/* Attempts to read an ID3 tag at the current location in stream and
* consume it all. Returns -1 if no tag is found. Its up to caller
* to recover. */
static int mp3_inputtag(snd_stream_t *stream)
{
mp3_priv_t *p = (mp3_priv_t *) stream->priv;
int rc = -1;
size_t remaining;
size_t tagsize;
/* FIXME: This needs some more work if we are to ever
* look at the ID3 frame. This is because the Stream
* may not be able to hold the complete ID3 frame.
* We should consume the whole frame inside tagtype()
* instead of outside of tagframe(). That would support
* recovering when Stream contains less then 8-bytes (header)
* and also when ID3v2 is bigger then Stream buffer size.
* Need to pass in stream so that buffer can be
* consumed as well as letting additional data to be
* read in.
*/
remaining = p->Stream.bufend - p->Stream.next_frame;
tagsize = mp3_tagsize(p->Stream.this_frame, remaining);
if (tagsize != 0)
{
mad_stream_skip(&p->Stream, tagsize);
rc = 0;
}
/* We know that a valid frame hasn't been found yet
* so help libmad out and go back into frame seek mode.
* This is true whether an ID3 tag was found or not.
*/
mad_stream_sync(&p->Stream);
return rc;
}
static enum mad_flow handle_error(void *data, struct mad_stream *stream, struct mad_frame *frame)
{
signed long tagsize;
switch(stream->error)
{
case MAD_ERROR_BADDATAPTR:
return MAD_FLOW_CONTINUE;
case MAD_ERROR_LOSTSYNC:
tagsize = id3_tag_query(stream->this_frame,stream->bufend - stream->this_frame);
if(tagsize > 0)
{
mad_stream_skip(stream, tagsize);
return MAD_FLOW_CONTINUE;
}
default:
break;
}
if(stream->error == MAD_ERROR_BADCRC)
{
mad_frame_mute(frame);
return MAD_FLOW_IGNORE;
}
return MAD_FLOW_CONTINUE;
}
// Attempts to read an ID3 tag at the current location in stream and
// consume it all. Returns SOX_EOF if no tag is found. Its up to
// caller to recover.
// Returns true if a tag was found and consumed.
//
bool MadDecoder::consumeId3Tag()
{
// FIXME: This needs some more work if we are to ever
// look at the ID3 frame. This is because the Stream
// may not be able to hold the complete ID3 frame.
// We should consume the whole frame inside getId3TagSize()
// instead of outside of tagframe(). That would support
// recovering when Stream contains less then 8-bytes (header)
// and also when ID3v2 is bigger then Stream buffer size.
// Need to pass in stream so that buffer can be
// consumed as well as letting additional data to be
// read in.
//
bool result = false;
size_t leftover = madStream_.bufend - madStream_.next_frame;
size_t tagsize = getId3TagSize(madStream_.this_frame, leftover);
if (tagsize > 0)
{
mad_stream_skip(&madStream_, tagsize);
result = true;
}
/* We know that a valid frame hasn't been found yet
* so help libmad out and go back into frame seek mode.
* This is true whether an ID3 tag was found or not.
