audio code replaced by (yet pseudo-)plugin

git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/branches/experimental@2687 b956fd51-792f-4845-bead-9b4dfca2ff2c

2 files changed, 158 insertions, 956 deletions

diff --git a/mediaplugin/src/media/UAudioDecoder_FFmpeg.pas b/mediaplugin/src/media/UAudioDecoder_FFmpeg.pas
index b44c7b11..9c734786 100644
--- a/mediaplugin/src/media/UAudioDecoder_FFmpeg.pas
+++ b/mediaplugin/src/media/UAudioDecoder_FFmpeg.pas
@@ -44,120 +44,26 @@ interface
 
 {$I switches.inc}
 
-// show FFmpeg specific debug output
-{.$DEFINE DebugFFmpegDecode}
-
-// FFmpeg is very verbose and shows a bunch of errors.
-// Those errors (they can be considered as warnings by us) can be ignored
-// as they do not give any useful information.
-// There is no solution to fix this except for turning them off.
-{.$DEFINE EnableFFmpegErrorOutput}
-
 implementation
 
 uses
-  SDL, // SDL redefines some base types -> include before SysUtils to ignore them
+  ctypes,
   Classes,
-  Math,
   SysUtils,
-  avcodec,
-  avformat,
-  avutil,
-  avio,
-  mathematics, // used for av_rescale_q
-  rational,
+  UMediaPlugin,
   UMusic,
   UIni,
   UMain,
-  UMediaCore_FFmpeg,
   ULog,
-  UCommon,
-  UConfig,
   UPath;
 
-const
-  MAX_AUDIOQ_SIZE = (5 * 16 * 1024);
-
-const
-  // TODO: The factor 3/2 might not be necessary as we do not need extra
-  // space for synchronizing as in the tutorial.
-  AUDIO_BUFFER_SIZE = (AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) div 2;
-
 type
   TFFmpegDecodeStream = class(TAudioDecodeStream)
     private
-      fStateLock:   PSDL_Mutex;
-
-      fEOFState:   boolean; // end-of-stream flag (locked by StateLock)
-      fErrorState: boolean; // error flag (locked by StateLock)
-
-      fQuitRequest: boolean; // (locked by StateLock)
-      fParserIdleCond: PSDL_Cond;
-
-      // parser pause/resume data
-      fParserLocked:            boolean;
-      fParserPauseRequestCount: integer;
-      fParserUnlockedCond:      PSDL_Cond;
-      fParserResumeCond:        PSDL_Cond;
-
-      fSeekRequest: boolean; // (locked by StateLock)
-      fSeekFlags:   integer; // (locked by StateLock)
-      fSeekPos:     double;    // stream position to seek for (in secs) (locked by StateLock)
-      fSeekFlush:   boolean;   // true if the buffers should be flushed after seeking (locked by StateLock)
-      SeekFinishedCond: PSDL_Cond;
-
-      fLoop: boolean; // (locked by StateLock)
-
-      fParseThread: PSDL_Thread;
-      fPacketQueue: TPacketQueue;
-
-      fFormatInfo: TAudioFormatInfo;
-
-      // FFmpeg specific data
-      fFormatCtx: PAVFormatContext;
-      fCodecCtx:  PAVCodecContext;
-      fCodec:     PAVCodec;
-
-      fAudioStreamIndex: integer;
-      fAudioStream: PAVStream;
-      fAudioStreamPos: double; // stream position in seconds (locked by DecoderLock)
-
-      // decoder pause/resume data
-      fDecoderLocked:            boolean;
-      fDecoderPauseRequestCount: integer;
-      fDecoderUnlockedCond:      PSDL_Cond;
-      fDecoderResumeCond:        PSDL_Cond;
-
-      // state-vars for DecodeFrame (locked by DecoderLock)
-      fAudioPaket:        TAVPacket;
-      fAudioPaketData:    PByteArray;
-      fAudioPaketSize:    integer;
-      fAudioPaketSilence: integer; // number of bytes of silence to return
-
-      // state-vars for AudioCallback (locked by DecoderLock)
-      fAudioBufferPos:  integer;
-      fAudioBufferSize: integer;
-      fAudioBuffer:     PByteArray;
-
       fFilename: IPath;
+      fStream: PDecodeStream;
+      fFormatInfo: TAudioFormatInfo;
 
-      procedure SetPositionIntern(Time: real; Flush: boolean; Blocking: boolean);
-      procedure SetEOF(State: boolean);   {$IFDEF HasInline}inline;{$ENDIF}
-      procedure SetError(State: boolean); {$IFDEF HasInline}inline;{$ENDIF}
-      function IsSeeking(): boolean;
-      function IsQuit(): boolean;
-
-      procedure Reset();
-
-      procedure Parse();
-      function ParseLoop(): boolean;
-      procedure PauseParser();
-      procedure ResumeParser();
-
-      function DecodeFrame(Buffer: PByteArray; BufferSize: integer): integer;
-      procedure FlushCodecBuffers();
-      procedure PauseDecoder();
-      procedure ResumeDecoder();
     public
       constructor Create();
       destructor Destroy(); override;
@@ -187,68 +93,12 @@ type
       function Open(const Filename: IPath): TAudioDecodeStream;
   end;
 
