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|
/*
* Copyright (C) 2003-2014 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "MadDecoderPlugin.hxx"
#include "../DecoderAPI.hxx"
#include "input/InputStream.hxx"
#include "config/ConfigGlobal.hxx"
#include "tag/TagId3.hxx"
#include "tag/TagRva2.hxx"
#include "tag/TagHandler.hxx"
#include "tag/ReplayGain.hxx"
#include "CheckAudioFormat.hxx"
#include "util/StringUtil.hxx"
#include "util/ASCII.hxx"
#include "util/Error.hxx"
#include "util/Domain.hxx"
#include "Log.hxx"
#include <mad.h>
#ifdef HAVE_ID3TAG
#include <id3tag.h>
#endif
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static constexpr unsigned long FRAMES_CUSHION = 2000;
enum mp3_action {
DECODE_SKIP = -3,
DECODE_BREAK = -2,
DECODE_CONT = -1,
DECODE_OK = 0
};
enum muteframe {
MUTEFRAME_NONE,
MUTEFRAME_SKIP,
MUTEFRAME_SEEK
};
/* the number of samples of silence the decoder inserts at start */
static constexpr unsigned DECODERDELAY = 529;
static constexpr bool DEFAULT_GAPLESS_MP3_PLAYBACK = true;
static constexpr Domain mad_domain("mad");
static bool gapless_playback;
gcc_const
static SongTime
ToSongTime(mad_timer_t t)
{
return SongTime::FromMS(mad_timer_count(t, MAD_UNITS_MILLISECONDS));
}
static inline int32_t
mad_fixed_to_24_sample(mad_fixed_t sample)
{
static constexpr unsigned bits = 24;
static constexpr mad_fixed_t MIN = -MAD_F_ONE;
static constexpr mad_fixed_t MAX = MAD_F_ONE - 1;
/* round */
sample = sample + (1L << (MAD_F_FRACBITS - bits));
/* clip */
if (gcc_unlikely(sample > MAX))
sample = MAX;
else if (gcc_unlikely(sample < MIN))
sample = MIN;
/* quantize */
return sample >> (MAD_F_FRACBITS + 1 - bits);
}
static void
mad_fixed_to_24_buffer(int32_t *dest, const struct mad_synth *synth,
unsigned int start, unsigned int end,
unsigned int num_channels)
{
for (unsigned i = start; i < end; ++i)
for (unsigned c = 0; c < num_channels; ++c)
*dest++ = mad_fixed_to_24_sample(synth->pcm.samples[c][i]);
}
static bool
mp3_plugin_init(gcc_unused const config_param ¶m)
{
gapless_playback = config_get_bool(CONF_GAPLESS_MP3_PLAYBACK,
DEFAULT_GAPLESS_MP3_PLAYBACK);
return true;
}
struct MadDecoder {
static constexpr size_t READ_BUFFER_SIZE = 40960;
static constexpr size_t MP3_DATA_OUTPUT_BUFFER_SIZE = 2048;
struct mad_stream stream;
struct mad_frame frame;
struct mad_synth synth;
mad_timer_t timer;
unsigned char input_buffer[READ_BUFFER_SIZE];
int32_t output_buffer[MP3_DATA_OUTPUT_BUFFER_SIZE];
SignedSongTime total_time;
SongTime elapsed_time;
SongTime seek_time;
enum muteframe mute_frame;
long *frame_offsets;
mad_timer_t *times;
unsigned long highest_frame;
unsigned long max_frames;
unsigned long current_frame;
unsigned int drop_start_frames;
unsigned int drop_end_frames;
unsigned int drop_start_samples;
unsigned int drop_end_samples;
bool found_replay_gain;
bool found_first_frame;
bool decoded_first_frame;
unsigned long bit_rate;
Decoder *const decoder;
InputStream &input_stream;
enum mad_layer layer;
MadDecoder(Decoder *decoder, InputStream &input_stream);
~MadDecoder();
bool Seek(long offset);
bool FillBuffer();
void ParseId3(size_t tagsize, Tag **mpd_tag);
enum mp3_action DecodeNextFrameHeader(Tag **tag);
enum mp3_action DecodeNextFrame();
gcc_pure
offset_type ThisFrameOffset() const;
gcc_pure
offset_type RestIncludingThisFrame() const;
/**
* Attempt to calulcate the length of the song from filesize
*/
void FileSizeToSongLength();
bool DecodeFirstFrame(Tag **tag);
gcc_pure
long TimeToFrame(SongTime t) const;
void UpdateTimerNextFrame();
/**
* Sends the synthesized current frame via decoder_data().
