PeerStreamer

/*

 * RTP packetization for AMR audio

 * Copyright (c) 2007 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"

/**

 * 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;

    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->max_frames_per_packet || (len && len + size - 1 > s->max_payload_size)) {

        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;

}