-var
-  FFmpegCore: TMediaCore_FFmpeg;
-
-function ParseThreadMain(Data: Pointer): integer; cdecl; forward;
-
-
 { TFFmpegDecodeStream }
 
 constructor TFFmpegDecodeStream.Create();
 begin
   inherited Create();
-
-  fStateLock := SDL_CreateMutex();
-  fParserUnlockedCond := SDL_CreateCond();
-  fParserResumeCond := SDL_CreateCond();
-  fParserIdleCond := SDL_CreateCond();
-  SeekFinishedCond := SDL_CreateCond();
-  fDecoderUnlockedCond := SDL_CreateCond();
-  fDecoderResumeCond := SDL_CreateCond();
-
-  // according to the documentation of avcodec_decode_audio(2), sample-data
-  // should be aligned on a 16 byte boundary. Otherwise internal calls
-  // (e.g. to SSE or Altivec operations) might fail or lack performance on some
-  // CPUs. Although GetMem() in Delphi and FPC seems to use a 16 byte or higher
-  // alignment for buffers of this size (alignment depends on the size of the
-  // requested buffer), we will set the alignment explicitly as the minimum
-  // alignment used by Delphi and FPC is on an 8 byte boundary.
-  // 
-  // Note: AudioBuffer was previously defined as a field of type TAudioBuffer
-  // (array[0..AUDIO_BUFFER_SIZE-1] of byte) and hence statically allocated.
-  // Fields of records are aligned different to memory allocated with GetMem(),
-  // aligning depending on the type but will be at least 2 bytes.
-  // AudioBuffer was not aligned to a 16 byte boundary. The {$ALIGN x} directive
-  // was not applicable as Delphi in contrast to FPC provides at most 8 byte
-  // alignment ({$ALIGN 16} is not supported) by this directive.
-  fAudioBuffer := GetAlignedMem(AUDIO_BUFFER_SIZE, 16);
-
-  Reset();
-end;
-
-procedure TFFmpegDecodeStream.Reset();
-begin
-  fParseThread := nil;
-
-  fEOFState := false;
-  fErrorState := false;
-  fLoop := false;
-  fQuitRequest := false;
-
-  fAudioPaketData := nil;
-  fAudioPaketSize := 0;
-  fAudioPaketSilence := 0;
-
-  fAudioBufferPos := 0;
-  fAudioBufferSize := 0;
-
-  fParserLocked := false;
-  fParserPauseRequestCount := 0;
-  fDecoderLocked := false;
-  fDecoderPauseRequestCount := 0;
-
-  FillChar(fAudioPaket, SizeOf(TAVPacket), 0);
+  fFilename := PATH_NONE;
 end;
 
 {*
@@ -257,201 +107,46 @@ end;
 destructor TFFmpegDecodeStream.Destroy();
 begin
   Close();
-
-  SDL_DestroyMutex(fStateLock);
-  SDL_DestroyCond(fParserUnlockedCond);
-  SDL_DestroyCond(fParserResumeCond);
-  SDL_DestroyCond(fParserIdleCond);
-  SDL_DestroyCond(SeekFinishedCond);
-  SDL_DestroyCond(fDecoderUnlockedCond);
-  SDL_DestroyCond(fDecoderResumeCond);
-
-  FreeAlignedMem(fAudioBuffer);
-
   inherited;
 end;
 
 function TFFmpegDecodeStream.Open(const Filename: IPath): boolean;
 var
-  SampleFormat: TAudioSampleFormat;
-  AVResult: integer;
+  Info: TCAudioFormatInfo;
 begin
   Result := false;
 
   Close();
-  Reset();
-
-  if (not Filename.IsFile) then
-  begin
-    Log.LogError('Audio-file does not exist: "' + Filename.ToNative + '"', 'UAudio_FFmpeg');
-    Exit;
-  end;
-
-  Self.fFilename := Filename;
-
-  // use custom 'ufile' protocol for UTF-8 support
-  if (av_open_input_file(fFormatCtx, PAnsiChar('ufile:'+FileName.ToUTF8), nil, 0, nil) <> 0) then
-  begin
-    Log.LogError('av_open_input_file failed: "' + Filename.ToNative + '"', 'UAudio_FFmpeg');
-    Exit;
-  end;
-
-  // generate PTS values if they do not exist
-  fFormatCtx^.flags := fFormatCtx^.flags or AVFMT_FLAG_GENPTS;
-
-  // retrieve stream information
-  if (av_find_stream_info(fFormatCtx) < 0) then
-  begin
-    Log.LogError('av_find_stream_info failed: "' + Filename.ToNative + '"', 'UAudio_FFmpeg');
-    Close();
-    Exit;
-  end;
-
-  // FIXME: hack used by ffplay. Maybe should not use url_feof() to test for the end
-  fFormatCtx^.pb.eof_reached := 0;
-
-  {$IFDEF DebugFFmpegDecode}
-  dump_format(fFormatCtx, 0, PAnsiChar(Filename.ToNative), 0);
-  {$ENDIF}
 