*/
DecoderCommand SendPCM(unsigned i, unsigned pcm_length);
/**
* Synthesize the current frame and send it via
* decoder_data().
*/
DecoderCommand SyncAndSend();
bool Read();
};
MadDecoder::MadDecoder(Decoder *_decoder,
InputStream &_input_stream)
:mute_frame(MUTEFRAME_NONE),
frame_offsets(nullptr),
times(nullptr),
highest_frame(0), max_frames(0), current_frame(0),
drop_start_frames(0), drop_end_frames(0),
drop_start_samples(0), drop_end_samples(0),
found_replay_gain(false),
found_first_frame(false), decoded_first_frame(false),
decoder(_decoder), input_stream(_input_stream),
layer(mad_layer(0))
{
mad_stream_init(&stream);
mad_stream_options(&stream, MAD_OPTION_IGNORECRC);
mad_frame_init(&frame);
mad_synth_init(&synth);
mad_timer_reset(&timer);
}
inline bool
MadDecoder::Seek(long offset)
{
Error error;
if (!input_stream.LockSeek(offset, error))
return false;
mad_stream_buffer(&stream, input_buffer, 0);
stream.error = MAD_ERROR_NONE;
return true;
}
inline bool
MadDecoder::FillBuffer()
{
size_t remaining, length;
unsigned char *dest;
if (stream.next_frame != nullptr) {
remaining = stream.bufend - stream.next_frame;
memmove(input_buffer, stream.next_frame, remaining);
dest = input_buffer + remaining;
length = READ_BUFFER_SIZE - remaining;
} else {
remaining = 0;
length = READ_BUFFER_SIZE;
dest = input_buffer;
}
/* we've exhausted the read buffer, so give up!, these potential
* mp3 frames are way too big, and thus unlikely to be mp3 frames */
if (length == 0)
return false;
length = decoder_read(decoder, input_stream, dest, length);
if (length == 0)
return false;
mad_stream_buffer(&stream, input_buffer, length + remaining);
stream.error = MAD_ERROR_NONE;
return true;
}
#ifdef HAVE_ID3TAG
static bool
parse_id3_replay_gain_info(ReplayGainInfo &rgi,
struct id3_tag *tag)
{
bool found = false;
rgi.Clear();
struct id3_frame *frame;
for (unsigned i = 0; (frame = id3_tag_findframe(tag, "TXXX", i)); i++) {
if (frame->nfields < 3)
continue;
char *const key = (char *)
id3_ucs4_latin1duplicate(id3_field_getstring
(&frame->fields[1]));
char *const value = (char *)
id3_ucs4_latin1duplicate(id3_field_getstring
(&frame->fields[2]));
if (ParseReplayGainTag(rgi, key, value))
found = true;
free(key);
free(value);
}
return found ||
/* fall back on RVA2 if no replaygain tags found */
tag_rva2_parse(tag, rgi);
}
#endif
#ifdef HAVE_ID3TAG
gcc_pure
static MixRampInfo
parse_id3_mixramp(struct id3_tag *tag)
{
MixRampInfo result;
struct id3_frame *frame;
for (unsigned i = 0; (frame = id3_tag_findframe(tag, "TXXX", i)); i++) {
if (frame->nfields < 3)
continue;
char *const key = (char *)
id3_ucs4_latin1duplicate(id3_field_getstring
(&frame->fields[1]));
char *const value = (char *)
id3_ucs4_latin1duplicate(id3_field_getstring
(&frame->fields[2]));
if (StringEqualsCaseASCII(key, "mixramp_start")) {
result.SetStart(value);
} else if (StringEqualsCaseASCII(key, "mixramp_end")) {
result.SetEnd(value);
}
free(key);
free(value);
}
return result;
}
#endif
inline void
MadDecoder::ParseId3(size_t tagsize, Tag **mpd_tag)
{
#ifdef HAVE_ID3TAG
id3_byte_t *allocated = nullptr;
const id3_length_t count = stream.bufend - stream.this_frame;
const id3_byte_t *id3_data;
if (tagsize <= count) {
id3_data = stream.this_frame;
mad_stream_skip(&(stream), tagsize);
} else {
allocated = new id3_byte_t[tagsize];
memcpy(allocated, stream.this_frame, count);
mad_stream_skip(&(stream), count);
if (!decoder_read_full(decoder, input_stream,
allocated + count, tagsize - count)) {
LogDebug(mad_domain, "error parsing ID3 tag");
