static int dec_h263(struct vidcodec_st *st, struct vidframe *frame,
bool eof, struct mbuf *src)
{
struct h263_hdr h263_hdr;
int err;
if (!src)
return 0;
err = h263_hdr_decode(&h263_hdr, src);
if (err)
return err;
if (!st->got_keyframe && h263_hdr.i == I_FRAME)
st->got_keyframe = true;
return ffdecode(st, frame, eof, src);
}
int decode_h263(struct viddec_state *st, struct vidframe *frame,
bool marker, uint16_t seq, struct mbuf *src)
{
struct h263_hdr hdr;
int err;
if (!st || !frame)
return EINVAL;
if (!src)
return 0;
(void)seq;
err = h263_hdr_decode(&hdr, src);
if (err)
return err;
#if 0
debug(".....[%s seq=%5u ] MODE %s -"
" SBIT=%u EBIT=%u I=%s"
" (%5u/%5u bytes)\n",
marker ? "M" : " ", seq,
h263_hdr_mode(&hdr) == H263_MODE_A ? "A" : "B",
hdr.sbit, hdr.ebit, hdr.i ? "Inter" : "Intra",
mbuf_get_left(src), st->mb->end);
#endif
if (!hdr.i)
st->got_keyframe = true;
#if 0
if (st->mb->pos == 0) {
uint8_t *p = mbuf_buf(src);
if (p[0] != 0x00 || p[1] != 0x00) {
warning("invalid PSC detected (%02x %02x)\n",
p[0], p[1]);
return EPROTO;
}
}
#endif
/*
* The H.263 Bit-stream can be fragmented on bit-level,
* indicated by SBIT and EBIT. Example:
*
* 8 bit 2 bit
* .--------.--.
* Packet 1 | | |
* SBIT=0 '--------'--'
* EBIT=6
* .------.--------.--------.
* Packet 2 | | | |
* SBIT=2 '------'--------'--------'
* EBIT=0 6bit 8bit 8bit
*
*/
if (hdr.sbit > 0) {
const uint8_t mask = (1 << (8 - hdr.sbit)) - 1;
const uint8_t sbyte = mbuf_read_u8(src) & mask;
st->mb->buf[st->mb->end - 1] |= sbyte;
}
return ffdecode(st, frame, marker, src);
}