ffmpeg/libavformat/rtp_mpv.c

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/*
* RTP packetization for MPEG video
* Copyright (c) 2002 Fabrice Bellard.
* Copyright (c) 2007 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
*/
#include "libavcodec/mpegvideo.h"
#include "avformat.h"
#include "rtp_internal.h"
/* NOTE: a single frame must be passed with sequence header if
needed. XXX: use slices. */
void ff_rtp_send_mpegvideo(AVFormatContext *s1, const uint8_t *buf1, int size)
{
RTPDemuxContext *s = s1->priv_data;
int len, h, max_packet_size;
uint8_t *q;
int begin_of_slice, end_of_slice, frame_type, temporal_reference;
max_packet_size = s->max_payload_size;
begin_of_slice = 1;
end_of_slice = 0;
frame_type = 0;
temporal_reference = 0;
while (size > 0) {
int begin_of_sequence;
begin_of_sequence = 0;
len = max_packet_size - 4;
if (len >= size) {
len = size;
end_of_slice = 1;
} else {
const uint8_t *r, *r1;
int start_code;
r1 = buf1;
while (1) {
start_code = -1;
r = ff_find_start_code(r1, buf1 + size, &start_code);
if((start_code & 0xFFFFFF00) == 0x100) {
/* New start code found */
if (start_code == 0x100) {
frame_type = (r[1] & 0x38) >> 3;
temporal_reference = (int)r[0] << 2 | r[1] >> 6;
}
if (start_code == 0x1B8) {
begin_of_sequence = 1;
}
if (r - buf1 - 4 <= len) {
/* The current slice fits in the packet */
if (begin_of_slice == 0) {
/* no slice at the beginning of the packet... */
end_of_slice = 1;
len = r - buf1 - 4;
break;
}
r1 = r;
} else {
if ((r1 - buf1 > 4) && (r - r1 < max_packet_size)) {
len = r1 - buf1 - 4;
end_of_slice = 1;
}
break;
}
} else {
break;
}
}
}
h = 0;
h |= temporal_reference << 16;
h |= begin_of_sequence << 13;
h |= begin_of_slice << 12;
h |= end_of_slice << 11;
h |= frame_type << 8;
q = s->buf;
*q++ = h >> 24;
*q++ = h >> 16;
*q++ = h >> 8;
*q++ = h;
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;
begin_of_slice = end_of_slice;
end_of_slice = 0;
}
}