of timestamps for frames not starting on a packet boundary *)
  );

  TAVIndexEntry = record
    pos: cint64;
    timestamp: cint64;
    { Delphi doesn't support bitfields -> use flags_size instead
    int flags:2;
    int size:30; //Yeah, trying to keep the size of this small to reduce memory requirements (it is 24 vs. 32 bytes due to possible 8-byte alignment).
    }
    flags_size: cint; // 0..1: flags, 2..31: size
    min_distance: cint;         (**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. *)
  end;

 (**
  * Stream structure.
  * New fields can be added to the end with minor version bumps.
  * Removal, reordering and changes to existing fields require a major
  * version bump.
  * sizeof(AVStream) must not be used outside libav*.
  *)
  TAVStream = record
    index: cint;    (**< stream index in AVFormatContext *)
    id: cint;       (**< format-specific stream ID *)
    codec: PAVCodecContext; (**< codec context *)
    (**
     * Real base framerate of the stream.
     * This is the lowest framerate with which all timestamps can be
     * represented accurately (it is the least common multiple of all
     * framerates in the stream). Note, this value is just a guess!
     * For example, if the time base is 1/90000 and all frames have either
     * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
     *)
    r_frame_rate: TAVRational;
    priv_data: pointer;

    (* internal data used in av_find_stream_info() *)
    first_dts: cint64;
    {$IF LIBAVFORMAT_VERSION_MAJOR < 52}
    codec_info_nb_frames: cint;
    {$IFEND}

    (** encoding: pts generation when outputting stream *)
    pts: TAVFrac;
    (**
     * This is the fundamental unit of time (in seconds) in terms
     * of which frame timestamps are represented. For fixed-fps content,
     * time base should be 1/framerate and timestamp increments should be 1.
     *)
    time_base: TAVRational;
    pts_wrap_bits: cint; (* number of bits in pts (used for wrapping control) *)
    (* ffmpeg.c private use *)
    stream_copy: cint; (**< If set, just copy stream. *)
    discard: TAVDiscard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
    //FIXME move stuff to a flags field?
    (** Quality, as it has been removed from AVCodecContext and put in AVVideoFrame.
     * MN:dunno if thats the right place, for it *)
    quality: cfloat;
    (**
     * Decoding: pts of the first frame of the stream, in stream time base.
     * Only set this if you are absolutely 100% sure that the value you set
     * it to really is the pts of the first frame.
     * This may be undefined (AV_NOPTS_VALUE).
     * @note The ASF header does NOT contain a correct start_time the ASF
     * demuxer must NOT set this.
     *)
    start_time: cint64;
    (**
     * Decoding: duration of the stream, in stream time base.
     * If a source file does not specify a duration, but does specify
     * a bitrate, this value will be estimated from bitrate and file size.
     *)
    duration: cint64;

    {$IF LIBAVFORMAT_VERSION_MAJOR < 53}
    language: array [0..3] of PAnsiChar; (* ISO 639-2/B 3-letter language code (empty string if undefined) *)
    {$IFEND}

    (* av_read_frame() support *)
    need_parsing: TAVStreamParseType;
    parser: PAVCodecParserContext;

    cur_dts: cint64;
    last_IP_duration: cint;
    last_IP_pts: cint64;
    (* av_seek_frame() support *)
    index_entries: PAVIndexEntry; (**< Only used if the format does not
                                       support seeking natively. *)
    nb_index_entries: cint;
    index_entries_allocated_size: cuint;

    nb_frames: cint64;                 ///< number of frames in this stream if known or 0
    
    {$IF (LIBAVFORMAT_VERSION >= 50006000) and (LIBAVFORMAT_VERSION_MAJOR < 53)} // 50.6.0 - 53.0.0
    unused: array [0..4] of cint64;
    {$IFEND}

    {$IF (LIBAVFORMAT_VERSION >= 52006000) and (LIBAVFORMAT_VERSION_MAJOR < 53)} // 52.6.0 - 53.0.0
    filename: PAnsiChar; (**< source filename of the stream *)
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52008000} // 52.8.0
    disposition: cint; (**< AV_DISPOSITION_* bitfield *)
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52019000} // 52.19.0
    probe_data: TAVProbeData;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52021000} // 52.21.0
    pts_buffer: array [0..MAX_REORDER_DELAY] of cint64;

    (**
     * sample aspect ratio (0 if unknown)
     * - encoding: Set by user.
     * - decoding: Set by libavformat.
     *)
    sample_aspect_ratio: TAVRational;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52024001} // 52.24.1
    metadata: PAVMetadata;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION > 52024001} // > 52.24.1
    {* av_read_frame() support *}
    cur_ptr: {const} PCuint8;
    cur_len: cint;
    cur_pkt: TAVPacket;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52030000} // > 52.30.0
    // Timestamp generation support:
    (**
     * Timestamp corresponding to the last dts sync point.
     *
     * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
     * a DTS is received from the underlying container. Otherwise set to
     * AV_NOPTS_VALUE by default.
     *)
    reference_dts: cint64;
    {$IFEND}
    {$IF LIBAVFORMAT_VERSION >= 52034000} // >= 52.34.0
    (**
     * Number of packets to buffer for codec probing
     * NOT PART OF PUBLIC API
     *)
    probe_packets: cint;
    {$IFEND}
    {$IF LIBAVFORMAT_VERSION >= 52038000} // >= 52.38.0
    (**
     * last packet in packet_buffer for this stream when muxing.
     * used internally, NOT PART OF PUBLIC API, dont read or write from outside of libav*
     *)
    last_in_packet_buffer: PAVPacketList;
    {$IFEND}
    {$IF LIBAVFORMAT_VERSION >= 52041000} // >= 52.41.0
    (**
     * Average framerate
     *)
    avg_frame_rate: TAVRational;
    {$IFEND}
    {$IF LIBAVFORMAT_VERSION >= 52054000} // >= 52.54.0
    (**
     * Number of frames that have been demuxed during av_find_stream_info()
     *)
    codec_info_nb_frames: cint;
    {$IFEND}
  end;

