winamp/Src/mp3-mpg123/nsvmain.cpp

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2024-09-24 12:54:57 +00:00
#include "../nsv/nsvlib.h"
#include "../nsv/dec_if.h"
#include "nsvmain.h"
#include "../nsutil/pcm.h"
MP3_Decoder::MP3_Decoder()
{
decoder = mpg123_new(NULL, NULL);
long flags = MPG123_QUIET|MPG123_FORCE_FLOAT|MPG123_SKIP_ID3V2|MPG123_IGNORE_STREAMLENGTH|MPG123_IGNORE_INFOFRAME;
mpg123_param(decoder, MPG123_FLAGS, flags, 0);
mpg123_param(decoder, MPG123_RVA, MPG123_RVA_OFF, 0);
memset(pcm_buf, 0, sizeof(pcm_buf));
mpg123_open_feed(decoder);
fused = 0; pcm_buf_used = 0; pcm_offs = 0;
}
int MP3_Decoder::decode(void *in, int in_len,
void *out, int *out_len,
unsigned int out_fmt[8])
{
int rval = 1;
if (fused < in_len)
{
int l = 4096;
if (l > in_len - fused) l = in_len - fused;
if (l) mpg123_feed(decoder, (unsigned char *)in + fused, l);
fused += l;
}
if (!pcm_buf_used)
{
mpg123_read(decoder, (unsigned char *)pcm_buf, sizeof(pcm_buf), &pcm_buf_used);
pcm_offs = 0;
}
if (pcm_buf_used)
{
size_t numSamples = *out_len / 2;
if (numSamples > (pcm_buf_used/sizeof(float)))
numSamples = pcm_buf_used/sizeof(float);
nsutil_pcm_FloatToInt_Interleaved(out, pcm_buf+pcm_offs, 16, numSamples);
pcm_buf_used -= numSamples*sizeof(float);
pcm_offs += (int)numSamples;
*out_len = 2*(int)numSamples;
}
else
{
if (fused >= in_len) { fused = 0; rval = 0; }
*out_len = 0;
}
mpg123_frameinfo frameInfo;
if (mpg123_info(decoder, &frameInfo) == MPG123_OK) {
int nch = (frameInfo.mode == MPG123_M_MONO)?1:2;
int srate = frameInfo.rate;
out_fmt[0] = (nch && srate) ? NSV_MAKETYPE('P', 'C', 'M', ' ') : 0;
out_fmt[1] = srate;
out_fmt[2] = nch;
out_fmt[3] = (nch && srate) ? 16 : 0;
out_fmt[4] = frameInfo.bitrate;
}
return rval;
}
void MP3_Decoder::flush()
{
fused = 0;
pcm_buf_used = 0;
pcm_offs = 0;
mpg123_open_feed(decoder);
}
extern "C"
{
__declspec(dllexport) IAudioDecoder *CreateAudioDecoder(unsigned int fmt, IAudioOutput **output)
{
switch (fmt)
{
case NSV_MAKETYPE('M', 'P', '3', ' '):
return new MP3_Decoder;
default:
return NULL;
}
}
__declspec(dllexport) void DeleteAudioDecoder(IAudioDecoder *decoder)
{
if (decoder)
delete decoder;
}
}