delete[] allocated;
return;
}
id3_data = allocated;
}
struct id3_tag *const id3_tag = id3_tag_parse(id3_data, tagsize);
if (id3_tag == nullptr) {
delete[] allocated;
return;
}
if (mpd_tag) {
Tag *tmp_tag = tag_id3_import(id3_tag);
if (tmp_tag != nullptr) {
delete *mpd_tag;
*mpd_tag = tmp_tag;
}
}
if (decoder != nullptr) {
ReplayGainInfo rgi;
if (parse_id3_replay_gain_info(rgi, id3_tag)) {
decoder_replay_gain(*decoder, &rgi);
found_replay_gain = true;
}
decoder_mixramp(*decoder, parse_id3_mixramp(id3_tag));
}
id3_tag_delete(id3_tag);
delete[] allocated;
#else /* !HAVE_ID3TAG */
(void)mpd_tag;
/* This code is enabled when libid3tag is disabled. Instead
of parsing the ID3 frame, it just skips it. */
size_t count = stream.bufend - stream.this_frame;
if (tagsize <= count) {
mad_stream_skip(&stream, tagsize);
} else {
mad_stream_skip(&stream, count);
decoder_skip(decoder, input_stream, tagsize - count);
}
#endif
}
#ifndef HAVE_ID3TAG
/**
* This function emulates libid3tag when it is disabled. Instead of
* doing a real analyzation of the frame, it just checks whether the
* frame begins with the string "ID3". If so, it returns the length
* of the ID3 frame.
*/
static signed long
id3_tag_query(const void *p0, size_t length)
{
const char *p = (const char *)p0;
return length >= 10 && memcmp(p, "ID3", 3) == 0
? (p[8] << 7) + p[9] + 10
: 0;
}
#endif /* !HAVE_ID3TAG */
static enum mp3_action
RecoverFrameError(struct mad_stream &stream)
{
if (MAD_RECOVERABLE(stream.error))
return DECODE_SKIP;
else if (stream.error == MAD_ERROR_BUFLEN)
return DECODE_CONT;
FormatWarning(mad_domain,
"unrecoverable frame level error: %s",
mad_stream_errorstr(&stream));
return DECODE_BREAK;
}
enum mp3_action
MadDecoder::DecodeNextFrameHeader(Tag **tag)
{
if ((stream.buffer == nullptr || stream.error == MAD_ERROR_BUFLEN) &&
!FillBuffer())
return DECODE_BREAK;
if (mad_header_decode(&frame.header, &stream)) {
if (stream.error == MAD_ERROR_LOSTSYNC && stream.this_frame) {
signed long tagsize = id3_tag_query(stream.this_frame,
stream.bufend -
stream.this_frame);
if (tagsize > 0) {
if (tag && !(*tag)) {
ParseId3((size_t)tagsize, tag);
} else {
mad_stream_skip(&stream, tagsize);
}
return DECODE_CONT;
}
}
return RecoverFrameError(stream);
}
enum mad_layer new_layer = frame.header.layer;
if (layer == (mad_layer)0) {
if (new_layer != MAD_LAYER_II && new_layer != MAD_LAYER_III) {
/* Only layer 2 and 3 have been tested to work */
return DECODE_SKIP;
}
layer = new_layer;
} else if (new_layer != layer) {
/* Don't decode frames with a different layer than the first */
return DECODE_SKIP;
}
return DECODE_OK;
}
enum mp3_action
MadDecoder::DecodeNextFrame()
{
if ((stream.buffer == nullptr || stream.error == MAD_ERROR_BUFLEN) &&
!FillBuffer())
return DECODE_BREAK;
if (mad_frame_decode(&frame, &stream)) {
if (stream.error == MAD_ERROR_LOSTSYNC) {
signed long tagsize = id3_tag_query(stream.this_frame,
stream.bufend -
stream.this_frame);
if (tagsize > 0) {
mad_stream_skip(&stream, tagsize);
return DECODE_CONT;
}
}
return RecoverFrameError(stream);
}
return DECODE_OK;
}
/* xing stuff stolen from alsaplayer, and heavily modified by jat */
static constexpr unsigned XI_MAGIC = (('X' << 8) | 'i');
static constexpr unsigned NG_MAGIC = (('n' << 8) | 'g');
static constexpr unsigned IN_MAGIC = (('I' << 8) | 'n');
static constexpr unsigned FO_MAGIC = (('f' << 8) | 'o');
enum xing_magic {
XING_MAGIC_XING, /* VBR */
XING_MAGIC_INFO /* CBR */
};
struct xing {
long flags; /* valid fields (see below) */