 (**
  * Format I/O context.
  * New fields can be added to the end with minor version bumps.
  * Removal, reordering and changes to existing fields require a major
  * version bump.
  * sizeof(AVFormatContext) must not be used outside libav*.
  *)
  TAVFormatContext = record
    av_class: PAVClass; (**< Set by avformat_alloc_context. *)
    (* Can only be iformat or oformat, not both at the same time. *)
    iformat: PAVInputFormat;
    oformat: PAVOutputFormat;
    priv_data: pointer;

    {$IF LIBAVFORMAT_VERSION_MAJOR >= 52}
    pb: PByteIOContext;
    {$ELSE}
    pb: TByteIOContext;
    {$IFEND}

    nb_streams: cuint;
    streams: array [0..MAX_STREAMS - 1] of PAVStream;
    filename: array [0..1023] of AnsiChar; (* input or output filename *)
    (* stream info *)
    timestamp: cint64;
    {$IF LIBAVFORMAT_VERSION < 53000000} // 53.00.0
    title: array [0..511] of AnsiChar;
    author: array [0..511] of AnsiChar;
    copyright: array [0..511] of AnsiChar;
    comment: array [0..511] of AnsiChar;
    album: array [0..511] of AnsiChar;
    year: cint;  (**< ID3 year, 0 if none *)
    track: cint; (**< track number, 0 if none *)
    genre: array [0..31] of AnsiChar; (**< ID3 genre *)
    {$IFEND}

    ctx_flags: cint; (**< Format-specific flags, see AVFMTCTX_xx *)
    (* private data for pts handling (do not modify directly). *)
    (** This buffer is only needed when packets were already buffered but
       not decoded, for example to get the codec parameters in MPEG
       streams. *)
    packet_buffer: PAVPacketList;

    (** Decoding: position of the first frame of the component, in
       AV_TIME_BASE fractional seconds. NEVER set this value directly:
       It is deduced from the AVStream values. *)
    start_time: cint64;
    (** Decoding: duration of the stream, in AV_TIME_BASE fractional
        seconds. Only set this value if you know none of the individual stream
        durations and also dont set any of them. This is deduced from the
        AVStream values if not set.  *)
    duration: cint64;
    (** decoding: total file size, 0 if unknown *)
    file_size: cint64;
    (** Decoding: total stream bitrate in bit/s, 0 if not
       available. Never set it directly if the file_size and the
       duration are known as ffmpeg can compute it automatically. *)
    bit_rate: cint;

    (* av_read_frame() support *)
    cur_st: PAVStream;
    {$IF LIBAVFORMAT_VERSION_MAJOR < 53}
    cur_ptr_deprecated: pbyte;
    cur_len_deprecated: cint;
    cur_pkt_deprecated: TAVPacket;
    {$IFEND}

    (* av_seek_frame() support *)
    data_offset: cint64; (* offset of the first packet *)
    index_built: cint;

    mux_rate: cint;
    {$IF LIBAVFORMAT_VERSION < 52034001} // < 52.34.1
    packet_size: cint;
    {$ELSE}
    packet_size: cuint;
    {$IFEND}
    preload: cint;
    max_delay: cint;

    (* number of times to loop output in formats that support it *)
    loop_output: cint;

    flags: cint;
    loop_input: cint;

    {$IF LIBAVFORMAT_VERSION >= 50006000} // 50.6.0
    (** decoding: size of data to probe; encoding: unused. *)
    probesize: cuint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 51009000} // 51.9.0
    (**
     * Maximum time (in AV_TIME_BASE units) during which the input should
     * be analyzed in av_find_stream_info().
     *)
    max_analyze_duration: cint;

    key: pbyte;
    keylen : cint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 51014000} // 51.14.0
    nb_programs: cuint;
    programs: PPAVProgram;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52003000} // 52.3.0
    (**
     * Forced video codec_id.
     * Demuxing: Set by user.
     *)
    video_codec_id: TCodecID;
    (**
     * Forced audio codec_id.
     * Demuxing: Set by user.
     *)
    audio_codec_id: TCodecID;
    (**
     * Forced subtitle codec_id.
     * Demuxing: Set by user.
     *)
    subtitle_codec_id: TCodecID;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52004000} // 52.4.0
    (**
     * Maximum amount of memory in bytes to use for the index of each stream.
     * If the index exceeds this size, entries will be discarded as
     * needed to maintain a smaller size. This can lead to slower or less
     * accurate seeking (depends on demuxer).
     * Demuxers for which a full in-memory index is mandatory will ignore
     * this.
     * muxing  : unused
     * demuxing: set by user
     *)
    max_index_size: cuint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52009000} // 52.9.0
    (**
     * Maximum amount of memory in bytes to use for buffering frames
     * obtained from realtime capture devices.
     *)
    max_picture_buffer: cuint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52014000} // 52.14.0
    nb_chapters: cuint;
    chapters: PAVChapterArray;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52016000} // 52.16.0
    (**
     * Flags to enable debugging.
     *)
    debug: cint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52019000} // 52.19.0
    (**
     * Raw packets from the demuxer, prior to parsing and decoding.
     * This buffer is used for buffering packets until the codec can
     * be identified, as parsing cannot be done without knowing the
     * codec.
     *)
    raw_packet_buffer: PAVPacketList;
    raw_packet_buffer_end: PAVPacketList;