*/
mad_stream_sync(&madStream_);
return result;
}
int TrackDuration::duration(const QFileInfo &fileinfo)
{
QString fn = fileinfo.absoluteFilePath();
if (fn.isEmpty())
return 0;
QFile file(fn);
if (!file.open(QFile::ReadOnly))
return 0;
mad_stream infostream;
mad_header infoheader;
mad_timer_t infotimer;
mad_stream_init(&infostream);
mad_header_init(&infoheader);
mad_timer_reset(&infotimer);
qint64 r;
qint64 l = 0;
unsigned char* buf = new unsigned char[INPUT_BUFFER_SIZE];
while (!file.atEnd()) {
if (l < INPUT_BUFFER_SIZE) {
r = file.read(reinterpret_cast<char*>(buf) + l, INPUT_BUFFER_SIZE - l);
l += r;
}
mad_stream_buffer(&infostream, buf, l);
for (;;) {
if (mad_header_decode(&infoheader, &infostream)) {
if (!MAD_RECOVERABLE(infostream.error))
break;
if (infostream.error == MAD_ERROR_LOSTSYNC) {
TagLib::ID3v2::Header header;
uint size = (uint)(infostream.bufend - infostream.this_frame);
if (size >= header.size()) {
header.setData(TagLib::ByteVector(reinterpret_cast<const char*>(infostream.this_frame), size));
uint tagsize = header.tagSize();
if (tagsize > 0) {
mad_stream_skip(&infostream, qMin(tagsize, size));
continue;
}
}
}
qDebug() << "header decode error while getting file info" << infostream.error;
continue;
}
mad_timer_add(&infotimer, infoheader.duration);
}
if (infostream.error != MAD_ERROR_BUFLEN && infostream.error != MAD_ERROR_BUFPTR)
break;
memmove(buf, infostream.next_frame, &(buf[l]) - infostream.next_frame);
l -= (infostream.next_frame - buf);
}
mad_stream_finish(&infostream);
mad_header_finish(&infoheader);
delete[] buf;
return timerToMs(&infotimer);
}
static enum mp3_action
decode_next_frame_header(struct mp3_data *data, G_GNUC_UNUSED struct tag **tag)
{
enum mad_layer layer;
if ((data->stream).buffer == NULL
|| (data->stream).error == MAD_ERROR_BUFLEN) {
if (!mp3_fill_buffer(data))
return DECODE_BREAK;
}
if (mad_header_decode(&data->frame.header, &data->stream)) {
if ((data->stream).error == MAD_ERROR_LOSTSYNC &&
(data->stream).this_frame) {
signed long tagsize = id3_tag_query((data->stream).
this_frame,
(data->stream).
bufend -
(data->stream).
this_frame);
if (tagsize > 0) {
if (tag && !(*tag)) {
mp3_parse_id3(data, (size_t)tagsize,
tag);
} else {
mad_stream_skip(&(data->stream),
tagsize);
}
return DECODE_CONT;
}
}
if (MAD_RECOVERABLE((data->stream).error)) {
return DECODE_SKIP;
} else {
if ((data->stream).error == MAD_ERROR_BUFLEN)
return DECODE_CONT;
else {
g_warning("unrecoverable frame level error "
"(%s).\n",
mad_stream_errorstr(&data->stream));
return DECODE_BREAK;
}
}
}
layer = data->frame.header.layer;
if (!data->layer) {
if (layer != MAD_LAYER_II && layer != MAD_LAYER_III) {
/* Only layer 2 and 3 have been tested to work */
return DECODE_SKIP;
}
data->layer = layer;
} else if (layer != data->layer) {
/* Don't decode frames with a different layer than the first */
return DECODE_SKIP;
}
return DECODE_OK;
}
int LibMadWrapper::findValidHeader(struct mad_header &header)
{
int ret;
while ((ret = mad_header_decode(&header, this->stream)) != 0 && MAD_RECOVERABLE(this->stream->error))
{
if (this->stream->error == MAD_ERROR_LOSTSYNC)
{
long tagsize = id3_tag_query(this->stream->this_frame, this->stream->bufend - this->stream->this_frame);
if (tagsize > 0)
{
mad_stream_skip(this->stream, tagsize);
continue;
}
}
}
return ret;
}
static enum mp3_action
decodeNextFrame(struct mp3_data *data)
{
if ((data->stream).buffer == NULL
|| (data->stream).error == MAD_ERROR_BUFLEN) {
if (!mp3_fill_buffer(data))
return DECODE_BREAK;
}
if (mad_frame_decode(&data->frame, &data->stream)) {
#ifdef HAVE_ID3TAG
if ((data->stream).error == MAD_ERROR_LOSTSYNC) {
signed long tagsize = id3_tag_query((data->stream).
this_frame,
(data->stream).
bufend -
(data->stream).
