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mpc: provide 24 bit samples

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Similar to libmad, libmpcdec provides samples with higher quality than
16 bit.  Send 24 bit samples to MPD, which allows MPD to apply
dithering just in case the output devices are only 16 bit capable.
This commit is contained in:
Max Kellermann 2008-10-30 08:45:00 +01:00
parent 0db07a920e
commit 5f6383d68c
1 changed files with 6 additions and 7 deletions
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13
src/decoder/mpc_plugin.c
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@ -63,13 +63,13 @@ static mpc_int32_t mpc_getsize_cb(void *vdata)
} }
/* this _looks_ performance-critical, don't de-inline -- eric */ /* this _looks_ performance-critical, don't de-inline -- eric */
static inline int16_t convertSample(MPC_SAMPLE_FORMAT sample) static inline int32_t convertSample(MPC_SAMPLE_FORMAT sample)
{ {
/* only doing 16-bit audio for now */ /* only doing 16-bit audio for now */
int32_t val; int32_t val;
enum { enum {
bits = 16, bits = 24,
}; };
const int clip_min = -1 << (bits - 1); const int clip_min = -1 << (bits - 1);
@ -114,7 +114,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
char chunk[MPC_CHUNK_SIZE]; char chunk[MPC_CHUNK_SIZE];
int chunkpos = 0; int chunkpos = 0;
long bitRate = 0; long bitRate = 0;
int16_t *dest = (int16_t *) chunk; int32_t *dest = (int32_t *) chunk;
unsigned long samplePos = 0; unsigned long samplePos = 0;
mpc_uint32_t vbrUpdateAcc; mpc_uint32_t vbrUpdateAcc;
mpc_uint32_t vbrUpdateBits; mpc_uint32_t vbrUpdateBits;
@ -152,7 +152,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
return true; return true;
} }
audio_format.bits = 16; audio_format.bits = 24;
audio_format.channels = info.channels; audio_format.channels = info.channels;
audio_format.sample_rate = info.sample_freq; audio_format.sample_rate = info.sample_freq;
@ -170,7 +170,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
samplePos = decoder_seek_where(mpd_decoder) * samplePos = decoder_seek_where(mpd_decoder) *
audio_format.sample_rate; audio_format.sample_rate;
if (mpc_decoder_seek_sample(&decoder, samplePos)) { if (mpc_decoder_seek_sample(&decoder, samplePos)) {
dest = (int16_t *) chunk; dest = (int32_t *)chunk;
chunkpos = 0; chunkpos = 0;
decoder_command_finished(mpd_decoder); decoder_command_finished(mpd_decoder);
} else } else
@ -193,7 +193,6 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
ret *= 2; ret *= 2;
for (i = 0; i < ret; i++) { for (i = 0; i < ret; i++) {
/* 16 bit audio again */
*dest++ = convertSample(sample_buffer[i]); *dest++ = convertSample(sample_buffer[i]);
chunkpos += sizeof(*dest); chunkpos += sizeof(*dest);
@ -211,7 +210,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
bitRate, replayGainInfo); bitRate, replayGainInfo);
chunkpos = 0; chunkpos = 0;
dest = (int16_t *) chunk; dest = (int32_t *)chunk;
if (decoder_get_command(mpd_decoder) == DECODE_COMMAND_STOP) { if (decoder_get_command(mpd_decoder) == DECODE_COMMAND_STOP) {
eof = true; eof = true;
break; break;