-  fAudioStreamIndex := FFmpegCore.FindAudioStreamIndex(fFormatCtx);
-  if (fAudioStreamIndex < 0) then
-  begin
-    Log.LogError('FindAudioStreamIndex: No Audio-stream found "' + Filename.ToNative + '"', 'UAudio_FFmpeg');
-    Close();
-    Exit;
-  end;
-
-  //Log.LogStatus('AudioStreamIndex is: '+ inttostr(ffmpegStreamID), 'UAudio_FFmpeg');
-
-  fAudioStream := fFormatCtx.streams[fAudioStreamIndex];
-  fAudioStreamPos := 0;
-  fCodecCtx := fAudioStream^.codec;
-
-  // TODO: should we use this or not? Should we allow 5.1 channel audio?
-  (*
-  {$IF LIBAVCODEC_VERSION >= 51042000}
-  if (CodecCtx^.channels > 0) then
-    CodecCtx^.request_channels := Min(2, CodecCtx^.channels)
-  else
-    CodecCtx^.request_channels := 2;
-  {$IFEND}
-  *)
-
-  fCodec := avcodec_find_decoder(fCodecCtx^.codec_id);
-  if (fCodec = nil) then
-  begin
-    Log.LogError('Unsupported codec!', 'UAudio_FFmpeg');
-    fCodecCtx := nil;
-    Close();
-    Exit;
-  end;
-
-  // set debug options
-  fCodecCtx^.debug_mv := 0;
-  fCodecCtx^.debug := 0;
-
-  // detect bug-workarounds automatically
-  fCodecCtx^.workaround_bugs := FF_BUG_AUTODETECT;
-  // error resilience strategy (careful/compliant/agressive/very_aggressive)
-  //CodecCtx^.error_resilience := FF_ER_CAREFUL; //FF_ER_COMPLIANT;
-  // allow non spec compliant speedup tricks.
-  //CodecCtx^.flags2 := CodecCtx^.flags2 or CODEC_FLAG2_FAST;
-
-  // Note: avcodec_open() and avcodec_close() are not thread-safe and will
-  // fail if called concurrently by different threads.
-  FFmpegCore.LockAVCodec();
-  try
-    AVResult := avcodec_open(fCodecCtx, fCodec);
-  finally
-    FFmpegCore.UnlockAVCodec();
-  end;
-  if (AVResult < 0) then
-  begin
-    Log.LogError('avcodec_open failed!', 'UAudio_FFmpeg');
-    Close();
+  fStream := DecodeStream_open(PChar(Filename.ToUTF8()));
+  if (fStream = nil) then
     Exit;
-  end;
 
-  // now initialize the audio-format
+  fFilename := Filename;
 
-  if (not FFmpegCore.ConvertFFmpegToAudioFormat(fCodecCtx^.sample_fmt, SampleFormat)) then
-  begin
-    // try standard format
-    SampleFormat := asfS16;
-  end;
-  if fCodecCtx^.channels > 255 then
-    Log.LogStatus('Error: CodecCtx^.channels > 255', 'TFFmpegDecodeStream.Open');
+  DecodeStream_getAudioFormatInfo(fStream, Info);
   fFormatInfo := TAudioFormatInfo.Create(
-    byte(fCodecCtx^.channels),
-    fCodecCtx^.sample_rate,
-    SampleFormat
+    Info.channels,
+    Info.sampleRate,
+    TAudioSampleFormat(Info.format)
   );
 
-  fPacketQueue := TPacketQueue.Create();
-
-  // finally start the decode thread
-  fParseThread := SDL_CreateThread(@ParseThreadMain, Self);
-
   Result := true;
 end;
 
 procedure TFFmpegDecodeStream.Close();
-var
-  ThreadResult: integer;
 begin
-  // wake threads waiting for packet-queue data
-  // Note: normally, there are no waiting threads. If there were waiting
-  // ones, they would block the audio-callback thread.
-  if (assigned(fPacketQueue)) then
-    fPacketQueue.Abort();
-
-  // send quit request (to parse-thread etc)
-  SDL_mutexP(fStateLock);
-  fQuitRequest := true;
-  SDL_CondBroadcast(fParserIdleCond);
-  SDL_mutexV(fStateLock);
-
-  // abort parse-thread
-  if (fParseThread <> nil) then
-  begin
-    // and wait until it terminates
-    SDL_WaitThread(fParseThread, ThreadResult);
-    fParseThread := nil;
-  end;
-
-  // Close the codec
-  if (fCodecCtx <> nil) then
-  begin
-    // avcodec_close() is not thread-safe
-    FFmpegCore.LockAVCodec();
-    try
-      avcodec_close(fCodecCtx);
-    finally
-      FFmpegCore.UnlockAVCodec();
-    end;
-    fCodecCtx := nil;
-  end;
-
-  // Close the video file
-  if (fFormatCtx <> nil) then
+  Self.fFilename := PATH_NONE;
+  if (fStream <> nil) then
   begin
-    av_close_input_file(fFormatCtx);
-    fFormatCtx := nil;
+    DecodeStream_close(fStream);
+    fStream := nil;
   end;
-
-  PerformOnClose();
-  
-  FreeAndNil(fPacketQueue);
-  FreeAndNil(fFormatInfo);
 end;
 
 function TFFmpegDecodeStream.GetLength(): real;
 begin
-  // do not forget to consider the start_time value here
-  // there is a type size mismatch warnign because start_time and duration are cint64.
-  // So, in principle there could be an overflow when doing the sum.
-  Result := (fFormatCtx^.start_time + fFormatCtx^.duration) / AV_TIME_BASE;
+  Result := DecodeStream_getLength(fStream);
 end;
 
 function TFFmpegDecodeStream.GetAudioFormatInfo(): TAudioFormatInfo;
@@ -461,642 +156,37 @@ end;
 
 function TFFmpegDecodeStream.IsEOF(): boolean;
 begin
-  SDL_mutexP(fStateLock);
-  Result := fEOFState;
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.SetEOF(State: boolean);
-begin
-  SDL_mutexP(fStateLock);
-  fEOFState := State;
-  SDL_mutexV(fStateLock);
+  Result := DecodeStream_isEOF(fStream);
 end;
 