    packet_buffer_end: PAVPacketList;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52024001} // 52.24.1
    metadata: PAVMetadata;
    {$IFEND}
    
    {$IF LIBAVFORMAT_VERSION >= 52035000} // 52.35.0
    (**
     * Remaining size available for raw_packet_buffer, in bytes.
     * NOT PART OF PUBLIC API
     *)
    raw_packet_buffer_remaining_size: cint;
    {$IFEND}

    {$IF LIBAVFORMAT_VERSION >= 52056000} // 52.56.0
    (**
     * Start time of the stream in real world time, in microseconds
     * since the unix epoch (00:00 1st January 1970). That is, pts=0
     * in the stream was captured at this real world time.
     * - encoding: Set by user.
     * - decoding: Unused.
     *)
    start_time_realtime: cint64;
    {$IFEND}

  end;

  (**
   * New fields can be added to the end with minor version bumps.
   * Removal, reordering and changes to existing fields require a major
   * version bump.
   * sizeof(AVProgram) must not be used outside libav*.
   *)
  TAVProgram = record
      id                : cint;
      {$IF LIBAVFORMAT_VERSION < 53000000} // 53.00.0
      provider_name     : PAnsiChar;  ///< network name for DVB streams
      name              : PAnsiChar;  ///< service name for DVB streams
      {$IFEND}
      flags             : cint;
      discard           : TAVDiscard; ///< selects which program to discard and which to feed to the caller
      {$IF LIBAVFORMAT_VERSION >= 51016000} // 51.16.0
      stream_index      : PCardinal;
      nb_stream_indexes : PCardinal;
      {$IFEND}
      {$IF LIBAVFORMAT_VERSION >= 52024001} // 52.24.1
      metadata: PAVMetadata;
      {$IFEND}
  end;

  TAVPacketList = record
    pkt: TAVPacket;
    next: PAVPacketList;
  end;

{$IF LIBAVFORMAT_VERSION < 51006000} // 51.6.0
  (* still image support *)
  PAVInputImageContext = pointer; {deprecated}

  (* still image support *)
  TAVImageInfo = record
    pix_fmt: TAVPixelFormat; (* requested pixel format *)
    width: cint; (* requested width *)
    height: cint; (* requested height *)
    interleaved: cint; (* image is interleaved (e.g. interleaved GIF) *)
    pict: TAVPicture; (* returned allocated image *)
  end; {deprecated}

  TAVImageFormat = record
    name: PAnsiChar;
    extensions: PAnsiChar;
    (* tell if a given file has a chance of being parsing by this format *)
    img_probe: function (d: PAVProbeData): cint; cdecl;
    (* read a whole image. 'alloc_cb' is called when the image size is
       known so that the caller can allocate the image. If 'allo_cb'
       returns non zero, then the parsing is aborted. Return '0' if
       OK. *)
    img_read: function (b: PByteIOContext; alloc_cb: pointer; ptr: pointer): cint; cdecl;
    (* write the image *)
    supported_pixel_formats: cint; (* mask of supported formats for output *)
    img_write: function (b: PByteIOContext; i: PAVImageInfo): cint; cdecl;
    flags: cint;
    next: PAVImageFormat;
  end; {deprecated}

procedure av_register_image_format(img_fmt: PAVImageFormat);
    cdecl; external av__format; deprecated;

function av_probe_image_format(pd: PAVProbeData): PAVImageFormat;
    cdecl; external av__format; deprecated;

function guess_image_format(filename: PAnsiChar): PAVImageFormat;
    cdecl; external av__format; deprecated;

function av_read_image(pb: PByteIOContext; filename: PAnsiChar;
                  fmt: PAVImageFormat;
                  alloc_cb: pointer; opaque: pointer): cint;
    cdecl; external av__format; deprecated;

function av_write_image(pb: PByteIOContext; fmt: PAVImageFormat; img: PAVImageInfo): cint;
    cdecl; external av__format; deprecated;
{$IFEND}

{$IF LIBAVFORMAT_VERSION_MAJOR < 53}
{
var
  first_iformat: PAVInputFormat; external av__format;
  first_oformat: PAVOutputFormat; external av__format;
}
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52003000} // 52.3.0
(**
 * If f is NULL, returns the first registered input format,
 * if f is non-NULL, returns the next registered input format after f
 * or NULL if f is the last one.
 *)
function av_iformat_next(f: PAVInputFormat): PAVInputFormat;
    cdecl; external av__format;
(**
 * If f is NULL, returns the first registered output format,
 * if f is non-NULL, returns the next registered input format after f
 * or NULL if f is the last one.
 *)
function av_oformat_next(f: PAVOutputFormat): PAVOutputFormat;
    cdecl; external av__format;
{$IFEND}

function av_guess_image2_codec(filename: {const} PAnsiChar): TCodecID;
    cdecl; external av__format;

