| 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 | |
| 23 | #include "avformat.h" |
| 24 | #include "rtpenc.h" |
| 25 | |
| 26 | /** |
| 27 | * Packetize AMR frames into RTP packets according to RFC 3267, |
| 28 | * in octet-aligned mode. |
| 29 | */ |
| 30 | void ff_rtp_send_amr(AVFormatContext *s1, const uint8_t *buff, int size) |
| 31 | { |
| 32 | RTPMuxContext *s = s1->priv_data; |
| 33 | int max_header_toc_size = 1 + s->max_frames_per_packet; |
| 34 | uint8_t *p; |
| 35 | int len; |
| 36 | |
| 37 | /* Test if the packet must be sent. */ |
| 38 | len = s->buf_ptr - s->buf; |
| 39 | if (s->num_frames == s->max_frames_per_packet || (len && len + size - 1 > s->max_payload_size)) { |
| 40 | int header_size = s->num_frames + 1; |
| 41 | p = s->buf + max_header_toc_size - header_size; |
| 42 | if (p != s->buf) |
| 43 | memmove(p, s->buf, header_size); |
| 44 | |
| 45 | ff_rtp_send_data(s1, p, s->buf_ptr - p, 1); |
| 46 | |
| 47 | s->num_frames = 0; |
| 48 | } |
| 49 | |
| 50 | if (!s->num_frames) { |
| 51 | s->buf[0] = 0xf0; |
| 52 | s->buf_ptr = s->buf + max_header_toc_size; |
| 53 | s->timestamp = s->cur_timestamp; |
| 54 | } else { |
| 55 | /* Mark the previous TOC entry as having more entries following. */ |
| 56 | s->buf[1 + s->num_frames - 1] |= 0x80; |
| 57 | } |
| 58 | |
| 59 | /* Copy the frame type and quality bits. */ |
| 60 | s->buf[1 + s->num_frames++] = buff[0] & 0x7C; |
| 61 | buff++; |
| 62 | size--; |
| 63 | memcpy(s->buf_ptr, buff, size); |
| 64 | s->buf_ptr += size; |
| 65 | } |