 function TFFmpegDecodeStream.IsError(): boolean;
 begin
-  SDL_mutexP(fStateLock);
-  Result := fErrorState;
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.SetError(State: boolean);
-begin
-  SDL_mutexP(fStateLock);
-  fErrorState := State;
-  SDL_mutexV(fStateLock);
-end;
-
-function TFFmpegDecodeStream.IsSeeking(): boolean;
-begin
-  SDL_mutexP(fStateLock);
-  Result := fSeekRequest;
-  SDL_mutexV(fStateLock);
-end;
-
-function TFFmpegDecodeStream.IsQuit(): boolean;
-begin
-  SDL_mutexP(fStateLock);
-  Result := fQuitRequest;
-  SDL_mutexV(fStateLock);
+  Result := DecodeStream_isError(fStream);
 end;
 
 function TFFmpegDecodeStream.GetPosition(): real;
-var
-  BufferSizeSec: double;
 begin
-  PauseDecoder();
-
-  // ReadData() does not return all of the buffer retrieved by DecodeFrame().
-  // Determine the size of the unused part of the decode-buffer.
-  BufferSizeSec := (fAudioBufferSize - fAudioBufferPos) /
-                   fFormatInfo.BytesPerSec;
-
-  // subtract the size of unused buffer-data from the audio clock.
-  Result := fAudioStreamPos - BufferSizeSec;
-
-  ResumeDecoder();
+  Result := DecodeStream_getPosition(fStream);
 end;
 
 procedure TFFmpegDecodeStream.SetPosition(Time: real);
 begin
-  SetPositionIntern(Time, true, true);
+  DecodeStream_setPosition(fStream, Time);
 end;
 
 function TFFmpegDecodeStream.GetLoop(): boolean;
 begin
-  SDL_mutexP(fStateLock);
-  Result := fLoop;
-  SDL_mutexV(fStateLock);
+  Result := DecodeStream_getLoop(fStream);
 end;
 
