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/**
* @file h263.c H.263 video codec (RFC 4629)
*
* Copyright (C) 2010 Alfred E. Heggestad
*/
#include <re.h>
#include <rem.h>
#include <baresip.h>
#include <libavcodec/avcodec.h>
#include "h26x.h"
#include "avcodec.h"
int h263_hdr_encode(const struct h263_hdr *hdr, struct mbuf *mb)
{
uint32_t v; /* host byte order */
v = hdr->f<<31 | hdr->p<<30 | hdr->sbit<<27 | hdr->ebit<<24;
v |= hdr->src<<21 | hdr->i<<20 | hdr->u<<19 | hdr->s<<18 | hdr->a<<17;
v |= hdr->r<<13 | hdr->dbq<<11 | hdr->trb<<8 | hdr->tr<<0;
return mbuf_write_u32(mb, htonl(v));
}
enum h263_mode h263_hdr_mode(const struct h263_hdr *hdr)
{
if (!hdr->f) {
return H263_MODE_A;
}
else {
if (!hdr->p)
return H263_MODE_B;
else
return H263_MODE_C;
}
}
int h263_hdr_decode(struct h263_hdr *hdr, struct mbuf *mb)
{
uint32_t v;
if (!hdr)
return EINVAL;
if (mbuf_get_left(mb) < H263_HDR_SIZE_MODEA)
return EBADMSG;
v = ntohl(mbuf_read_u32(mb));
/* Common */
hdr->f = v>>31 & 0x1;
hdr->p = v>>30 & 0x1;
hdr->sbit = v>>27 & 0x7;
hdr->ebit = v>>24 & 0x7;
hdr->src = v>>21 & 0x7;
switch (h263_hdr_mode(hdr)) {
case H263_MODE_A:
hdr->i = v>>20 & 0x1;
hdr->u = v>>19 & 0x1;
hdr->s = v>>18 & 0x1;
hdr->a = v>>17 & 0x1;
hdr->r = v>>13 & 0xf;
hdr->dbq = v>>11 & 0x3;
hdr->trb = v>>8 & 0x7;
hdr->tr = v>>0 & 0xff;
break;
case H263_MODE_B:
hdr->quant = v>>16 & 0x1f;
hdr->gobn = v>>11 & 0x1f;
hdr->mba = v>>2 & 0x1ff;
if (mbuf_get_left(mb) < 4)
return EBADMSG;
v = ntohl(mbuf_read_u32(mb));
hdr->i = v>>31 & 0x1;
hdr->u = v>>30 & 0x1;
hdr->s = v>>29 & 0x1;
hdr->a = v>>28 & 0x1;
hdr->hmv1 = v>>21 & 0x7f;
hdr->vmv1 = v>>14 & 0x7f;
hdr->hmv2 = v>>7 & 0x7f;
hdr->vmv2 = v>>0 & 0x7f;
break;
case H263_MODE_C:
/* NOTE: Mode C is optional, only parts decoded */
if (mbuf_get_left(mb) < 8)
return EBADMSG;
v = ntohl(mbuf_read_u32(mb));
hdr->i = v>>31 & 0x1;
hdr->u = v>>30 & 0x1;
hdr->s = v>>29 & 0x1;
hdr->a = v>>28 & 0x1;
(void)mbuf_read_u32(mb); /* ignore */
break;
}
return 0;
}
/**
* Find PSC (Picture Start Code) in bit-stream
*
* @param p Input bit-stream
* @param size Number of bytes in bit-stream
*
* @return Pointer to PSC if found, otherwise NULL
*/
const uint8_t *h263_strm_find_psc(const uint8_t *p, uint32_t size)
{
const uint8_t *end = p + size - 1;
for (; p < end; p++) {
if (p[0] == 0x00 && p[1] == 0x00)
return p;
}
return NULL;
}
int h263_strm_decode(struct h263_strm *s, struct mbuf *mb)
{
const uint8_t *p;
if (mbuf_get_left(mb) < 6)
return EINVAL;
p = mbuf_buf(mb);
s->psc[0] = p[0];
s->psc[1] = p[1];
s->temp_ref = (p[2]<<6 & 0xc0) | (p[3]>>2 & 0x3f);
s->split_scr = p[4]>>7 & 0x1;
s->doc_camera = p[4]>>6 & 0x1;
s->pic_frz_rel = p[4]>>5 & 0x1;
s->src_fmt = p[4]>>2 & 0x7;
s->pic_type = p[4]>>1 & 0x1;
s->umv = p[4]>>0 & 0x1;
s->sac = p[5]>>7 & 0x1;
s->apm = p[5]>>6 & 0x1;
s->pb = p[5]>>5 & 0x1;
s->pquant = p[5]>>0 & 0x1f;
s->cpm = p[6]>>7 & 0x1;
s->pei = p[6]>>6 & 0x1;
return 0;
}
/**
* Copy H.263 bit-stream to H.263 RTP payload header
*
* @param hdr H.263 header to be written to
* @param s H.263 stream header
*/
void h263_hdr_copy_strm(struct h263_hdr *hdr, const struct h263_strm *s)
{
hdr->f = 0; /* Mode A */
hdr->p = 0;
hdr->sbit = 0;
hdr->ebit = 0;
hdr->src = s->src_fmt;
hdr->i = s->pic_type;
hdr->u = s->umv;
hdr->s = s->sac;
hdr->a = s->apm;
hdr->r = 0;
hdr->dbq = 0; /* No PB-frames */
hdr->trb = 0; /* No PB-frames */
hdr->tr = s->temp_ref;
}
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