this_frame);
if (tagsize > 0) {
mad_stream_skip(&(data->stream), tagsize);
return DECODE_CONT;
}
}
#endif
if (MAD_RECOVERABLE((data->stream).error)) {
return DECODE_SKIP;
} else {
if ((data->stream).error == MAD_ERROR_BUFLEN)
return DECODE_CONT;
else {
g_warning("unrecoverable frame level error "
"(%s).\n",
mad_stream_errorstr(&data->stream));
return DECODE_BREAK;
}
}
}
return DECODE_OK;
}
/**
* MP3音乐播放回调函数，
* 负责将解码数据填充声音缓存区
*
* @note 声音缓存区的格式为双声道，16位低字序
*
* @param buf 声音缓冲区指针
* @param reqn 缓冲区帧大小
* @param pdata 用户数据，无用
*/
static int mp3_audiocallback(void *buf, unsigned int reqn, void *pdata)
{
int avail_frame;
int snd_buf_frame_size = (int) reqn;
int ret;
double incr;
signed short *audio_buf = buf;
unsigned i;
uint16_t *output;
UNUSED(pdata);
if (g_status != ST_PLAYING) {
if (handle_seek() == -1) {
__end();
return -1;
}
xAudioClearSndBuf(buf, snd_buf_frame_size);
xrKernelDelayThread(100000);
return 0;
}
while (snd_buf_frame_size > 0) {
avail_frame = g_buff_frame_size - g_buff_frame_start;
if (avail_frame >= snd_buf_frame_size) {
send_to_sndbuf(audio_buf,
&g_buff[g_buff_frame_start * 2],
snd_buf_frame_size, 2);
g_buff_frame_start += snd_buf_frame_size;
audio_buf += snd_buf_frame_size * 2;
snd_buf_frame_size = 0;
} else {
send_to_sndbuf(audio_buf,
&g_buff[g_buff_frame_start * 2], avail_frame, 2);
snd_buf_frame_size -= avail_frame;
audio_buf += avail_frame * 2;
if (stream.buffer == NULL || stream.error == MAD_ERROR_BUFLEN) {
size_t read_size, remaining = 0;
uint8_t *read_start;
int bufsize;
if (stream.next_frame != NULL) {
remaining = stream.bufend - stream.next_frame;
memmove(g_input_buff, stream.next_frame, remaining);
read_start = g_input_buff + remaining;
read_size = BUFF_SIZE - remaining;
} else {
read_size = BUFF_SIZE;
read_start = g_input_buff;
remaining = 0;
}
if (mp3_data.use_buffer)
bufsize =
buffered_reader_read(mp3_data.r, read_start, read_size);
else
bufsize = xrIoRead(mp3_data.fd, read_start, read_size);
if (bufsize <= 0) {
__end();
return -1;
}
if (bufsize < read_size) {
uint8_t *guard = read_start + read_size;
memset(guard, 0, MAD_BUFFER_GUARD);
read_size += MAD_BUFFER_GUARD;
}
mad_stream_buffer(&stream, g_input_buff, read_size + remaining);
stream.error = 0;
}
ret = mad_frame_decode(&frame, &stream);
if (ret == -1) {
if (MAD_RECOVERABLE(stream.error)
|| stream.error == MAD_ERROR_BUFLEN) {
if (stream.error == MAD_ERROR_LOSTSYNC) {
long tagsize = id3_tag_query(stream.this_frame,
stream.bufend -
stream.this_frame);
if (tagsize > 0) {
mad_stream_skip(&stream, tagsize);
}
if (mad_header_decode(&frame.header, &stream) == -1) {
if (stream.error != MAD_ERROR_BUFLEN) {
if (!MAD_RECOVERABLE(stream.error)) {
__end();
return -1;
}
}
} else {
stream.error = MAD_ERROR_NONE;
}
}
g_buff_frame_size = 0;
g_buff_frame_start = 0;
continue;
} else {
__end();
return -1;
}
}
output = &g_buff[0];
if (stream.error != MAD_ERROR_NONE) {
continue;
}
mad_synth_frame(&synth, &frame);
for (i = 0; i < synth.pcm.length; i++) {
signed short sample;
if (MAD_NCHANNELS(&frame.header) == 2) {
/* Left channel */
sample = MadFixedToSshort(synth.pcm.samples[0][i]);
*(output++) = sample;
sample = MadFixedToSshort(synth.pcm.samples[1][i]);
