ffmpeg/libavformat/rtpenc_amr.c

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/*
* RTP packetization for AMR audio
* Copyright (c) 2007 Luca Abeni
* Copyright (c) 2009 Martin Storsjo
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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"
/**
* Packetize AMR frames into RTP packets according to RFC 3267,
* in octet-aligned mode.
*/
void ff_rtp_send_amr(AVFormatContext *s1, const uint8_t *buff, int size)
{
RTPMuxContext *s = s1->priv_data;
AVStream *st = s1->streams[0];
int max_header_toc_size = 1 + s->max_frames_per_packet;
uint8_t *p;
int len;
/* Test if the packet must be sent. */
len = s->buf_ptr - s->buf;
if (s->num_frames &&
(s->num_frames == s->max_frames_per_packet ||
len + size - 1 > s->max_payload_size ||
av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,
s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
int header_size = s->num_frames + 1;
p = s->buf + max_header_toc_size - header_size;
if (p != s->buf)
memmove(p, s->buf, header_size);
ff_rtp_send_data(s1, p, s->buf_ptr - p, 1);
s->num_frames = 0;
}
if (!s->num_frames) {
s->buf[0] = 0xf0;
s->buf_ptr = s->buf + max_header_toc_size;
s->timestamp = s->cur_timestamp;
} else {
/* Mark the previous TOC entry as having more entries following. */
s->buf[1 + s->num_frames - 1] |= 0x80;
}
/* Copy the frame type and quality bits. */
s->buf[1 + s->num_frames++] = buff[0] & 0x7C;
buff++;
size--;
memcpy(s->buf_ptr, buff, size);
s->buf_ptr += size;
}