(* XXX: Use automatic init with either ELF sections or C file parser *)
(* modules. *)

(* utils.c *)
procedure av_register_input_format(format: PAVInputFormat);
  cdecl; external av__format;

procedure av_register_output_format(format: PAVOutputFormat);
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION_MAJOR < 53} // < 53
function guess_stream_format(short_name: PAnsiChar;
                             filename: PAnsiChar;
                             mime_type: PAnsiChar): PAVOutputFormat;
  cdecl; external av__format; deprecated;
{$IFEND}

(**
 * Returns the output format in the list of registered output formats
 * which best matches the provided parameters, or returns NULL if
 * there is no match.
 *
 * @param short_name if non-NULL checks if short_name matches with the
 * names of the registered formats
 * @param filename if non-NULL checks if filename terminates with the
 * extensions of the registered formats
 * @param mime_type if non-NULL checks if mime_type matches with the
 * MIME type of the registered formats
 *)
(**
 * @deprecated Use av_guess_format() instead.
 *)
function guess_format(short_name: PAnsiChar;
                      filename: PAnsiChar;
                      mime_type: PAnsiChar): PAVOutputFormat;
  cdecl; external av__format;
{$IF LIBAVFORMAT_VERSION >= 52045000} // >= 52.45.0
                              deprecated;
function av_guess_format(short_name: PAnsiChar;
                         filename: PAnsiChar;
                         mime_type: PAnsiChar): PAVOutputFormat;
  cdecl; external av__format;
{$IFEND}

(**
 * Guesses the codec ID based upon muxer and filename.
 *)
function av_guess_codec(fmt: PAVOutputFormat; short_name: PAnsiChar;
                        filename: PAnsiChar; mime_type: PAnsiChar;
                        type_: TCodecType): TCodecID;
  cdecl; external av__format;

(**
 * Sends a nice hexadecimal dump of a buffer to the specified file stream.
 *
 * @param f The file stream pointer where the dump should be sent to.
 * @param buf buffer
 * @param size buffer size
 *
 * @see av_hex_dump_log, av_pkt_dump, av_pkt_dump_log
 *)
procedure av_hex_dump(f: PAVFile; buf: PByteArray; size: cint);
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 51011000} // 51.11.0
(**
 * Sends a nice hexadecimal dump of a buffer to the log.
 *
 * @param avcl A pointer to an arbitrary struct of which the first field is a
 * pointer to an AVClass struct.
 * @param level The importance level of the message, lower values signifying
 * higher importance.
 * @param buf buffer
 * @param size buffer size
 *
 * @see av_hex_dump, av_pkt_dump, av_pkt_dump_log
 *)
procedure av_hex_dump_log(avcl: Pointer; level: cint; buf: PByteArray; size: cint);
  cdecl; external av__format;
{$IFEND}

(**
 * Sends a nice dump of a packet to the specified file stream.
 *
 * @param f The file stream pointer where the dump should be sent to.
 * @param pkt packet to dump
 * @param dump_payload True if the payload must be displayed, too.
 *)
procedure av_pkt_dump(f: PAVFile; pkt: PAVPacket; dump_payload: cint);
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 51011000} // 51.11.0
(**
 * Sends a nice dump of a packet to the log.
 *
 * @param avcl A pointer to an arbitrary struct of which the first field is a
 * pointer to an AVClass struct.
 * @param level The importance level of the message, lower values signifying
 * higher importance.
 * @param pkt packet to dump
 * @param dump_payload True if the payload must be displayed, too.
 *)
procedure av_pkt_dump_log(avcl: Pointer; level: cint; pkt: PAVPacket; dump_payload: cint);
  cdecl; external av__format;
{$IFEND}

(**
 * Initializes libavformat and registers all the muxers, demuxers and
 * protocols. If you do not call this function, then you can select
 * exactly which formats you want to support.
 *
 * @see av_register_input_format()
 * @see av_register_output_format()
 * @see av_register_protocol()
 *)
procedure av_register_all();
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 51008000} // 51.8.0
(**
 * Gets the CodecID for the given codec tag tag.
 * If no codec id is found returns CODEC_ID_NONE.
 *
 * @param tags list of supported codec_id-codec_tag pairs, as stored
 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
 *)
function av_codec_get_id(var tags: PAVCodecTag; tag: cuint): TCodecID;
  cdecl; external av__format;

(**
 * Gets the codec tag for the given codec id id.
 * If no codec tag is found returns 0.
 *
 * @param tags list of supported codec_id-codec_tag pairs, as stored
 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
 *)
function av_codec_get_tag(var tags: PAVCodecTag; id: TCodecID): cuint;
  cdecl; external av__format;
{$IFEND}

(* media file input *)

(**
 * Finds AVInputFormat based on the short name of the input format.
 *)
function av_find_input_format(short_name: PAnsiChar): PAVInputFormat;
  cdecl; external av__format;