*(output++) = sample;
} else {
sample = MadFixedToSshort(synth.pcm.samples[0][i]);
*(output++) = sample;
*(output++) = sample;
}
}
g_buff_frame_size = synth.pcm.length;
g_buff_frame_start = 0;
incr = frame.header.duration.seconds;
incr +=
mad_timer_fraction(frame.header.duration,
MAD_UNITS_MILLISECONDS) / 1000.0;
g_play_time += incr;
add_bitrate(&g_inst_br, frame.header.bitrate, incr);
}
}
return 0;
}
void LibMadWrapper::render(pcm_t *const bufferToFill, const uint32_t Channels, frame_t framesToRender)
{
framesToRender = min(framesToRender, this->getFrames() - this->framesAlreadyRendered);
int32_t *pcm = static_cast<int32_t *>(bufferToFill);
// the outer loop, used for decoding and synthesizing MPEG frames
while (framesToRender > 0 && !this->stopFillBuffer)
{
// write back tempbuffer, i.e. frames weve buffered from previous calls to libmad (necessary due to inelegant API of libmad, i.e. cant tell how many frames to render during one call)
{
const size_t itemsToCpy = min<size_t>(this->tempBuf.size(), framesToRender * Channels);
memcpy(pcm, this->tempBuf.data(), itemsToCpy * sizeof(int32_t));
this->tempBuf.erase(this->tempBuf.begin(), this->tempBuf.begin() + itemsToCpy);
const size_t framesCpyd = itemsToCpy / Channels;
framesToRender -= framesCpyd;
this->framesAlreadyRendered += framesCpyd;
// again: adjust position
pcm += itemsToCpy;
}
int framesToDoNow = (framesToRender / gConfig.FramesToRender) > 0 ? gConfig.FramesToRender : framesToRender % gConfig.FramesToRender;
if (framesToDoNow == 0)
{
continue;
}
int ret = mad_frame_decode(&this->frame.Value, this->stream);
if (ret != 0)
{
if (this->stream->error == MAD_ERROR_LOSTSYNC)
{
long tagsize = id3_tag_query(this->stream->this_frame, this->stream->bufend - this->stream->this_frame);
if (tagsize > 0)
{
mad_stream_skip(this->stream, tagsize);
continue;
}
}
string errstr = mad_stream_errorstr(this->stream);
if (MAD_RECOVERABLE(this->stream->error))
{
errstr += " (recoverable)";
CLOG(LogLevel_t::Info, errstr);
continue;
}
else
{
errstr += " (not recoverable)";
CLOG(LogLevel_t::Warning, errstr);
break;
}
}
mad_synth_frame(&this->synth.Value, &this->frame.Value);
/* save PCM samples from synth.pcm */
/* &synth.pcm->samplerate contains the sampling frequency */
unsigned short nsamples = this->synth->pcm.length;
mad_fixed_t const *left_ch = this->synth->pcm.samples[0];
mad_fixed_t const *right_ch = this->synth->pcm.samples[1];
unsigned int item = 0;
/* audio normalization */
const float absoluteGain = (numeric_limits<int32_t>::max()) / (numeric_limits<int32_t>::max() * this->gainCorrection);
for (;
!this->stopFillBuffer &&
framesToDoNow > 0 && // frames left during this loop
framesToRender > 0 && // frames left during this call
nsamples > 0; // frames left from libmad
framesToRender--, nsamples--, framesToDoNow--)
{
int32_t sample;
/* output sample(s) in 24-bit signed little-endian PCM */
sample = LibMadWrapper::toInt24Sample(*left_ch++);
sample = gConfig.useAudioNormalization ? floor(sample * absoluteGain) : sample;
pcm[item++] = sample;
if (Channels == 2) // our buffer is for 2 channels
{
if (this->synth.Value.pcm.channels == 2) // ...but did mad also decoded for 2 channels?
