ref: c2f685c83ddd0146d9707777d2fc8771b2dd8387
dir: /src/opus_header.c/
/* Copyright (C)2012 Xiph.Org Foundation
File: opus_header.c
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "opus_header.h"
#include <string.h>
#include <stdio.h>
/* Header contents:
- "OpusHead" (64 bits)
- version number (8 bits)
- Channels C (8 bits)
- Pre-skip (16 bits)
- Sampling rate (32 bits)
- Gain in dB (16 bits, S7.8)
- Mapping (8 bits, 0=single stream (mono/stereo) 1=Vorbis mapping,
2..254: reserved, 255: multistream with no mapping)
- if (mapping != 0)
- N = total number of streams (8 bits)
- M = number of paired streams (8 bits)
- C times channel origin
- if (C<2*M)
- stream = byte/2
- if (byte&0x1 == 0)
- left
else
- right
- else
- stream = byte-M
*/
typedef struct {
const unsigned char *data;
int maxlen;
int pos;
} ROPacket;
static int read_uint32(ROPacket *p, ogg_uint32_t *val)
{
if (p->pos>p->maxlen-4)
return 0;
*val = (ogg_uint32_t)p->data[p->pos ];
*val |= (ogg_uint32_t)p->data[p->pos+1]<< 8;
*val |= (ogg_uint32_t)p->data[p->pos+2]<<16;
*val |= (ogg_uint32_t)p->data[p->pos+3]<<24;
p->pos += 4;
return 1;
}
static int read_uint16(ROPacket *p, ogg_uint16_t *val)
{
if (p->pos>p->maxlen-2)
return 0;
*val = (ogg_uint16_t)p->data[p->pos ];
*val |= (ogg_uint16_t)p->data[p->pos+1]<<8;
p->pos += 2;
return 1;
}
static int read_chars(ROPacket *p, unsigned char *str, int nb_chars)
{
int i;
if (p->pos>p->maxlen-nb_chars)
return 0;
for (i=0;i<nb_chars;i++)
str[i] = p->data[p->pos++];
return 1;
}
int opus_header_parse(const unsigned char *packet, int len, OpusHeader *h)
{
int i;
char str[9];
ROPacket p;
unsigned char ch;
ogg_uint16_t shortval;
p.data = packet;
p.maxlen = len;
p.pos = 0;
str[8] = 0;
if (len<19)return 0;
read_chars(&p, (unsigned char*)str, 8);
if (memcmp(str, "OpusHead", 8)!=0)
return 0;
if (!read_chars(&p, &ch, 1))
return 0;
h->version = ch;
if((h->version&240) != 0) /* Only major version 0 supported. */
return 0;
if (!read_chars(&p, &ch, 1))
return 0;
h->channels = ch;
if (h->channels == 0)
return 0;
if (!read_uint16(&p, &shortval))
return 0;
h->preskip = shortval;
if (!read_uint32(&p, &h->input_sample_rate))
return 0;
if (!read_uint16(&p, &shortval))
return 0;
h->gain = (short)shortval;
if (!read_chars(&p, &ch, 1))
return 0;
h->channel_mapping = ch;
if (h->channel_mapping != 0)
{
if (!read_chars(&p, &ch, 1))
return 0;
if (ch<1)
return 0;
h->nb_streams = ch;
if (!read_chars(&p, &ch, 1))
return 0;
if (ch>h->nb_streams || (ch+h->nb_streams)>255)
return 0;
h->nb_coupled = ch;
/* Multi-stream support */
for (i=0;i<h->channels;i++)
{
if (!read_chars(&p, &h->stream_map[i], 1))
return 0;
if (h->stream_map[i]>(h->nb_streams+h->nb_coupled) && h->stream_map[i]!=255)
return 0;
}
} else {
if(h->channels>2)
return 0;
h->nb_streams = 1;
h->nb_coupled = h->channels>1;
h->stream_map[0]=0;
h->stream_map[1]=1;
}
/*For version 0/1 we know there won't be any more data
so reject any that have data past the end.*/
if ((h->version==0 || h->version==1) && p.pos != len)
return 0;
return 1;
}
/* This is just here because it's a convenient file linked by both opusenc and
opusdec (to guarantee this maps stays in sync). */
const int wav_permute_matrix[8][8] =
{
{0}, /* 1.0 mono */
{0,1}, /* 2.0 stereo */
{0,2,1}, /* 3.0 channel ('wide') stereo */
{0,1,2,3}, /* 4.0 discrete quadraphonic */
{0,2,1,3,4}, /* 5.0 surround */
{0,2,1,4,5,3}, /* 5.1 surround */
{0,2,1,5,6,4,3}, /* 6.1 surround */
{0,2,1,6,7,4,5,3} /* 7.1 surround (classic theater 8-track) */
};