(**
 * Guesses file format.
 *
 * @param is_opened Whether the file is already opened; determines whether
 *                  demuxers with or without AVFMT_NOFILE are probed.
 *)
function av_probe_input_format(pd: PAVProbeData; is_opened: cint): PAVInputFormat;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52062000} // 52.62.0
(**
 * Guesses the file format.
 *
 * @param is_opened Whether the file is already opened; determines whether
 *                  demuxers with or without AVFMT_NOFILE are probed.
 * @param score_max A probe score larger that this is required to accept a
 *                  detection, the variable is set to the actual detection
 *                  score afterwards.
 *                  If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
 *                  to retry with a larger probe buffer.
 *)
function av_probe_input_format2(pd: PAVProbeData; is_opened: cint; score_max: PCint): PAVInputFormat;
  cdecl; external av__format;
{$IFEND}

(**
 * Allocates all the structures needed to read an input stream.
 *        This does not open the needed codecs for decoding the stream[s].
 *)
function av_open_input_stream(var ic_ptr: PAVFormatContext;
                       pb: PByteIOContext; filename: PAnsiChar;
                       fmt: PAVInputFormat; ap: PAVFormatParameters): cint;
  cdecl; external av__format;

(**
 * Opens a media file as input. The codecs are not opened. Only the file
 * header (if present) is read.
 *
 * @param ic_ptr The opened media file handle is put here.
 * @param filename filename to open
 * @param fmt If non-NULL, force the file format to use.
 * @param buf_size optional buffer size (zero if default is OK)
 * @param ap Additional parameters needed when opening the file
 *           (NULL if default).
 * @return 0 if OK, AVERROR_xxx otherwise
 *)
function av_open_input_file(var ic_ptr: PAVFormatContext; filename: PAnsiChar;
                     fmt: PAVInputFormat; buf_size: cint;
                     ap: PAVFormatParameters): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52026000} // 52.26.0
(**
 * Allocates an AVFormatContext.
 * Can be freed with av_free() but do not forget to free everything you
 * explicitly allocated as well!
 *)
function avformat_alloc_context(): PAVFormatContext;
  cdecl; external av__format;
{$ELSE}
  {$IF LIBAVFORMAT_VERSION_MAJOR < 53}
(**
 * @deprecated Use avformat_alloc_context() instead.
 *)
function av_alloc_format_context(): PAVFormatContext;
  cdecl; external av__format;
  {$IFEND}
{$IFEND}

(**
 * Reads packets of a media file to get stream information. This
 * is useful for file formats with no headers such as MPEG. This
 * function also computes the real framerate in case of MPEG-2 repeat
 * frame mode.
 * The logical file position is not changed by this function;
 * examined packets may be buffered for later processing.
 *
 * @param ic media file handle
 * @return >=0 if OK, AVERROR_xxx on error
 * @todo Let the user decide somehow what information is needed so that
 *       we do not waste time getting stuff the user does not need.
 *)
function av_find_stream_info(ic: PAVFormatContext): cint;
  cdecl; external av__format;

(**
 * Reads a transport packet from a media file.
 *
 * This function is obsolete and should never be used.
 * Use av_read_frame() instead.
 *
 * @param s media file handle
 * @param pkt is filled
 * @return 0 if OK, AVERROR_xxx on error
 *)
function av_read_packet(s: PAVFormatContext; var pkt: TAVPacket): cint;
  cdecl; external av__format;

(**
 * Returns the next frame of a stream.
 *
 * The returned packet is valid
 * until the next av_read_frame() or until av_close_input_file() and
 * must be freed with av_free_packet. For video, the packet contains
 * exactly one frame. For audio, it contains an cint number of
 * frames if each frame has a known fixed size (e.g. PCM or ADPCM
 * data). If the audio frames have a variable size (e.g. MPEG audio),
 * then it contains one frame.
 *
 * pkt->pts, pkt->dts and pkt->duration are always set to correct
 * values in AVStream.time_base units (and guessed if the format cannot
 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
 * has B-frames, so it is better to rely on pkt->dts if you do not
 * decompress the payload.
 *
 * @return 0 if OK, < 0 on error or end of file
 *)
function av_read_frame(s: PAVFormatContext; var pkt: TAVPacket): cint;
  cdecl; external av__format;

(**
 * Seeks to the keyframe at timestamp.
 * 'timestamp' in 'stream_index'.
 * @param stream_index If stream_index is (-1), a default
 * stream is selected, and timestamp is automatically converted
 * from AV_TIME_BASE units to the stream specific time_base.
 * @param timestamp Timestamp in AVStream.time_base units
 *        or, if no stream is specified, in AV_TIME_BASE units.
 * @param flags flags which select direction and seeking mode
 * @return >= 0 on success
 *)
function av_seek_frame(s: PAVFormatContext; stream_index: cint; timestamp: cint64;
                       flags: cint): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52026000} // 52.26.0
(**
 * Seeks to timestamp ts.
 * Seeking will be done so that the point from which all active streams
 * can be presented successfully will be closest to ts and within min/max_ts.
 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
 *
 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in byte and
 * are the file position (this may not be supported by all demuxers).
 * If flags contain AVSEEK_FLAG_FRAME then all timestamps are in frames
 * in the stream with stream_index (this may not be supported by all demuxers).
 * Otherwise all timestamps are in units of the stream selected by stream_index
 * or if stream_index is -1, in AV_TIME_BASE units.
 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
 * keyframes (this may not be supported by all demuxers).
 *
 * @param stream_index index of the stream which is used as time base reference.
 * @param min_ts smallest acceptable timestamp
 * @param ts target timestamp
 * @param max_ts largest acceptable timestamp
 * @param flags flags
 * @return >=0 on success, error code otherwise
 *
 * @NOTE This is part of the new seek API which is still under construction.
 *       Thus do not use this yet. It may change at any time, do not expect
 *       ABI compatibility yet!
 *)
function avformat_seek_file(s:            PAVFormatContext;
			    stream_index: cint;
			    min_ts:       cint64;
			    ts:           cint64;
			    max_ts:       cint64;
			    flags:        cint): cint;
  cdecl; external av__format;
{$IFEND}