{
sample = LibMadWrapper::toInt24Sample(*right_ch++);
sample = gConfig.useAudioNormalization ? floor(sample * absoluteGain) : sample;
pcm[item++] = sample;
}
else
{
// what? only one channel in a stereo file? well then: pseudo stereo
pcm[item++] = sample;
CLOG(LogLevel_t::Warning, "decoded only one channel, though this is a stereo file!");
}
}
this->framesAlreadyRendered++;
}
pcm += item /* % this->count*/;
// "bufferToFill" (i.e. "pcm") seems to be full, drain the rest pcm samples from libmad and temporarily save them
while (!this->stopFillBuffer && nsamples > 0)
{
int32_t sample;
/* output sample(s) in 24-bit signed little-endian PCM */
sample = LibMadWrapper::toInt24Sample(*left_ch++);
this->tempBuf.push_back(gConfig.useAudioNormalization ? floor(sample * absoluteGain) : sample);
if (Channels == 2)
{
sample = LibMadWrapper::toInt24Sample(*right_ch++);
this->tempBuf.push_back(gConfig.useAudioNormalization ? floor(sample * absoluteGain) : sample);
}
/* DONT do this: this->framesAlreadyRendered++; since we use framesAlreadyRendered as offset for "bufferToFill"*/
nsamples--;
}
if (item > this->count)
{
CLOG(LogLevel_t::Error, "THIS SHOULD NEVER HAPPEN: read " << item << " items but only expected " << this->count << "\n");
break;
}
}
}
static void mp3_parse_id3(struct mp3_data *data, size_t tagsize,
struct tag **mpd_tag,
struct replay_gain_info **replay_gain_info_r)
{
struct id3_tag *id3_tag = NULL;
id3_length_t count;
id3_byte_t const *id3_data;
id3_byte_t *allocated = NULL;
count = data->stream.bufend - data->stream.this_frame;
if (tagsize <= count) {
id3_data = data->stream.this_frame;
mad_stream_skip(&(data->stream), tagsize);
} else {
allocated = g_malloc(tagsize);
memcpy(allocated, data->stream.this_frame, count);
mad_stream_skip(&(data->stream), count);
while (count < tagsize) {
size_t len;
len = decoder_read(data->decoder, data->input_stream,
allocated + count, tagsize - count);
if (len == 0)
break;
else
count += len;
}
if (count != tagsize) {
g_debug("error parsing ID3 tag");
g_free(allocated);
return;
}
id3_data = allocated;
}
id3_tag = id3_tag_parse(id3_data, tagsize);
if (id3_tag == NULL) {
g_free(allocated);
return;
}
if (mpd_tag) {
struct tag *tmp_tag = tag_id3_import(id3_tag);
if (tmp_tag != NULL) {
if (*mpd_tag != NULL)
tag_free(*mpd_tag);
*mpd_tag = tmp_tag;
}
}
if (replay_gain_info_r) {
struct replay_gain_info *tmp_rgi =
parse_id3_replay_gain_info(id3_tag);
if (tmp_rgi != NULL) {
if (*replay_gain_info_r)
replay_gain_info_free(*replay_gain_info_r);
*replay_gain_info_r = tmp_rgi;
}
}
id3_tag_delete(id3_tag);
g_free(allocated);
}
static void mp3_parse_id3(struct mp3_data *data, size_t tagsize,
struct tag **mpd_tag)
{
#ifdef HAVE_ID3TAG
struct id3_tag *id3_tag = NULL;
id3_length_t count;
id3_byte_t const *id3_data;
id3_byte_t *allocated = NULL;
count = data->stream.bufend - data->stream.this_frame;
if (tagsize <= count) {
id3_data = data->stream.this_frame;
mad_stream_skip(&(data->stream), tagsize);
} else {
allocated = g_malloc(tagsize);
memcpy(allocated, data->stream.this_frame, count);
mad_stream_skip(&(data->stream), count);
while (count < tagsize) {
size_t len;
len = decoder_read(data->decoder, data->input_stream,