 procedure TFFmpegDecodeStream.SetLoop(Enabled: boolean);
 begin
-  SDL_mutexP(fStateLock);
-  fLoop := Enabled;
-  SDL_mutexV(fStateLock);
-end;
-
-
-(********************************************
- * Parser section
- ********************************************)
-
-procedure TFFmpegDecodeStream.PauseParser();
-begin
-  if (SDL_ThreadID() = fParseThread.threadid) then
-    Exit;
-    
-  SDL_mutexP(fStateLock);
-  Inc(fParserPauseRequestCount);
-  while (fParserLocked) do
-    SDL_CondWait(fParserUnlockedCond, fStateLock);
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.ResumeParser();
-begin
-  if (SDL_ThreadID() = fParseThread.threadid) then
-    Exit;
-
-  SDL_mutexP(fStateLock);
-  Dec(fParserPauseRequestCount);
-  SDL_CondSignal(fParserResumeCond);
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.SetPositionIntern(Time: real; Flush: boolean; Blocking: boolean);
-begin
-  // - Pause the parser first to prevent it from putting obsolete packages
-  //   into the queue after the queue was flushed and before seeking is done.
-  //   Otherwise we will hear fragments of old data, if the stream was seeked
-  //   in stopped mode and resumed afterwards (applies to non-blocking mode only).
-  // - Pause the decoder to avoid race-condition that might occur otherwise.
-  // - Last lock the state lock because we are manipulating some shared state-vars.
-  PauseParser();
-  PauseDecoder();
-  SDL_mutexP(fStateLock);
-  try
-    fEOFState := false;
-    fErrorState := false;
-
-    // do not seek if we are already at the correct position.
-    // This is important especially for seeking to position 0 if we already are
-    // at the beginning. Although seeking with AVSEEK_FLAG_BACKWARD for pos 0 works,
-    // it is still a bit choppy (although much better than w/o AVSEEK_FLAG_BACKWARD).
-    if (Time = fAudioStreamPos) then
-      Exit;    
-
-    // configure seek parameters
-    fSeekPos := Time;
-    fSeekFlush := Flush;
-    fSeekFlags := AVSEEK_FLAG_ANY;
-    fSeekRequest := true;
-
-    // Note: the BACKWARD-flag seeks to the first position <= the position
-    // searched for. Otherwise e.g. position 0 might not be seeked correct.
-    // For some reason ffmpeg sometimes doesn't use position 0 but the key-frame
-    // following. In streams with few key-frames (like many flv-files) the next
-    // key-frame after 0 might be 5secs ahead.
-    if (Time <= fAudioStreamPos) then
-      fSeekFlags := fSeekFlags or AVSEEK_FLAG_BACKWARD;
-
-    // send a reuse signal in case the parser was stopped (e.g. because of an EOF)
-    SDL_CondSignal(fParserIdleCond);
-  finally
-    SDL_mutexV(fStateLock);
-    ResumeDecoder();
-    ResumeParser();
-  end;
-
-  // in blocking mode, wait until seeking is done
-  if (Blocking) then
-  begin
-    SDL_mutexP(fStateLock);
-    while (fSeekRequest) do
-      SDL_CondWait(SeekFinishedCond, fStateLock);
-    SDL_mutexV(fStateLock);
-  end;
-end;
-
-function ParseThreadMain(Data: Pointer): integer; cdecl;
-var
-  Stream: TFFmpegDecodeStream;
-begin
-  Stream := TFFmpegDecodeStream(Data);
-  if (Stream <> nil) then
-    Stream.Parse();
-  Result := 0;
-end;
-
-procedure TFFmpegDecodeStream.Parse();
-begin
-  // reuse thread as long as the stream is not terminated
-  while (ParseLoop()) do
-  begin
-    // wait for reuse or destruction of stream
-    SDL_mutexP(fStateLock);
-    while (not (fSeekRequest or fQuitRequest)) do
-      SDL_CondWait(fParserIdleCond, fStateLock);
-    SDL_mutexV(fStateLock);
-  end;
-end;
-
-(**
- * Parser main loop.
- * Will not return until parsing of the stream is finished.
- * Reasons for the parser to return are:
- * - the end-of-file is reached
- * - an error occured
- * - the stream was quited (received a quit-request)
- * Returns true if the stream can be resumed or false if the stream has to
- * be terminated.
- *)
-function TFFmpegDecodeStream.ParseLoop(): boolean;
-var
-  Packet: TAVPacket;
-  SeekTarget: int64;
-  ByteIOCtx: PByteIOContext;
-  ErrorCode: integer;
-  StartSilence: double;       // duration of silence at start of stream
-  StartSilencePtr: PDouble;  // pointer for the EMPTY status packet 
-
-  // Note: pthreads wakes threads waiting on a mutex in the order of their
-  // priority and not in FIFO order. SDL does not provide any option to
-  // control priorities. This might (and already did) starve threads waiting
-  // on the mutex (e.g. SetPosition) making usdx look like it was froozen.
-  // Instead of simply locking the critical section we set a ParserLocked flag
-  // instead and give priority to the threads requesting the parser to pause.
-  procedure LockParser();
-  begin
-    SDL_mutexP(fStateLock);
-    while (fParserPauseRequestCount > 0) do
-      SDL_CondWait(fParserResumeCond, fStateLock);
-    fParserLocked := true;
-    SDL_mutexV(fStateLock);
-  end;
-
-  procedure UnlockParser();
-  begin
-    SDL_mutexP(fStateLock);
-    fParserLocked := false;
-    SDL_CondBroadcast(fParserUnlockedCond);
-    SDL_mutexV(fStateLock);
-  end;
-
-begin
-  Result := true;
-
-  while (true) do
-  begin
-    LockParser();
-    try
-
-      if (IsQuit()) then
-      begin
-        Result := false;
-        Exit;
-      end;
-
-      // handle seek-request (Note: no need to lock SeekRequest here)
-      if (fSeekRequest) then
-      begin
-        // first try: seek on the audio stream
-        SeekTarget := Round(fSeekPos / av_q2d(fAudioStream^.time_base));
-        StartSilence := 0;
-        if (SeekTarget < fAudioStream^.start_time) then
-          StartSilence := (fAudioStream^.start_time - SeekTarget) * av_q2d(fAudioStream^.time_base);
-        ErrorCode := av_seek_frame(fFormatCtx, fAudioStreamIndex, SeekTarget, fSeekFlags);
-
-        if (ErrorCode < 0) then
-        begin
-          // second try: seek on the default stream (necessary for flv-videos and some ogg-files)
-          SeekTarget := Round(fSeekPos * AV_TIME_BASE);
-          StartSilence := 0;
-          if (SeekTarget < fFormatCtx^.start_time) then
-            StartSilence := (fFormatCtx^.start_time - SeekTarget) / AV_TIME_BASE;
-          ErrorCode := av_seek_frame(fFormatCtx, -1, SeekTarget, fSeekFlags);
-        end;
-
-        // pause decoder and lock state (keep the lock-order to avoid deadlocks).
-        // Note that the decoder does not block in the packet-queue in seeking state,
-        // so locking the decoder here does not cause a dead-lock.
-        PauseDecoder();
-        SDL_mutexP(fStateLock);
-        try
-          if (ErrorCode < 0) then
-          begin
-            // seeking failed
-            fErrorState := true;
-            Log.LogError('Seek Error in "'+fFormatCtx^.filename+'"', 'UAudioDecoder_FFmpeg');
-          end
-          else
-          begin
-            if (fSeekFlush) then
-            begin
-              // flush queue (we will send a Flush-Packet when seeking is finished)
-              fPacketQueue.Flush();
-
-              // flush the decode buffers
-              fAudioBufferSize := 0;
-              fAudioBufferPos := 0;
-              fAudioPaketSize := 0;
-              fAudioPaketSilence := 0;
-              FlushCodecBuffers();
-              
-              // Set preliminary stream position. The position will be set to
-              // the correct value as soon as the first packet is decoded.
-              fAudioStreamPos := fSeekPos;
-            end
-            else
-            begin
-              // request avcodec buffer flush
-              fPacketQueue.PutStatus(PKT_STATUS_FLAG_FLUSH, nil);
-            end;
-
-            // fill the gap between position 0 and start_time with silence
-            // but not if we are in loop mode
-            if ((StartSilence > 0) and (not fLoop)) then
-            begin
-              GetMem(StartSilencePtr, SizeOf(StartSilence));
-              StartSilencePtr^ := StartSilence;
