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First attempt at gapless MP3 support using LAME header info.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6690 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen 2005-06-12 14:38:36 +00:00
parent 57f0ec1474
commit 7cdae1ac65
1 changed files with 40 additions and 9 deletions
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41
apps/plugins/codecmpa.c
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@ -172,7 +172,8 @@ const unsigned char *OutputBufferEnd=OutputBuffer+OUTPUT_BUFFER_SIZE;
mad_fixed_t mad_frame_overlap[2][32][18] IDATA_ATTR;
unsigned char mad_main_data[MAD_BUFFER_MDLEN] IDATA_ATTR;
/* TODO: what latency does layer 1 have? */
int mpeg_latency[3] = { 0, 481, 529 };
#ifdef USE_IRAM
extern char iramcopy[];
extern char iramstart[];
@ -185,6 +186,7 @@ extern char iramend[];
enum plugin_status plugin_start(struct plugin_api* api, void* parm)
{
struct codec_api *ci = (struct codec_api *)parm;
struct mp3info *info;
int Status=0;
size_t size;
int file_end;
@ -199,6 +201,7 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
#endif
int i;
int yieldcounter = 0;
int stop_skip, start_skip;
/* Generic plugin inititialisation */
@ -220,7 +223,6 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
ci->configure(CODEC_SET_FILEBUF_LIMIT, (int *)(1024*1024*2));
ci->configure(CODEC_SET_FILEBUF_CHUNKSIZE, (int *)(1024*16));
next_track:
memset(&Stream, 0, sizeof(struct mad_stream));
memset(&Frame, 0, sizeof(struct mad_frame));
memset(&Synth, 0, sizeof(struct mad_synth));
@ -235,6 +237,10 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
memset(mad_frame_overlap, 0, sizeof(mad_frame_overlap));
Frame.overlap = &mad_frame_overlap;
Stream.main_data = &mad_main_data;
/* This label might need to be moved above all the init code, but I don't
think reiniting the codec is necessary for MPEG. It might even be unwanted
for gapless playback */
next_track:
#ifdef DEBUG_GAPLESS
if (first)
@ -244,6 +250,7 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
first = false;
#endif
info = ci->mp3data;
first_frame = false;
file_end = 0;
OutputPtr = OutputBuffer;
@ -255,8 +262,28 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
ci->request_buffer(&size, ci->id3->first_frame_offset);
ci->advance_buffer(size);
if (info->enc_delay >= 0 && info->enc_padding >= 0) {
stop_skip = info->enc_padding - mpeg_latency[info->layer];
if (stop_skip < 0) stop_skip = 0;
start_skip = info->enc_delay + mpeg_latency[info->layer];
} else {
stop_skip = 0;
/* We want to skip this amount anyway */
start_skip = mpeg_latency[info->layer];
}
/* NOTE: currently this doesn't work, the below calculated samples_count
seems to be right, but sometimes libmad just can't supply us with
all the data we need... */
if (info->frame_count) {
/* TODO: 1152 is the frame size in samples for MPEG1 layer 2 and layer 3,
it's probably not correct at all for MPEG2 and layer 1 */
samplecount = info->frame_count*1152 - (start_skip + stop_skip);
samplesdone = ci->id3->elapsed * (ci->id3->frequency / 100) / 10;
} else {
samplecount = ci->id3->length * (ci->id3->frequency / 100) / 10;
samplesdone = ci->id3->elapsed * (ci->id3->frequency / 100) / 10;
}
/* rb->snprintf(buf2, sizeof(buf2), "sc: %d", samplecount);
rb->splash(0, true, buf2);
rb->snprintf(buf2, sizeof(buf2), "length: %d", ci->id3->length);
@ -345,18 +372,22 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parm)
//}
/* Convert MAD's numbers to an array of 16-bit LE signed integers */
for(i=0;i<Synth.pcm.length;i++)
/* We skip start_skip number of samples here, this should only happen for
very first frame in the stream. */
/* TODO: possible for start_skip to exceed one frames worth of samples? */
for (i = start_skip;i<Synth.pcm.length;i++)
{
start_skip = 0; /* not very elegant, and might want to keep this value */
samplesdone++;
//if (ci->mp3data->padding > 0) {
// ci->mp3data->padding--;
// continue ;
//}
if (!first_frame) {
/*if (!first_frame) {
if (detect_silence(Synth.pcm.samples[0][i]))
continue ;
first_frame = true;
}
}*/
/* Left channel */
Sample=scale(Synth.pcm.samples[0][i],&d0);