allocated + count, tagsize - count);
if (len == 0)
break;
else
count += len;
}
if (count != tagsize) {
g_debug("error parsing ID3 tag");
g_free(allocated);
return;
}
id3_data = allocated;
}
id3_tag = id3_tag_parse(id3_data, tagsize);
if (id3_tag == NULL) {
g_free(allocated);
return;
}
if (mpd_tag) {
struct tag *tmp_tag = tag_id3_import(id3_tag);
if (tmp_tag != NULL) {
if (*mpd_tag != NULL)
tag_free(*mpd_tag);
*mpd_tag = tmp_tag;
}
}
if (data->decoder != NULL) {
struct replay_gain_info rgi;
char *mixramp_start;
char *mixramp_end;
float replay_gain_db = 0;
if (parse_id3_replay_gain_info(&rgi, id3_tag)) {
replay_gain_db = decoder_replay_gain(data->decoder, &rgi);
data->found_replay_gain = true;
}
if (parse_id3_mixramp(&mixramp_start, &mixramp_end, id3_tag)) {
g_debug("setting mixramp_tags");
decoder_mixramp(data->decoder, replay_gain_db,
mixramp_start, mixramp_end);
}
}
id3_tag_delete(id3_tag);
g_free(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 = data->stream.bufend - data->stream.this_frame;
if (tagsize <= count) {
mad_stream_skip(&data->stream, tagsize);
} else {
mad_stream_skip(&data->stream, count);
while (count < tagsize) {
size_t len = tagsize - count;
char ignored[1024];
if (len > sizeof(ignored))
len = sizeof(ignored);
len = decoder_read(data->decoder, data->input_stream,
ignored, len);
if (len == 0)
break;
else
count += len;
}
}
#endif
}
/* Handle first-stage decoding: extracting the MP3 frame data. */
int RageSoundReader_MP3::do_mad_frame_decode( bool headers_only )
{
int bytes_read = 0;
while(1)
{
int ret;
/* Always actually decode the first packet, so we cleanly parse Xing tags. */
if( headers_only && !mad->first_frame )
ret=mad_header_decode( &mad->Frame.header,&mad->Stream );
else
ret=mad_frame_decode( &mad->Frame,&mad->Stream );
if( ret == -1 && (mad->Stream.error == MAD_ERROR_BUFLEN || mad->Stream.error == MAD_ERROR_BUFPTR) )
{
if( bytes_read > 25000 )
{
/* We've read this much without actually getting a frame; error. */
SetError( "Can't find data" );
return -1;
}
ret = fill_buffer();
if( ret <= 0 )
return ret;
bytes_read += ret;
continue;
}
if( ret == -1 && mad->Stream.error == MAD_ERROR_LOSTSYNC )
{
/* This might be an ID3V2 tag. */
const int tagsize = id3_tag_query(mad->Stream.this_frame,
mad->Stream.bufend - mad->Stream.this_frame);
if( tagsize )
{
mad_stream_skip(&mad->Stream, tagsize);
/* Don't count the tagsize against the max-read-per-call figure. */
bytes_read -= tagsize;
continue;
}
}
if( ret == -1 && mad->Stream.error == MAD_ERROR_BADDATAPTR )
{
/*
* Something's corrupt. One cause of this is cutting an MP3 in the middle
* without reencoding; the first two frames will reference data from previous
* frames that have been removed. The frame is valid--we can get a header from
* it, we just can't synth useful data.
*
* BASS pretends the bad frames are silent. Emulate that, for compatibility.
*/
ret = 0; /* pretend success */
}
if( !ret )
{
/* OK. */
if( mad->first_frame )
{
/* We're at the beginning. Is this a Xing tag? */
if(handle_first_frame())
{
/* The first frame contained a header. Continue searching. */
continue;
}
/* We've decoded the first frame of data.