-              fPacketQueue.PutStatus(PKT_STATUS_FLAG_EMPTY, StartSilencePtr);
-            end;
-          end;
-
-          fSeekRequest := false;
-          SDL_CondBroadcast(SeekFinishedCond);
-        finally
-          SDL_mutexV(fStateLock);
-          ResumeDecoder();
-        end;
-      end;
-
-      if (fPacketQueue.GetSize() > MAX_AUDIOQ_SIZE) then
-      begin
-        SDL_Delay(10);
-        Continue;
-      end;
-
-      if (av_read_frame(fFormatCtx, Packet) < 0) then
-      begin
-        // failed to read a frame, check reason
-        {$IF (LIBAVFORMAT_VERSION_MAJOR >= 52)}
-        ByteIOCtx := fFormatCtx^.pb;
-        {$ELSE}
-        ByteIOCtx := @fFormatCtx^.pb;
-        {$IFEND}
-
-        // check for end-of-file (eof is not an error)
-        if (url_feof(ByteIOCtx) <> 0) then
-        begin
-          if (GetLoop()) then
-          begin
-            // rewind stream (but do not flush)
-            SetPositionIntern(0, false, false);
-            Continue;
-          end
-          else
-          begin
-            // signal end-of-file
-            fPacketQueue.PutStatus(PKT_STATUS_FLAG_EOF, nil);
-            Exit;
-          end;
-        end;
-
-        // check for errors
-        if (url_ferror(ByteIOCtx) <> 0) then
-        begin
-          // an error occured -> abort and wait for repositioning or termination
-          fPacketQueue.PutStatus(PKT_STATUS_FLAG_ERROR, nil);
-          Exit;
-        end;
-
-        // url_feof() does not detect an EOF for some files
-        // so we have to do it this way.
-        if ((fFormatCtx^.file_size <> 0) and
-            (ByteIOCtx^.pos >= fFormatCtx^.file_size)) then
-        begin
-          fPacketQueue.PutStatus(PKT_STATUS_FLAG_EOF, nil);
-          Exit;
-        end;
-
-        // unknown error occured, exit
-        fPacketQueue.PutStatus(PKT_STATUS_FLAG_ERROR, nil);
-        Exit;
-      end;
-
-      if (Packet.stream_index = fAudioStreamIndex) then
-        fPacketQueue.Put(@Packet)
-      else
-        av_free_packet(@Packet);
-
-    finally
-      UnlockParser();
-    end;
-  end;
-end;
-
-
-(********************************************
- * Decoder section
- ********************************************)
-
-procedure TFFmpegDecodeStream.PauseDecoder();
-begin
-  SDL_mutexP(fStateLock);
-  Inc(fDecoderPauseRequestCount);
-  while (fDecoderLocked) do
-    SDL_CondWait(fDecoderUnlockedCond, fStateLock);
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.ResumeDecoder();
-begin
-  SDL_mutexP(fStateLock);
-  Dec(fDecoderPauseRequestCount);
-  SDL_CondSignal(fDecoderResumeCond);
-  SDL_mutexV(fStateLock);
-end;
-
-procedure TFFmpegDecodeStream.FlushCodecBuffers();
-begin
-  // if no flush operation is specified, avcodec_flush_buffers will not do anything.
-  if (@fCodecCtx.codec.flush <> nil) then
-  begin
-    // flush buffers used by avcodec_decode_audio, etc.
-    avcodec_flush_buffers(fCodecCtx);
-  end
-  else
-  begin
-    // we need a Workaround to avoid plopping noise with ogg-vorbis and
-    // mp3 (in older versions of FFmpeg).
-    // We will just reopen the codec.
-    FFmpegCore.LockAVCodec();
-    try
-      avcodec_close(fCodecCtx);
-      avcodec_open(fCodecCtx, fCodec);
-    finally
-      FFmpegCore.UnlockAVCodec();
-    end;
-  end;
-end;
-
-function TFFmpegDecodeStream.DecodeFrame(Buffer: PByteArray; BufferSize: integer): integer;
-var
-  PaketDecodedSize: integer; // size of packet data used for decoding
-  DataSize: integer;         // size of output data decoded by FFmpeg
-  BlockQueue: boolean;
-  SilenceDuration: double;
-  {$IFDEF DebugFFmpegDecode}
-  TmpPos: double;
-  {$ENDIF}
-begin
-  Result := -1;
-
-  if (EOF) then
-    Exit;
-
-  while(true) do
-  begin
-    // for titles with start_time > 0 we have to generate silence
-    // until we reach the pts of the first data packet.
-    if (fAudioPaketSilence > 0) then
-    begin
-      DataSize := Min(fAudioPaketSilence, BufferSize);
-      FillChar(Buffer[0], DataSize, 0);
-      Dec(fAudioPaketSilence, DataSize);
-      fAudioStreamPos := fAudioStreamPos + DataSize / fFormatInfo.BytesPerSec;
-      Result := DataSize;
-      Exit;
-    end;
-
-    // read packet data
-    while (fAudioPaketSize > 0) do
-    begin
-      DataSize := BufferSize;
-
-      {$IF LIBAVCODEC_VERSION >= 51030000} // 51.30.0
-      PaketDecodedSize := avcodec_decode_audio2(fCodecCtx, PSmallint(Buffer),
-                  DataSize, fAudioPaketData, fAudioPaketSize);
-      {$ELSE}
-      PaketDecodedSize := avcodec_decode_audio(fCodecCtx, PSmallint(Buffer),
-                  DataSize, fAudioPaketData, fAudioPaketSize);
-      {$IFEND}
-
-      if(PaketDecodedSize < 0) then
-      begin
-        // if error, skip frame
-        {$IFDEF DebugFFmpegDecode}
-        DebugWriteln('Skip audio frame');
-        {$ENDIF}
-        fAudioPaketSize := 0;
-        Break;
-      end;
-
-      Inc(PByte(fAudioPaketData), PaketDecodedSize);
-      Dec(fAudioPaketSize, PaketDecodedSize);
-
-      // check if avcodec_decode_audio returned data, otherwise fetch more frames
-      if (DataSize <= 0) then
-        Continue;
-
-      // update stream position by the amount of fetched data
-      fAudioStreamPos := fAudioStreamPos + DataSize / fFormatInfo.BytesPerSec;
-      
-      // we have data, return it and come back for more later
-      Result := DataSize;
-      Exit;
-    end;
-
-    // free old packet data
-    if (fAudioPaket.data <> nil) then
-      av_free_packet(@fAudioPaket);
-
-    // do not block queue on seeking (to avoid deadlocks on the DecoderLock)
-    if (IsSeeking()) then
-      BlockQueue := false
-    else
-      BlockQueue := true;
-
-    // request a new packet and block if none available.
-    // If this fails, the queue was aborted.
-    if (fPacketQueue.Get(fAudioPaket, BlockQueue) <= 0) then
-      Exit;
-
-    // handle Status-packet
-    if (PAnsiChar(fAudioPaket.data) = STATUS_PACKET) then
-    begin
-      fAudioPaket.data := nil;
-      fAudioPaketData := nil;
-      fAudioPaketSize := 0;
-
-      case (fAudioPaket.flags) of
-        PKT_STATUS_FLAG_FLUSH:
-        begin
-          // just used if SetPositionIntern was called without the flush flag.
-          FlushCodecBuffers;
-        end;
-        PKT_STATUS_FLAG_EOF: // end-of-file
-        begin
-          // ignore EOF while seeking
-          if (not IsSeeking()) then
-            SetEOF(true);
-          // buffer contains no data -> result = -1
-          Exit;
-        end;
-        PKT_STATUS_FLAG_ERROR:
-        begin
-          SetError(true);
-          Log.LogStatus('I/O Error', 'TFFmpegDecodeStream.DecodeFrame');
-          Exit;
-        end;
-        PKT_STATUS_FLAG_EMPTY:
-        begin
-          SilenceDuration := PDouble(fPacketQueue.GetStatusInfo(fAudioPaket))^;
-          fAudioPaketSilence := Round(SilenceDuration * fFormatInfo.SampleRate) * fFormatInfo.FrameSize;
-          fPacketQueue.FreeStatusInfo(fAudioPaket);
-        end
-        else
-        begin
-          Log.LogStatus('Unknown status', 'TFFmpegDecodeStream.DecodeFrame');
-        end;
-      end;
-
-      Continue;
-    end;
-
-    fAudioPaketData := fAudioPaket.data;
-    fAudioPaketSize := fAudioPaket.size;
-
-    // if available, update the stream position to the presentation time of this package
-    if(fAudioPaket.pts <> AV_NOPTS_VALUE) then
-    begin
-      {$IFDEF DebugFFmpegDecode}
-      TmpPos := fAudioStreamPos;
-      {$ENDIF}
-      fAudioStreamPos := av_q2d(fAudioStream^.time_base) * fAudioPaket.pts;
-      {$IFDEF DebugFFmpegDecode}
-      DebugWriteln('Timestamp: ' + floattostrf(fAudioStreamPos, ffFixed, 15, 3) + ' ' +
-                   '(Calc: ' + floattostrf(TmpPos, ffFixed, 15, 3) + '), ' +
-                   'Diff: ' + floattostrf(fAudioStreamPos-TmpPos, ffFixed, 15, 3));
-      {$ENDIF}
-    end;
-  end;
+  DecodeStream_setLoop(fStream, Enabled);
 end;
 
