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/*
* RTP packetization for H.263 video
* Copyright (c) 2009 Luca Abeni
* Copyright (c) 2009 Martin Storsjo
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "rtpenc.h"
static const uint8_t *find_resync_marker_reverse(const uint8_t *restrict start,
const uint8_t *restrict end)
{
const uint8_t *p = end - 1;
start += 1; /* Make sure we never return the original start. */
for (; p > start; p -= 2) {
if (!*p) {
if (!p[ 1] && p[2]) return p;
else if (!p[-1] && p[1]) return p - 1;
}
}
return end;
}
/**
* Packetize H.263 frames into RTP packets according to RFC 4629
*/
void ff_rtp_send_h263(AVFormatContext *s1, const uint8_t *buf1, int size)
{
RTPMuxContext *s = s1->priv_data;
int len, max_packet_size;
uint8_t *q;
max_packet_size = s->max_payload_size;
while (size > 0) {
q = s->buf;
if (size >= 2 && (buf1[0] == 0) && (buf1[1] == 0)) {
*q++ = 0x04;
buf1 += 2;
size -= 2;
} else {
*q++ = 0;
}
*q++ = 0;
len = FFMIN(max_packet_size - 2, size);
/* Look for a better place to split the frame into packets. */
if (len < size) {
const uint8_t *end = find_resync_marker_reverse(buf1, buf1 + len);
len = end - buf1;
}
memcpy(q, buf1, len);
q += len;
/* 90 KHz time stamp */
s->timestamp = s->cur_timestamp;
ff_rtp_send_data(s1, s->buf, q - s->buf, (len == size));
buf1 += len;
size -= len;
}
}
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