*
* We want mad->Timer to represent the timestamp of the first sample of the
* currently decoded frame. Don't increment mad->Timer on the first frame,
* or it'll be the time of the *next* frame. (All frames have the same
* duration.) */
mad->first_frame = false;
mad->Timer = mad_timer_zero;
mad->header_bytes = get_this_frame_byte(mad);
}
else
{
mad_timer_add( &mad->Timer,mad->Frame.header.duration );
}
fill_frame_index_cache( mad );
return 1;
}
if( mad->Stream.error == MAD_ERROR_BADCRC )
{
/* XXX untested */
mad_frame_mute(&mad->Frame);
mad_synth_mute(&mad->Synth);
continue;
}
if( !MAD_RECOVERABLE(mad->Stream.error) )
{
/* We've received an unrecoverable error. */
SetError( mad_stream_errorstr(&mad->Stream) );
return -1;
}
}
}
int MP3Decoder::mp3_decode(unsigned char const *inData, unsigned long inDataLength,
unsigned char *outData, unsigned long *outDataLength) {
int result = -1;
unsigned long curOutDataIndex = 0; // 当前已输出数据的index
unsigned long curInDataRemaining = inDataLength;// 当前输入数据剩余数据量
if (_isClearPreDeocodeBuffer) {
Stream.next_frame = NULL;
_isClearPreDeocodeBuffer = false;
}
/* 开始解码 */
do {
/* 如果缓冲区空了或不足一帧数据, 就向缓冲区填充数据 */
if (Stream.buffer == NULL || Stream.error == MAD_ERROR_BUFLEN) {
size_t BufferSize; /* 缓冲区大小 */
size_t Remaining; /* 帧剩余数据 */
unsigned char *BufferStart; /* 头指针 */
if (Stream.next_frame != NULL) // 还有上一帧的缓存
{
/* 把剩余没解码完的数据补充到这次的缓冲区中 */
Remaining = Stream.bufend - Stream.next_frame;
memmove(Mp3_InputBuffer, Stream.next_frame, Remaining);
BufferStart = Mp3_InputBuffer + Remaining;
BufferSize = INPUT_BUFFER_SIZE - Remaining;
}
else // 没有上一帧的缓存
{
/* 设置了缓冲区地址, 但还没有填充数据 */
BufferSize = INPUT_BUFFER_SIZE;
BufferStart = Mp3_InputBuffer;
Remaining = 0;
}
/* 从输入数据中读取数据并填充缓冲区 */
if (curInDataRemaining == 0) {
BufferSize = 0; // 没有数据可读取
}
else {
if (curInDataRemaining >= BufferSize) // 剩余的数据量满足准备读取的数据量
{
memcpy(BufferStart, inData + (inDataLength - curInDataRemaining), BufferSize);
curInDataRemaining -= BufferSize;
}
else // 剩余的数据量不足，全部取 出来
{
memcpy(BufferStart, inData + (inDataLength - curInDataRemaining),
curInDataRemaining);
BufferSize = curInDataRemaining;
curInDataRemaining = 0;
}
}
if (BufferSize <= 0) // 未读取到数据，直接返回
{
/*printf("文件读取失败\n");
exit(-1);*/
result = 0;
break;
}
mad_stream_buffer(&Stream, Mp3_InputBuffer, BufferSize + Remaining);
Stream.error = MAD_ERROR_NONE;
}
if (mad_frame_decode(&Frame, &Stream)) {
// 解码出错
if (MAD_RECOVERABLE(Stream.error)) {
// 可恢复的错误，继续执行
continue;
}
else {
if (Stream.error == MAD_ERROR_BUFLEN) {
continue; /* buffer解码光了, 需要继续填充 */
}
else if (Stream.error == MAD_ERROR_LOSTSYNC) {
// 丢失同步，这里可以不处理，因此该错误属于可恢复的错误
int tagsize = 0;
//tagsize = id3_tag_query(Stream.this_frame, Stream.bufend - Stream.this_frame);
if (tagsize > 0) {
mad_stream_skip(&Stream, tagsize);
}
continue;
}
else {
// 严重错误，无法继续解码
result = -1;
break;
}
}
}
/* 设置每帧的播放时间 */
//mad_timer_add(&Timer, Frame.header.duration);
/* 解码成音频数据 */
mad_synth_frame(&Synth, &Frame);
struct mad_pcm *pcm = &Synth.pcm;
unsigned int nchannels, nsamples;
mad_fixed_t const *left_ch, *right_ch;
/* pcm->samplerate contains the sampling frequency */
nchannels = pcm->channels;
nsamples = pcm->length;