unsigned long frames; /* total number of frames */
unsigned long bytes; /* total number of bytes */
unsigned char toc[100]; /* 100-point seek table */
long scale; /* VBR quality */
enum xing_magic magic; /* header magic */
};
static const unsigned XING_FRAMES = 1;
static const unsigned XING_BYTES = 2;
static const unsigned XING_TOC = 4;
static const unsigned XING_SCALE = 8;
struct lame_version {
unsigned major;
unsigned minor;
};
struct lame {
char encoder[10]; /* 9 byte encoder name/version ("LAME3.97b") */
struct lame_version version; /* struct containing just the version */
float peak; /* replaygain peak */
float track_gain; /* replaygain track gain */
float album_gain; /* replaygain album gain */
int encoder_delay; /* # of added samples at start of mp3 */
int encoder_padding; /* # of added samples at end of mp3 */
int crc; /* CRC of the first 190 bytes of this frame */
};
static bool
parse_xing(struct xing *xing, struct mad_bitptr *ptr, int *oldbitlen)
{
int bitlen = *oldbitlen;
if (bitlen < 16)
return false;
const unsigned long bits = mad_bit_read(ptr, 16);
bitlen -= 16;
if (bits == XI_MAGIC) {
if (bitlen < 16)
return false;
if (mad_bit_read(ptr, 16) != NG_MAGIC)
return false;
bitlen -= 16;
xing->magic = XING_MAGIC_XING;
} else if (bits == IN_MAGIC) {
if (bitlen < 16)
return false;
if (mad_bit_read(ptr, 16) != FO_MAGIC)
return false;
bitlen -= 16;
xing->magic = XING_MAGIC_INFO;
}
else if (bits == NG_MAGIC) xing->magic = XING_MAGIC_XING;
else if (bits == FO_MAGIC) xing->magic = XING_MAGIC_INFO;
else
return false;
if (bitlen < 32)
return false;
xing->flags = mad_bit_read(ptr, 32);
bitlen -= 32;
if (xing->flags & XING_FRAMES) {
if (bitlen < 32)
return false;
xing->frames = mad_bit_read(ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_BYTES) {
if (bitlen < 32)
return false;
xing->bytes = mad_bit_read(ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_TOC) {
if (bitlen < 800)
return false;
for (unsigned i = 0; i < 100; ++i)
xing->toc[i] = mad_bit_read(ptr, 8);
bitlen -= 800;
}
if (xing->flags & XING_SCALE) {
if (bitlen < 32)
return false;
xing->scale = mad_bit_read(ptr, 32);
bitlen -= 32;
}
/* Make sure we consume no less than 120 bytes (960 bits) in hopes that
* the LAME tag is found there, and not right after the Xing header */
const int bitsleft = 960 - (*oldbitlen - bitlen);
if (bitsleft < 0)
return false;
else if (bitsleft > 0) {
mad_bit_read(ptr, bitsleft);
bitlen -= bitsleft;
}
*oldbitlen = bitlen;
return true;
}
static bool
parse_lame(struct lame *lame, struct mad_bitptr *ptr, int *bitlen)
{
/* Unlike the xing header, the lame tag has a fixed length. Fail if
* not all 36 bytes (288 bits) are there. */
if (*bitlen < 288)
return false;
for (unsigned i = 0; i < 9; i++)
lame->encoder[i] = (char)mad_bit_read(ptr, 8);
lame->encoder[9] = '\0';
*bitlen -= 72;
/* This is technically incorrect, since the encoder might not be lame.
* But there's no other way to determine if this is a lame tag, and we
* wouldn't want to go reading a tag that's not there. */
if (!StringStartsWith(lame->encoder, "LAME"))
return false;
if (sscanf(lame->encoder+4, "%u.%u",
&lame->version.major, &lame->version.minor) != 2)
return false;
FormatDebug(mad_domain, "detected LAME version %i.%i (\"%s\")",
lame->version.major, lame->version.minor, lame->encoder);
/* The reference volume was changed from the 83dB used in the
* ReplayGain spec to 89dB in lame 3.95.1. Bump the gain for older
* versions, since everyone else uses 89dB instead of 83dB.
