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Refactoring the decoder to create opus_packet_parse()

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This commit is contained in:
Jean-Marc Valin 2011-08-08 11:57:13 -04:00
parent 5e9f7fc31d
commit 4154dad41e
2 changed files with 132 additions and 87 deletions
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4
src/opus.h
View file

@ -217,6 +217,10 @@ OPUS_EXPORT int opus_decoder_ctl(OpusDecoder *st, int request, ...);
OPUS_EXPORT void opus_decoder_destroy(OpusDecoder *st); OPUS_EXPORT void opus_decoder_destroy(OpusDecoder *st);
OPUS_EXPORT int opus_packet_parse(const unsigned char *data, int len,
unsigned char *out_toc, const unsigned char *frames[48],
short size[48], const unsigned char **payload);
OPUS_EXPORT int opus_packet_get_bandwidth(const unsigned char *data); OPUS_EXPORT int opus_packet_get_bandwidth(const unsigned char *data);
OPUS_EXPORT int opus_packet_get_samples_per_frame(const unsigned char *data, int Fs); OPUS_EXPORT int opus_packet_get_samples_per_frame(const unsigned char *data, int Fs);
OPUS_EXPORT int opus_packet_get_nb_channels(const unsigned char *data); OPUS_EXPORT int opus_packet_get_nb_channels(const unsigned char *data);