left_ch = pcm->samples[0];
right_ch = pcm->samples[1];
int curDataLen = pcm->length * pcm->channels * sizeof(short);
short *buf = (short *) malloc(curDataLen);
// 将解码后的数据进行填充
int i = 0;
while (nsamples--) {
signed int sample;
// output sample(s) in 16-bit signed little-endian PCM
sample = scale(*left_ch++);
buf[i++] = sample & 0xFFFF;
if (nchannels == 2) {
sample = scale(*right_ch++);
buf[i++] = sample & 0xFFFF;
}
}
memcpy(outData + curOutDataIndex, buf, curDataLen);
curOutDataIndex += curDataLen;
*outDataLength = curOutDataIndex;
free(buf);
} while (1);
return result;
}
int64 MadDecoder::getDurationMs(unsigned char* buffer, size_t bufferSize)
{
struct mad_stream madStream;
struct mad_frame madFrame;
struct mad_header madHeader;
mad_timer_t time = mad_timer_zero;
bool depadded = false;
bool vbr = false;
size_t tagsize = 0;
size_t consumed = 0;
size_t numFrames = 0;
size_t initialBitrate = 0;
mad_stream_init(&madStream);
mad_header_init(&madHeader);
mad_frame_init(&madFrame);
do // Read data from the MP3 file
{
int padding = 0;
size_t leftover = madStream.bufend - madStream.next_frame;
memcpy(buffer, madStream.this_frame, leftover);
int bytesRead = fread(buffer + leftover, (size_t)1, bufferSize - leftover, handle_);
if (bytesRead <= 0) {
break;
}
for (; !depadded && padding < bytesRead && !buffer[padding]; ++padding);
depadded = true;
mad_stream_buffer(&madStream, buffer + padding, leftover + bytesRead - padding);
while (true) // decode frame headers
{
madStream.error = MAD_ERROR_NONE;
if (mad_header_decode(&madHeader, &madStream) == -1)
{
if (madStream.error == MAD_ERROR_BUFLEN) // Normal behaviour; get some more data from the file
break;
if (MAD_RECOVERABLE(madStream.error) == 0)
break;
if (madStream.error == MAD_ERROR_LOSTSYNC)
{
unsigned available = (madStream.bufend - madStream.this_frame);
tagsize = getId3TagSize(madStream.this_frame, (size_t)available);
if (tagsize) // It's some ID3 tags, so just skip
{
if (tagsize >= available) {
_fseeki64(handle_, (int64)(tagsize - available), SEEK_CUR);
depadded = false;
}
mad_stream_skip(&madStream, std::min(tagsize, available));
}
}
continue; // not an audio frame
}
mad_timer_add(&time, madHeader.duration);
consumed += madStream.next_frame - madStream.this_frame;
if (numFrames == 0) {
initialBitrate = madHeader.bitrate;
// Get the precise frame count from the XING header if present
madFrame.header = madHeader;
if (mad_frame_decode(&madFrame, &madStream) == -1)
{
if (MAD_RECOVERABLE(madStream.error) == 0) {
break;
}
}
if ((numFrames = xingFrames(madStream.anc_ptr, madStream.anc_bitlen)))
{
mad_timer_multiply(&time, (signed long)numFrames);
break;
}
}
else {
vbr |= madHeader.bitrate != initialBitrate;
}
// If not VBR, we can time just a few frames then extrapolate (not exact!)
if (++numFrames == 25 && !vbr)
{
struct stat st;
fstat(fileno(handle_), &st);
timerMultiply(&time, (double)(st.st_size - tagsize) / consumed);
break;
}
} // while(true)
} while (madStream.error == MAD_ERROR_BUFLEN);
mad_frame_finish(&madFrame);
mad_header_finish(&madHeader);
mad_stream_finish(&madStream);
rewind(handle_);
return mad_timer_count(time, MAD_UNITS_MILLISECONDS);
}