* Unfortunately, lame didn't differentiate between 3.95 and 3.95.1, so
* it's impossible to make the proper adjustment for 3.95.
* Fortunately, 3.95 was only out for about a day before 3.95.1 was
* released. -- tmz */
int adj = 0;
if (lame->version.major < 3 ||
(lame->version.major == 3 && lame->version.minor < 95))
adj = 6;
mad_bit_read(ptr, 16);
lame->peak = mad_f_todouble(mad_bit_read(ptr, 32) << 5); /* peak */
FormatDebug(mad_domain, "LAME peak found: %f", lame->peak);
lame->track_gain = 0;
unsigned name = mad_bit_read(ptr, 3); /* gain name */
unsigned orig = mad_bit_read(ptr, 3); /* gain originator */
unsigned sign = mad_bit_read(ptr, 1); /* sign bit */
unsigned gain = mad_bit_read(ptr, 9); /* gain*10 */
if (gain && name == 1 && orig != 0) {
lame->track_gain = ((sign ? -gain : gain) / 10.0) + adj;
FormatDebug(mad_domain, "LAME track gain found: %f",
lame->track_gain);
}
/* tmz reports that this isn't currently written by any version of lame
* (as of 3.97). Since we have no way of testing it, don't use it.
* Wouldn't want to go blowing someone's ears just because we read it
* wrong. :P -- jat */
lame->album_gain = 0;
#if 0
name = mad_bit_read(ptr, 3); /* gain name */
orig = mad_bit_read(ptr, 3); /* gain originator */
sign = mad_bit_read(ptr, 1); /* sign bit */
gain = mad_bit_read(ptr, 9); /* gain*10 */
if (gain && name == 2 && orig != 0) {
lame->album_gain = ((sign ? -gain : gain) / 10.0) + adj;
FormatDebug(mad_domain, "LAME album gain found: %f",
lame->track_gain);
}
#else
mad_bit_read(ptr, 16);
#endif
mad_bit_read(ptr, 16);
lame->encoder_delay = mad_bit_read(ptr, 12);
lame->encoder_padding = mad_bit_read(ptr, 12);
FormatDebug(mad_domain, "encoder delay is %i, encoder padding is %i",
lame->encoder_delay, lame->encoder_padding);
mad_bit_read(ptr, 80);
lame->crc = mad_bit_read(ptr, 16);
*bitlen -= 216;
return true;
}
static inline SongTime
mp3_frame_duration(const struct mad_frame *frame)
{
return ToSongTime(frame->header.duration);
}
inline offset_type
MadDecoder::ThisFrameOffset() const
{
auto offset = input_stream.GetOffset();
if (stream.this_frame != nullptr)
offset -= stream.bufend - stream.this_frame;
else
offset -= stream.bufend - stream.buffer;
return offset;
}
inline offset_type
MadDecoder::RestIncludingThisFrame() const
{
return input_stream.GetSize() - ThisFrameOffset();
}
inline void
MadDecoder::FileSizeToSongLength()
{
if (input_stream.KnownSize()) {
offset_type rest = RestIncludingThisFrame();
const SongTime frame_duration = mp3_frame_duration(&frame);
const SongTime duration =
SongTime::FromScale<uint64_t>(rest,
frame.header.bitrate / 8);
total_time = duration;
max_frames = (frame_duration.IsPositive()
? duration.count() / frame_duration.count()
: 0)
+ FRAMES_CUSHION;
} else {
max_frames = FRAMES_CUSHION;
total_time = SignedSongTime::Negative();
}
}
inline bool
MadDecoder::DecodeFirstFrame(Tag **tag)
{
struct xing xing;
xing.frames = 0;
while (true) {
enum mp3_action ret;
do {
ret = DecodeNextFrameHeader(tag);
} while (ret == DECODE_CONT);
if (ret == DECODE_BREAK)
return false;
if (ret == DECODE_SKIP) continue;
do {
ret = DecodeNextFrame();
} while (ret == DECODE_CONT);
if (ret == DECODE_BREAK)
return false;
if (ret == DECODE_OK) break;
}
struct mad_bitptr ptr = stream.anc_ptr;
int bitlen = stream.anc_bitlen;
FileSizeToSongLength();
/*
* if an xing tag exists, use that!