(**
 * Starts playing a network-based stream (e.g. RTSP stream) at the
 * current position.
 *)
function av_read_play(s: PAVFormatContext): cint;
  cdecl; external av__format;

(**
 * Pauses a network-based stream (e.g. RTSP stream).
 *
 * Use av_read_play() to resume it.
 *)
function av_read_pause(s: PAVFormatContext): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52003000} // 52.3.0
(**
 * Frees a AVFormatContext allocated by av_open_input_stream.
 * @param s context to free
 *)
procedure av_close_input_stream(s: PAVFormatContext);
  cdecl; external av__format;
{$IFEND}

(**
 * Closes a media file (but not its codecs).
 *
 * @param s media file handle
 *)
procedure av_close_input_file(s: PAVFormatContext);
  cdecl; external av__format;

(**
 * Adds a new stream to a media file.
 *
 * Can only be called in the read_header() function. If the flag
 * AVFMTCTX_NOHEADER is in the format context, then new streams
 * can be added in read_packet too.
 *
 * @param s media file handle
 * @param id file-format-dependent stream ID
 *)
function av_new_stream(s: PAVFormatContext; id: cint): PAVStream;
  cdecl; external av__format;
{$IF LIBAVFORMAT_VERSION >= 51014000} // 51.14.0
function av_new_program(s: PAVFormatContext; id: cint): PAVProgram;
  cdecl; external av__format;
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52014000} // 52.14.0
(**
 * Adds a new chapter.
 * This function is NOT part of the public API
 * and should ONLY be used by demuxers.
 *
 * @param s media file handle
 * @param id unique ID for this chapter
 * @param start chapter start time in time_base units
 * @param end chapter end time in time_base units
 * @param title chapter title
 *
 * @return AVChapter or NULL on error
 *)
function ff_new_chapter(s: PAVFormatContext; id: cint; time_base: TAVRational;
                        start, end_: cint64; title: {const} PAnsiChar): PAVChapter;
  cdecl; external av__format;
{$IFEND}

(**
 * Sets the pts for a given stream.
 *
 * @param s stream
 * @param pts_wrap_bits number of bits effectively used by the pts
 *        (used for wrap control, 33 is the value for MPEG)
 * @param pts_num numerator to convert to seconds (MPEG: 1)
 * @param pts_den denominator to convert to seconds (MPEG: 90000)
 *)
procedure av_set_pts_info(s: PAVStream; pts_wrap_bits: cint;
{$IF LIBAVFORMAT_VERSION < 52036000} // < 52.36.0
                   pts_num: cint; pts_den: cint);
{$ELSE}
                   pts_num: cuint; pts_den: cuint);
{$IFEND}
  cdecl; external av__format;

const
  AVSEEK_FLAG_BACKWARD = 1; ///< seek backward
  AVSEEK_FLAG_BYTE     = 2; ///< seeking based on position in bytes
  AVSEEK_FLAG_ANY      = 4; ///< seek to any frame, even non-keyframes
{$IF LIBAVFORMAT_VERSION >= 52037000} // >= 52.37.0
  AVSEEK_FLAG_FRAME    = 8;
{$IFEND}

function av_find_default_stream_index(s: PAVFormatContext): cint;
  cdecl; external av__format;

(**
 * Gets the index for a specific timestamp.
 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
 *                 to the timestamp which is <= the requested one, if backward
 *                 is 0, then it will be >=
 *              if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
 * @return < 0 if no such timestamp could be found
 *)
function av_index_search_timestamp(st: PAVStream; timestamp: cint64; flags: cint): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52004000} // 52.4.0
(**
 * Ensures the index uses less memory than the maximum specified in
 * AVFormatContext.max_index_size by discarding entries if it grows
 * too large.
 * This function is not part of the public API and should only be called
 * by demuxers.
 *)
procedure ff_reduce_index(s: PAVFormatContext; stream_index: cint);
  cdecl; external av__format;
{$IFEND}

(**
 * Adds an index entry into a sorted list. Updates the entry if the list
 * already contains it.
 *
 * @param timestamp timestamp in the timebase of the given stream
 *)
function av_add_index_entry(st: PAVStream; pos: cint64; timestamp: cint64;
                  size: cint; distance: cint; flags: cint): cint;
  cdecl; external av__format;

(**
 * Does a binary search using av_index_search_timestamp() and
 * AVCodec.read_timestamp().
 * This is not supposed to be called directly by a user application,
 * but by demuxers.
 * @param target_ts target timestamp in the time base of the given stream
 * @param stream_index stream number
 *)
function av_seek_frame_binary(s: PAVFormatContext; stream_index: cint;
                 target_ts: cint64; flags: cint): cint;
  cdecl; external av__format;