 function TFFmpegDecodeStream.ReadData(Buffer: PByteArray; BufferSize: integer): integer;
-var
-  CopyByteCount:   integer; // number of bytes to copy
-  RemainByteCount: integer; // number of bytes left (remain) to read
-  BufferPos: integer;
-
-  // prioritize pause requests
-  procedure LockDecoder();
-  begin
-    SDL_mutexP(fStateLock);
-    while (fDecoderPauseRequestCount > 0) do
-      SDL_CondWait(fDecoderResumeCond, fStateLock);
-    fDecoderLocked := true;
-    SDL_mutexV(fStateLock);
-  end;
-
-  procedure UnlockDecoder();
-  begin
-    SDL_mutexP(fStateLock);
-    fDecoderLocked := false;
-    SDL_CondBroadcast(fDecoderUnlockedCond);
-    SDL_mutexV(fStateLock);
-  end;
-
 begin
-  Result := -1;
-
-  // set number of bytes to copy to the output buffer
-  BufferPos := 0;
-
-  LockDecoder();
-  try
-    // leave if end-of-file is reached
-    if (EOF) then
-      Exit;
-
-    // copy data to output buffer
-    while (BufferPos < BufferSize) do
-    begin
-      // check if we need more data
-      if (fAudioBufferPos >= fAudioBufferSize) then
-      begin
-        fAudioBufferPos := 0;
-
-        // we have already sent all our data; get more
-        fAudioBufferSize := DecodeFrame(fAudioBuffer, AUDIO_BUFFER_SIZE);
-
-        // check for errors or EOF
-        if(fAudioBufferSize < 0) then
-        begin
-          Result := BufferPos;
-          Exit;
-        end;
-      end;
-
-      // calc number of new bytes in the decode-buffer
-      CopyByteCount := fAudioBufferSize - fAudioBufferPos;
-      // resize copy-count if more bytes available than needed (remaining bytes are used the next time)
-      RemainByteCount := BufferSize - BufferPos;
-      if (CopyByteCount > RemainByteCount) then
-        CopyByteCount := RemainByteCount;
-
-      Move(fAudioBuffer[fAudioBufferPos], Buffer[BufferPos], CopyByteCount);
-
-      Inc(BufferPos,      CopyByteCount);
-      Inc(fAudioBufferPos, CopyByteCount);
-    end;
-  finally
-    UnlockDecoder();
-  end;
-
-  Result := BufferSize;
+  Result := DecodeStream_readData(fStream, PCUint8(Buffer), BufferSize);
 end;
 