*/
if (parse_xing(&xing, &ptr, &bitlen)) {
mute_frame = MUTEFRAME_SKIP;
if ((xing.flags & XING_FRAMES) && xing.frames) {
mad_timer_t duration = frame.header.duration;
mad_timer_multiply(&duration, xing.frames);
total_time = ToSongTime(duration);
max_frames = xing.frames;
}
struct lame lame;
if (parse_lame(&lame, &ptr, &bitlen)) {
if (gapless_playback && input_stream.IsSeekable()) {
drop_start_samples = lame.encoder_delay +
DECODERDELAY;
drop_end_samples = lame.encoder_padding;
}
/* Album gain isn't currently used. See comment in
* parse_lame() for details. -- jat */
if (decoder != nullptr && !found_replay_gain &&
lame.track_gain) {
ReplayGainInfo rgi;
rgi.Clear();
rgi.tuples[REPLAY_GAIN_TRACK].gain = lame.track_gain;
rgi.tuples[REPLAY_GAIN_TRACK].peak = lame.peak;
decoder_replay_gain(*decoder, &rgi);
}
}
}
if (!max_frames)
return false;
if (max_frames > 8 * 1024 * 1024) {
FormatWarning(mad_domain,
"mp3 file header indicates too many frames: %lu",
max_frames);
return false;
}
frame_offsets = new long[max_frames];
times = new mad_timer_t[max_frames];
return true;
}
MadDecoder::~MadDecoder()
{
mad_synth_finish(&synth);
mad_frame_finish(&frame);
mad_stream_finish(&stream);
delete[] frame_offsets;
delete[] times;
}
/* this is primarily used for getting total time for tags */
static std::pair<bool, SignedSongTime>
mad_decoder_total_file_time(InputStream &is)
{
MadDecoder data(nullptr, is);
return data.DecodeFirstFrame(nullptr)
? std::make_pair(true, data.total_time)
: std::make_pair(false, SignedSongTime::Negative());
}
long
MadDecoder::TimeToFrame(SongTime t) const
{
unsigned long i;
for (i = 0; i < highest_frame; ++i) {
auto frame_time = ToSongTime(times[i]);
if (frame_time >= t)
break;
}
return i;
}
void
MadDecoder::UpdateTimerNextFrame()
{
if (current_frame >= highest_frame) {
/* record this frame's properties in frame_offsets
(for seeking) and times */
bit_rate = frame.header.bitrate;
if (current_frame >= max_frames)
/* cap current_frame */
current_frame = max_frames - 1;
else
highest_frame++;
frame_offsets[current_frame] = ThisFrameOffset();
mad_timer_add(&timer, frame.header.duration);
times[current_frame] = timer;
} else
/* get the new timer value from "times" */
timer = times[current_frame];
current_frame++;
elapsed_time = ToSongTime(timer);
}
DecoderCommand
MadDecoder::SendPCM(unsigned i, unsigned pcm_length)
{
unsigned max_samples = sizeof(output_buffer) /
sizeof(output_buffer[0]) /
MAD_NCHANNELS(&frame.header);
while (i < pcm_length) {
unsigned int num_samples = pcm_length - i;
if (num_samples > max_samples)
num_samples = max_samples;
i += num_samples;
mad_fixed_to_24_buffer(output_buffer, &synth,
i - num_samples, i,
MAD_NCHANNELS(&frame.header));
num_samples *= MAD_NCHANNELS(&frame.header);
auto cmd = decoder_data(*decoder, input_stream, output_buffer,
sizeof(output_buffer[0]) * num_samples,
bit_rate / 1000);
if (cmd != DecoderCommand::NONE)
return cmd;
}
return DecoderCommand::NONE;
}
inline DecoderCommand
MadDecoder::SyncAndSend()
{
mad_synth_frame(&synth, &frame);
if (!found_first_frame) {
unsigned int samples_per_frame = synth.pcm.length;
drop_start_frames = drop_start_samples / samples_per_frame;
drop_end_frames = drop_end_samples / samples_per_frame;
drop_start_samples = drop_start_samples % samples_per_frame;
drop_end_samples = drop_end_samples % samples_per_frame;
found_first_frame = true;
}
if (drop_start_frames > 0) {
drop_start_frames--;
return DecoderCommand::NONE;