215
src/opus_decoder.c
View file

@ -412,12 +412,131 @@ static int parse_size(const unsigned char *data, int len, short *size)
} }
} }
int opus_packet_parse(const unsigned char *data, int len,
unsigned char *out_toc, const unsigned char *frames[48],
short size[48], const unsigned char **payload)
{
int i, bytes;
int count;
unsigned char ch, toc;
int framesize;
if (size==NULL)
return OPUS_BAD_ARG;
framesize = opus_packet_get_samples_per_frame(data, 48000);
toc = *data++;
len--;
switch (toc&0x3)
{
/* One frame */
case 0:
count=1;
size[0] = len;
break;
/* Two CBR frames */
case 1:
count=2;
if (len&0x1)
return OPUS_CORRUPTED_DATA;
size[0] = size[1] = len/2;
break;
/* Two VBR frames */
case 2:
count = 2;
bytes = parse_size(data, len, size);
len -= bytes;
if (size[0]<0 || size[0] > len)
return OPUS_CORRUPTED_DATA;
data += bytes;
size[1] = len-size[0];
break;
/* Multiple CBR/VBR frames (from 0 to 120 ms) */
case 3:
if (len<1)
return OPUS_CORRUPTED_DATA;
/* Number of frames encoded in bits 0 to 5 */
ch = *data++;
count = ch&0x3F;
if (count <= 0 || framesize*count > 5760)
return OPUS_CORRUPTED_DATA;
len--;
/* Padding flag is bit 6 */
if (ch&0x40)
{
int padding=0;
int p;
do {
if (len<=0)
return OPUS_CORRUPTED_DATA;
p = *data++;
len--;
padding += p==255 ? 254: p;
} while (p==255);
len -= padding;
}
if (len<0)
return OPUS_CORRUPTED_DATA;
/* VBR flag is bit 7 */
if (ch&0x80)
{
/* VBR case */
int last_size=len;
for (i=0;i<count-1;i++)
{
bytes = parse_size(data, len, size+i);
len -= bytes;
if (size[i]<0 || size[i] > len)
return OPUS_CORRUPTED_DATA;
data += bytes;
last_size -= bytes+size[i];
}
if (last_size<0)
return OPUS_CORRUPTED_DATA;
size[count-1]=last_size;
} else {
/* CBR case */
int sz = len/count;
if (sz*count!=len)
return OPUS_CORRUPTED_DATA;
for (i=0;i<count;i++)
size[i] = sz;
}
break;
}
/* Because it's not encoded explicitly, it's possible the size of the
last packet (or all the packets, for the CBR case) is larger than
1275.
Reject them here.*/
if (size[count-1] > 1275)
return OPUS_CORRUPTED_DATA;
if (frames)
{
for (i=0;i<count;i++)
{
frames[i] = data;
data += size[i];
}
}
if (out_toc)
*out_toc = toc;
if (payload)
*payload = data;
return count;
}
int opus_decode(OpusDecoder *st, const unsigned char *data, int opus_decode(OpusDecoder *st, const unsigned char *data,
int len, opus_int16 *pcm, int frame_size, int decode_fec) int len, opus_int16 *pcm, int frame_size, int decode_fec)
{ {
int i, bytes, nb_samples; int i, nb_samples;
int count; int count;
unsigned char ch, toc; unsigned char toc;
/* 48 x 2.5 ms = 120 ms */ /* 48 x 2.5 ms = 120 ms */
short size[48]; short size[48];
if (len==0 || data==NULL) if (len==0 || data==NULL)
@ -428,91 +547,11 @@ int opus_decode(OpusDecoder *st, const unsigned char *data,
st->bandwidth = opus_packet_get_bandwidth(data); st->bandwidth = opus_packet_get_bandwidth(data);
st->frame_size = opus_packet_get_samples_per_frame(data, st->Fs); st->frame_size = opus_packet_get_samples_per_frame(data, st->Fs);
st->stream_channels = opus_packet_get_nb_channels(data); st->stream_channels = opus_packet_get_nb_channels(data);
toc = *data++;
len--; count = opus_packet_parse(data, len, &toc, NULL, size, &data);
switch (toc&0x3) if (count < 0)
{ return count;
/* One frame */
case 0:
count=1;
size[0] = len;
break;
/* Two CBR frames */
case 1:
count=2;
if (len&0x1)
return OPUS_CORRUPTED_DATA;
size[0] = size[1] = len/2;
break;
/* Two VBR frames */
case 2:
count = 2;
bytes = parse_size(data, len, size);
len -= bytes;
if (size[0]<0 || size[0] > len)
return OPUS_CORRUPTED_DATA;
data += bytes;
size[1] = len-size[0];
break;
/* Multiple CBR/VBR frames (from 0 to 120 ms) */
case 3:
if (len<1)
return OPUS_CORRUPTED_DATA;
/* Number of frames encoded in bits 0 to 5 */
ch = *data++;
count = ch&0x3F;
if (count <= 0 || st->frame_size*count*25 > 3*st->Fs)
return OPUS_CORRUPTED_DATA;
len--;
/* Padding flag is bit 6 */
if (ch&0x40)
{
int padding=0;
int p;
do {
if (len<=0)
return OPUS_CORRUPTED_DATA;
p = *data++;
len--;
padding += p==255 ? 254: p;
} while (p==255);
len -= padding;
}
if (len<0)
return OPUS_CORRUPTED_DATA;
/* VBR flag is bit 7 */
if (ch&0x80)
{
/* VBR case */
int last_size=len;
for (i=0;i<count-1;i++)
{
bytes = parse_size(data, len, size+i);
len -= bytes;
if (size[i]<0 || size[i] > len)
return OPUS_CORRUPTED_DATA;
data += bytes;
last_size -= bytes+size[i];
}
if (last_size<0)
return OPUS_CORRUPTED_DATA;
size[count-1]=last_size;
} else {
/* CBR case */
int sz = len/count;
if (sz*count!=len)
return OPUS_CORRUPTED_DATA;
for (i=0;i<count;i++)
size[i] = sz;
}
break;
}
/* Because it's not encoded explicitly, it's possible the size of the
last packet (or all the packets, for the CBR case) is larger than
1275.
Reject them here.*/
if (size[count-1] > MAX_PACKET)
return OPUS_CORRUPTED_DATA;
if (count*st->frame_size > frame_size) if (count*st->frame_size > frame_size)
return OPUS_BAD_ARG; return OPUS_BAD_ARG;
nb_samples=0; nb_samples=0;
@ -528,6 +567,8 @@ int opus_decode(OpusDecoder *st, const unsigned char *data,
} }
return nb_samples; return nb_samples;
} }
int opus_decoder_ctl(OpusDecoder *st, int request, ...) int opus_decoder_ctl(OpusDecoder *st, int request, ...)
{ {
va_list ap; va_list ap;