ffmpeg/libavformat/rtpenc_h264.c

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/*
* RTP packetization for H.264 (RFC3984)
* Copyright (c) 2008 Luca Abeni
*
* 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
*/
/**
* @file
* @brief H.264 packetization
* @author Luca Abeni <lucabe72@email.it>
*/
#include "avformat.h"
#include "avc.h"
#include "rtpenc.h"
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static const uint8_t *avc_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size)
{
int res = 0;
if (end - start < nal_length_size)
return NULL;
while (nal_length_size--)
res = (res << 8) | *start++;
if (start + res > end || res < 0 || start + res < start)
return NULL;
return start + res;
}
static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
{
RTPMuxContext *s = s1->priv_data;
av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
if (size <= s->max_payload_size) {
ff_rtp_send_data(s1, buf, size, last);
} else {
uint8_t type = buf[0] & 0x1F;
uint8_t nri = buf[0] & 0x60;
av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */
s->buf[0] |= nri;
s->buf[1] = type;
s->buf[1] |= 1 << 7;
buf += 1;
size -= 1;
while (size + 2 > s->max_payload_size) {
memcpy(&s->buf[2], buf, s->max_payload_size - 2);
ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
buf += s->max_payload_size - 2;
size -= s->max_payload_size - 2;
s->buf[1] &= ~(1 << 7);
}
s->buf[1] |= 1 << 6;
memcpy(&s->buf[2], buf, size);
ff_rtp_send_data(s1, s->buf, size + 2, last);
}
}
void ff_rtp_send_h264(AVFormatContext *s1, const uint8_t *buf1, int size)
{
const uint8_t *r, *end = buf1 + size;
RTPMuxContext *s = s1->priv_data;
s->timestamp = s->cur_timestamp;
if (s->nal_length_size)
r = avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
else
r = ff_avc_find_startcode(buf1, end);
while (r < end) {
const uint8_t *r1;
if (s->nal_length_size) {
r1 = avc_mp4_find_startcode(r, end, s->nal_length_size);
if (!r1)
r1 = end;
r += s->nal_length_size;
} else {
while (!*(r++));
r1 = ff_avc_find_startcode(r, end);
}
nal_send(s1, r, r1 - r, r1 == end);
r = r1;
}
}