} else if ((drop_end_frames > 0) &&
(current_frame == (max_frames + 1 - drop_end_frames))) {
/* stop decoding, effectively dropping all remaining
frames */
return DecoderCommand::STOP;
}
unsigned i = 0;
if (!decoded_first_frame) {
i = drop_start_samples;
decoded_first_frame = true;
}
unsigned pcm_length = synth.pcm.length;
if (drop_end_samples &&
(current_frame == max_frames - drop_end_frames)) {
if (drop_end_samples >= pcm_length)
pcm_length = 0;
else
pcm_length -= drop_end_samples;
}
auto cmd = SendPCM(i, pcm_length);
if (cmd != DecoderCommand::NONE)
return cmd;
if (drop_end_samples &&
(current_frame == max_frames - drop_end_frames))
/* stop decoding, effectively dropping
* all remaining samples */
return DecoderCommand::STOP;
return DecoderCommand::NONE;
}
inline bool
MadDecoder::Read()
{
UpdateTimerNextFrame();
switch (mute_frame) {
DecoderCommand cmd;
case MUTEFRAME_SKIP:
mute_frame = MUTEFRAME_NONE;
break;
case MUTEFRAME_SEEK:
if (elapsed_time >= seek_time)
mute_frame = MUTEFRAME_NONE;
break;
case MUTEFRAME_NONE:
cmd = SyncAndSend();
if (cmd == DecoderCommand::SEEK) {
assert(input_stream.IsSeekable());
unsigned long j =
TimeToFrame(decoder_seek_time(*decoder));
if (j < highest_frame) {
if (Seek(frame_offsets[j])) {
current_frame = j;
decoder_command_finished(*decoder);
} else
decoder_seek_error(*decoder);
} else {
seek_time = decoder_seek_time(*decoder);
mute_frame = MUTEFRAME_SEEK;
decoder_command_finished(*decoder);
}
} else if (cmd != DecoderCommand::NONE)
return false;
}
while (true) {
enum mp3_action ret;
do {
Tag *tag = nullptr;
ret = DecodeNextFrameHeader(&tag);
if (tag != nullptr) {
decoder_tag(*decoder, input_stream,
std::move(*tag));
delete tag;
}
} while (ret == DECODE_CONT);
if (ret == DECODE_BREAK)
return false;
const bool skip = ret == DECODE_SKIP;
if (mute_frame == MUTEFRAME_NONE) {
do {
ret = DecodeNextFrame();
} while (ret == DECODE_CONT);
if (ret == DECODE_BREAK)
return false;
}
if (!skip && ret == DECODE_OK)
return true;
}
}
static void
mp3_decode(Decoder &decoder, InputStream &input_stream)
{
MadDecoder data(&decoder, input_stream);
Tag *tag = nullptr;
if (!data.DecodeFirstFrame(&tag)) {
delete tag;
if (decoder_get_command(decoder) == DecoderCommand::NONE)
LogError(mad_domain,
"input/Input does not appear to be a mp3 bit stream");
return;
}
Error error;
AudioFormat audio_format;
if (!audio_format_init_checked(audio_format,
data.frame.header.samplerate,
SampleFormat::S24_P32,
MAD_NCHANNELS(&data.frame.header),
error)) {
LogError(error);
delete tag;
return;
}
decoder_initialized(decoder, audio_format,
input_stream.IsSeekable(),
data.total_time);
if (tag != nullptr) {
decoder_tag(decoder, input_stream, std::move(*tag));
delete tag;
}
while (data.Read()) {}
}
static bool
mad_decoder_scan_stream(InputStream &is,
const struct tag_handler *handler, void *handler_ctx)
{
const auto result = mad_decoder_total_file_time(is);
if (!result.first)
return false;
if (!result.second.IsNegative())
tag_handler_invoke_duration(handler, handler_ctx,
SongTime(result.second));
return true;
}
static const char *const mp3_suffixes[] = { "mp3", "mp2", nullptr };
static const char *const mp3_mime_types[] = { "audio/mpeg", nullptr };
const struct DecoderPlugin mad_decoder_plugin = {
"mad",
mp3_plugin_init,
nullptr,
mp3_decode,
nullptr,
nullptr,
mad_decoder_scan_stream,
nullptr,
mp3_suffixes,
mp3_mime_types,
};
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