(**
 * Updates cur_dts of all streams based on the given timestamp and AVStream.
 *
 * Stream ref_st unchanged, others set cur_dts in their native time base.
 * Only needed for timestamp wrapping or if (dts not set and pts!=dts).
 * @param timestamp new dts expressed in time_base of param ref_st
 * @param ref_st reference stream giving time_base of param timestamp
 *)
procedure av_update_cur_dts(s: PAVFormatContext; ref_st: PAVStream;
                            timestamp: cint64);
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 51007000} // 51.7.0
type
  TReadTimestampFunc = function (pavfc: PAVFormatContext;
    arg2: cint; arg3: Pint64; arg4: cint64): cint64; cdecl;

(**
 * Does a binary search using read_timestamp().
 * This is not supposed to be called directly by a user application,
 * but by demuxers.
 * @param target_ts target timestamp in the time base of the given stream
 * @param stream_index stream number
 *)
function av_gen_search(s: PAVFormatContext; stream_index: cint;
                       target_ts: cint64; pos_min: cint64;
                       pos_max: cint64; pos_limit: cint64;
                       ts_min: cint64; ts_max: cint64;
                       flags: cint; ts_ret: Pint64;
                       read_timestamp: TReadTimestampFunc): cint64;
  cdecl; external av__format;
{$IFEND}

(* media file output *)
function av_set_parameters(s: PAVFormatContext; ap: PAVFormatParameters): cint;
  cdecl; external av__format;

(**
 * Allocates the stream private data and writes the stream header to an
 * output media file.
 *
 * @param s media file handle
 * @return 0 if OK, AVERROR_xxx on error
 *)
function av_write_header(s: PAVFormatContext): cint;
  cdecl; external av__format;

(**
 * Writes a packet to an output media file.
 *
 * The packet shall contain one audio or video frame.
 * The packet must be correctly interleaved according to the container
 * specification, if not then av_interleaved_write_frame must be used.
 *
 * @param s media file handle
 * @param pkt The packet, which contains the stream_index, buf/buf_size,
 *            dts/pts, ...
 * @return < 0 on error, = 0 if OK, 1 if end of stream wanted
 *)
function av_write_frame(s: PAVFormatContext; var pkt: TAVPacket): cint;
  cdecl; external av__format;

(**
 * Writes a packet to an output media file ensuring correct interleaving.
 *
 * The packet must contain one audio or video frame.
 * If the packets are already correctly interleaved, the application should
 * call av_write_frame() instead as it is slightly faster. It is also important
 * to keep in mind that completely non-interleaved input will need huge amounts
 * of memory to interleave with this, so it is preferable to interleave at the
 * demuxer level.
 *
 * @param s media file handle
 * @param pkt The packet, which contains the stream_index, buf/buf_size,
 *            dts/pts, ...
 * @return < 0 on error, = 0 if OK, 1 if end of stream wanted
 *)
function av_interleaved_write_frame(s: PAVFormatContext; var pkt: TAVPacket): cint;
  cdecl; external av__format;

(**
 * Interleaves a packet per dts in an output media file.
 *
 * Packets with pkt->destruct == av_destruct_packet will be freed inside this
 * function, so they cannot be used after it. Note that calling av_free_packet()
 * on them is still safe.
 *
 * @param s media file handle
 * @param out the interleaved packet will be output here
 * @param in the input packet
 * @param flush 1 if no further packets are available as input and all
 *              remaining packets should be output
 * @return 1 if a packet was output, 0 if no packet could be output,
 *         < 0 if an error occurred
 *)
function av_interleave_packet_per_dts(s: PAVFormatContext; _out: PAVPacket;
                                      pkt: PAVPacket; flush: cint): cint;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION >= 52025000} // 52.25.0
(**
 * Add packet to AVFormatContext->packet_buffer list, determining its
 * interleaved position using compare() function argument.
 *
 * This function is not part of the public API and should only be called
 * by muxers using their own interleave function.
 *)
{
procedure ff_interleave_add_packet(s:   PAVFormatContext;
                                   pkt: PAVPacket;
		   compare: function(para1: PAVFormatContext;
				     para2: PAVPacket;
				     para3: PAVPacket): cint);
  cdecl; external av__format;
}
{$IFEND}

(**
 * Writes the stream trailer to an output media file and frees the
 * file private data.
 *
 * May only be called after a successful call to av_write_header.
 *
 * @param s media file handle
 * @return 0 if OK, AVERROR_xxx on error
 *)
function av_write_trailer(s: pAVFormatContext): cint;
  cdecl; external av__format;

procedure dump_format(ic: PAVFormatContext; index: cint; url: PAnsiChar;
               is_output: cint);
  cdecl; external av__format;

(**
 * Parses width and height out of string str.
 * @deprecated Use av_parse_video_frame_size instead.
 *)
function parse_image_size(width_ptr: PCint; height_ptr: PCint;
                          str: PAnsiChar): cint;
  cdecl; external av__format; deprecated;

{$IF LIBAVFORMAT_VERSION_MAJOR < 53}
(**
 * Converts framerate from a string to a fraction.
 * @deprecated Use av_parse_video_frame_rate instead.
 *)
function parse_frame_rate(frame_rate: PCint; frame_rate_base: PCint;
                          arg: PByteArray): cint;
  cdecl; external av__format; deprecated;
{$IFEND}

