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Adding some packet parsing code

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This commit is contained in:
Jean-Marc Valin 2011-03-13 12:41:08 -04:00
parent 8ea67049c2
commit 0fe4078b30
2 changed files with 105 additions and 26 deletions
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7
src/opus.h
View file

@ -148,6 +148,13 @@ int opus_decoder_ctl(OpusDecoder *st, int request, ...);
void opus_decoder_destroy(OpusDecoder *st);
int opus_packet_get_bandwidth(const unsigned char *data);
int opus_packet_get_samples_per_frame(const unsigned char *data, int Fs);
int opus_packet_get_nb_channels(const unsigned char *data);
int opus_packet_get_nb_frames(const unsigned char packet[], int len);
int opus_decoder_get_nb_samples(const OpusDecoder *dec, const unsigned char packet[], int len);
#if OPUS_TEST_RANGE_CODER_STATE
int opus_encoder_get_final_range(OpusEncoder *st);
int opus_decoder_get_final_range(OpusDecoder *st);

120
src/opus_decoder.c
View file

@ -84,6 +84,22 @@ static void smooth_fade(const short *in1, const short *in2, short *out, int over
}
}
static int opus_packet_get_mode(const unsigned char *data)
{
int mode;
if (data[0]&0x80)
{
mode = MODE_CELT_ONLY;
} else if ((data[0]&0x60) == 0x60)
{
mode = MODE_HYBRID;
} else {
mode = MODE_SILK_ONLY;
}
return mode;
}
int opus_decode(OpusDecoder *st, const unsigned char *data,
int len, short *pcm, int frame_size, int decode_fec)
{
@ -109,32 +125,14 @@ int opus_decode(OpusDecoder *st, const unsigned char *data,
if (data != NULL)
{
/* Decoding mode/bandwidth/framesize from first byte */
if (data[0]&0x80)
mode =opus_packet_get_mode(data);
st->bandwidth = opus_packet_get_bandwidth(data);
audiosize = opus_packet_get_samples_per_frame(data, st->Fs);
st->stream_channels = opus_packet_get_nb_channels(data);
if (opus_packet_get_nb_frames(data, len)>1)
{
mode = MODE_CELT_ONLY;
st->bandwidth = BANDWIDTH_MEDIUMBAND + ((data[0]>>5)&0x3);
if (st->bandwidth == BANDWIDTH_MEDIUMBAND)
st->bandwidth = BANDWIDTH_NARROWBAND;
audiosize = ((data[0]>>3)&0x3);
audiosize = (st->Fs<<audiosize)/400;
} else if ((data[0]&0x60) == 0x60)
{
mode = MODE_HYBRID;
st->bandwidth = (data[0]&0x10) ? BANDWIDTH_FULLBAND : BANDWIDTH_SUPERWIDEBAND;
audiosize = (data[0]&0x08) ? st->Fs/50 : st->Fs/100;
} else {
mode = MODE_SILK_ONLY;
st->bandwidth = BANDWIDTH_NARROWBAND + ((data[0]>>5)&0x3);
audiosize = ((data[0]>>3)&0x3);
if (audiosize == 3)
audiosize = st->Fs*60/1000;
else
audiosize = (st->Fs<<audiosize)/100;
/* FIXME: Handle the case of multiple frames */
}
st->stream_channels = (data[0]&0x4) ? 2 : 1;
/*printf ("%d %d %d\n", st->mode, st->bandwidth, audiosize);*/
len -= 1;
data += 1;
@ -373,3 +371,77 @@ int opus_decoder_get_final_range(OpusDecoder *st)
return st->rangeFinal;
}
#endif
int opus_packet_get_bandwidth(const unsigned char *data)
{
int bandwidth;
if (data[0]&0x80)
{
bandwidth = BANDWIDTH_MEDIUMBAND + ((data[0]>>5)&0x3);
if (bandwidth == BANDWIDTH_MEDIUMBAND)
bandwidth = BANDWIDTH_NARROWBAND;
} else if ((data[0]&0x60) == 0x60)
{
bandwidth = (data[0]&0x10) ? BANDWIDTH_FULLBAND : BANDWIDTH_SUPERWIDEBAND;
} else {
bandwidth = BANDWIDTH_NARROWBAND + ((data[0]>>5)&0x3);
}
return bandwidth;
}
int opus_packet_get_samples_per_frame(const unsigned char *data, int Fs)
{
int audiosize;
if (data[0]&0x80)
{
audiosize = ((data[0]>>3)&0x3);
audiosize = (Fs<<audiosize)/400;
} else if ((data[0]&0x60) == 0x60)
{
audiosize = (data[0]&0x08) ? Fs/50 : Fs/100;
} else {
audiosize = ((data[0]>>3)&0x3);
if (audiosize == 3)
audiosize = Fs*60/1000;
else
audiosize = (Fs<<audiosize)/100;
}
return audiosize;
}
int opus_packet_get_nb_channels(const unsigned char *data)
{
return (data[0]&0x4) ? 2 : 1;
}
int opus_packet_get_nb_frames(const unsigned char packet[], int len)
{
int count;
if (len<1)
return OPUS_BAD_ARG;
count = packet[0]&0x3;
if (count==0)
return 1;
else if (count!=3)
return 2;
else if (len<2)
return OPUS_CORRUPTED_DATA;
else
return packet[1]&0x3F;
}
int opus_decoder_get_nb_samples(const OpusDecoder *dec, const unsigned char packet[], int len)
{
int samples;
int count = opus_packet_get_nb_frames(packet, len);
samples = count*opus_packet_get_samples_per_frame(packet, dec->Fs);
/* Can't have more than 120 ms */
if (samples*25 > dec->Fs*3)
return OPUS_CORRUPTED_DATA;
else
return samples;
}