 
@@ -1109,26 +199,7 @@ end;
 
 function TAudioDecoder_FFmpeg.InitializeDecoder: boolean;
 begin
-  //Log.LogStatus('InitializeDecoder', 'UAudioDecoder_FFmpeg');
-  FFmpegCore := TMediaCore_FFmpeg.GetInstance();
-  av_register_all();
-
-  // Do not show uninformative error messages by default.
-  // FFmpeg prints all error-infos on the console by default what
-  // is very confusing as the playback of the files is correct.
-  // We consider these errors to be internal to FFMpeg. They can be fixed
-  // by the FFmpeg guys only and do not provide any useful information in
-  // respect to USDX.
-  {$IFNDEF EnableFFmpegErrorOutput}
-    {$IF LIBAVUTIL_VERSION_MAJOR >= 50}
-    av_log_set_level(AV_LOG_FATAL);
-    {$ELSE}
-    // FATAL and ERROR share one log-level, so we have to use QUIET
-    av_log_set_level(AV_LOG_QUIET);
-    {$IFEND}
-  {$ENDIF}
-
-  Result := true;
+  Result := Plugin_initialize(MediaPluginCore);
 end;
 
 function TAudioDecoder_FFmpeg.FinalizeDecoder(): boolean;
@@ -1152,7 +223,6 @@ begin
   Result := Stream;
 end;
 
-
 initialization
   MediaManager.Add(TAudioDecoder_FFmpeg.Create);
 
diff --git a/mediaplugin/src/media/UMediaPlugin.pas b/mediaplugin/src/media/UMediaPlugin.pas
new file mode 100644
index 00000000..097a28f2
--- /dev/null
+++ b/mediaplugin/src/media/UMediaPlugin.pas
@@ -0,0 +1,132 @@
+{* UltraStar Deluxe - Karaoke Game
+ *
+ * UltraStar Deluxe is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *}
+
+unit UMediaPlugin;
+
+interface
+
+{$IFDEF FPC}
+  {$MODE DELPHI }
+  {$PACKENUM 4}    (* use 4-byte enums *)
+  {$PACKRECORDS C} (* C/C++-compatible record packing *)
+{$ELSE}
+  {$MINENUMSIZE 4} (* use 4-byte enums *)
+{$ENDIF}
+
+uses
+  ctypes;
+
+type
+  PMediaPluginCore = ^TMediaPluginCore;
+  TMediaPluginCore = record
+	  log: procedure(level: cint; msg: PChar; context: PChar); cdecl;
+  end;
+
+  PDecodeStream = Pointer;
+
+  PCAudioFormatInfo = ^TCAudioFormatInfo;
+  TCAudioFormatInfo = record
+    sampleRate: double;
+    channels: cuint8;
+    format: cint;
+  end;
+
+const
+{$IFDEF MSWINDOWS}
+  ffmpegPlugin = 'ffmpeg_playback.dll';
+{$ENDIF}
+{$IFDEF LINUX}
+  ffmpegPlugin = 'ffmpeg_playback';
+{$ENDIF}
+{$IFDEF DARWIN}
+  ffmpegPlugin = 'ffmpeg_playback.dylib';
+  {$linklib ffmpegPlugin}
+{$ENDIF}
+
+function Plugin_initialize(core: PMediaPluginCore): cbool;
+  cdecl; external ffmpegPlugin;
+
+function DecodeStream_open(filename: PAnsiChar): PDecodeStream;
+  cdecl; external ffmpegPlugin;
+procedure DecodeStream_close(stream: PDecodeStream);
+  cdecl; external ffmpegPlugin;
+function DecodeStream_getLength(stream: PDecodeStream): double;
+  cdecl; external ffmpegPlugin;
+procedure DecodeStream_getAudioFormatInfo(stream: PDecodeStream; var info: TCAudioFormatInfo);
+  cdecl; external ffmpegPlugin;
+function DecodeStream_getPosition(stream: PDecodeStream): double;
+  cdecl; external ffmpegPlugin;
+procedure DecodeStream_setPosition(stream: PDecodeStream; time: double);
+  cdecl; external ffmpegPlugin;
+function DecodeStream_getLoop(stream: PDecodeStream): cbool;
+  cdecl; external ffmpegPlugin;
+procedure DecodeStream_setLoop(stream: PDecodeStream; enabled: cbool);
+  cdecl; external ffmpegPlugin;
+function DecodeStream_isEOF(stream: PDecodeStream): cbool;
+  cdecl; external ffmpegPlugin;
+function DecodeStream_isError(stream: PDecodeStream): cbool;
+  cdecl; external ffmpegPlugin;
+function DecodeStream_readData(stream: PDecodeStream; buffer: PCUint8; bufferSize: cint): cint;
+  cdecl; external ffmpegPlugin;
+
+function MediaPluginCore: PMediaPluginCore;
+
+implementation
+
+uses
+  ULog;
+
+var
+  MediaPluginCore_Instance: TMediaPluginCore;
+
+const
+  DebugLogLevels: array[0 .. 5] of integer = (
+    LOG_LEVEL_DEBUG,
+    LOG_LEVEL_INFO,
+    LOG_LEVEL_STATUS,
+    LOG_LEVEL_WARN,
+    LOG_LEVEL_ERROR,
+    LOG_LEVEL_CRITICAL
+  );
+
+procedure LogFunc(level: cint; msg: PChar; context: PChar); cdecl;
+begin
+  Log.LogMsg(msg, context, DebugLogLevels[level]);
+end;
+
+function MediaPluginCore: PMediaPluginCore;
+begin
+  Result := @MediaPluginCore_Instance;
+end;
+
+procedure InitializeMediaPluginCore;
+begin
+  MediaPluginCore.log := LogFunc;
+end;
+
+initialization
+  InitializeMediaPluginCore;
+
+end.