(**
 * Parses datestr and returns a corresponding number of microseconds.
 * @param datestr String representing a date or a duration.
 * - If a date the syntax is:
 * @code
 *  [{YYYY-MM-DD|YYYYMMDD}]{T| }{HH[:MM[:SS[.m...]]][Z]|HH[MM[SS[.m...]]][Z]}
 * @endcode
 * Time is localtime unless Z is appended, in which case it is
 * interpreted as UTC.
 * If the year-month-day part is not specified it takes the current
 * year-month-day.
 * Returns the number of microseconds since 1st of January, 1970 up to
 * the time of the parsed date or INT64_MIN if datestr cannot be
 * successfully parsed.
 * - If a duration the syntax is:
 * @code
 *  [-]HH[:MM[:SS[.m...]]]
 *  [-]S+[.m...]
 * @endcode
 * Returns the number of microseconds contained in a time interval
 * with the specified duration or INT64_MIN if datestr cannot be
 * successfully parsed.
 * @param duration Flag which tells how to interpret datestr, if
 * not zero datestr is interpreted as a duration, otherwise as a
 * date.
 *)
function parse_date(datestr: PAnsiChar; duration: cint): cint64;
  cdecl; external av__format;

(** Gets the current time in microseconds. *)
function av_gettime(): cint64;
  cdecl; external av__format;

(* ffm-specific for ffserver *)
const
  FFM_PACKET_SIZE = 4096;

function ffm_read_write_index(fd: cint): cint64;
  cdecl; external av__format;

{$IF LIBAVFORMAT_VERSION < 52027000} // 52.27.0
procedure ffm_write_write_index(fd: cint; pos: cint64);
{$ELSE}
function ffm_write_write_index(fd: cint; pos: cint64): cint;
{$IFEND}
  cdecl; external av__format;

procedure ffm_set_write_index(s: PAVFormatContext; pos: cint64; file_size: cint64);
  cdecl; external av__format;

(**
 * Attempts to find a specific tag in a URL.
 *
 * syntax: '?tag1=val1&tag2=val2...'. Little URL decoding is done.
 * Return 1 if found.
 *)
function find_info_tag(arg: PAnsiChar; arg_size: cint; tag1: PAnsiChar; info: PAnsiChar): cint;
  cdecl; external av__format;

(**
 * Returns in 'buf' the path with '%d' replaced by a number.
 *
 * Also handles the '%0nd' format where 'n' is the total number
 * of digits and '%%'.
 *
 * @param buf destination buffer
 * @param buf_size destination buffer size
 * @param path numbered sequence string
 * @param number frame number
 * @return 0 if OK, -1 on format error
 *)
function av_get_frame_filename(buf: PAnsiChar; buf_size: cint;
                               path: PAnsiChar; number: cint): cint;
  cdecl; external av__format
  {$IF LIBAVFORMAT_VERSION <= 50006000} // 50.6.0
  name 'get_frame_filename'
  {$IFEND};

(**
 * Checks whether filename actually is a numbered sequence generator.
 *
 * @param filename possible numbered sequence string
 * @return 1 if a valid numbered sequence string, 0 otherwise
 *)
function av_filename_number_test(filename: PAnsiChar): cint;
  cdecl; external av__format
  {$IF LIBAVFORMAT_VERSION <= 50006000} // 50.6.0
  name 'filename_number_test'
  {$IFEND};

{$IF LIBAVFORMAT_VERSION >= 51012002} // 51.12.2
(**
 * Generates an SDP for an RTP session.
 *
 * @param ac array of AVFormatContexts describing the RTP streams. If the
 *           array is composed by only one context, such context can contain
 *           multiple AVStreams (one AVStream per RTP stream). Otherwise,
 *           all the contexts in the array (an AVCodecContext per RTP stream)
 *           must contain only one AVStream.
 * @param n_files number of AVCodecContexts contained in ac
 * @param buff buffer where the SDP will be stored (must be allocated by
 *             the caller)
 * @param size the size of the buffer
 * @return 0 if OK, AVERROR_xxx on error
 *)
function avf_sdp_create(ac: PPAVFormatContext; n_files: cint; buff: PByteArray; size: cint): cint;
  cdecl; external av__format;
{$IFEND}

{$IF LIBAVFORMAT_VERSION >= 52060000} // 52.60.0
(**
 * Returns a positive value if the given filename has one of the given
 * extensions, 0 otherwise.
 *
 * @param extensions a comma-separated list of filename extensions
 *)
function av_match_ext(filename: {const} Pchar; extensions: {const} Pchar): cint;
  cdecl; external av__format;
{$IFEND}

implementation

{$IF LIBAVFORMAT_VERSION < 51012002} // 51.12.2
procedure av_init_packet(var pkt: TAVPacket);
begin
  with pkt do begin
    pts   := AV_NOPTS_VALUE;
    dts   := AV_NOPTS_VALUE;
    pos   := -1;
    duration := 0;
    flags := 0;
    stream_index := 0;
    destruct := @av_destruct_packet_nofree
  end
end;
{$IFEND}

{$IF LIBAVFORMAT_VERSION < 52032000} // < 52.32.0
procedure av_free_packet(pkt: PAVPacket);
begin
  if ((pkt <> nil) and (@pkt^.destruct <> nil)) then
    pkt^.destruct(pkt);
end;
{$IFEND}

end.