1 /*
2 * RTP packetization for AMR audio
3 * Copyright (c) 2007 Luca Abeni
4 * Copyright (c) 2009 Martin Storsjo
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
25
26 /**
27 * Packetize AMR frames into RTP packets according to RFC 3267,
28 * in octet-aligned mode.
29 */
31 {
34 int max_header_toc_size = 1 +
s->max_frames_per_packet;
37
38 /* Test if the packet must be sent. */
39 len =
s->buf_ptr -
s->buf;
41 (
s->num_frames ==
s->max_frames_per_packet ||
42 len +
size - 1 >
s->max_payload_size ||
45 int header_size =
s->num_frames + 1;
46 p =
s->buf + max_header_toc_size - header_size;
48 memmove(
p,
s->buf, header_size);
49
51
53 }
54
57 s->buf_ptr =
s->buf + max_header_toc_size;
58 s->timestamp =
s->cur_timestamp;
59 } else {
60 /* Mark the previous TOC entry as having more entries following. */
61 s->buf[1 +
s->num_frames - 1] |= 0x80;
62 }
63
64 /* Copy the frame type and quality bits. */
65 s->buf[1 +
s->num_frames++] = buff[0] & 0x7C;
66 buff++;
68 memcpy(
s->buf_ptr, buff,
size);
70 }