FFmpeg: libavformat/rtpenc_amr.c Source File

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libavformat

rtpenc_amr.c

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1 /*

2 * RTP packetization for AMR audio

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 */

23 #include "avformat.h"

24 #include "rtpenc.h"

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 AVStream *st = s1->streams[0];

34 int max_header_toc_size = 1 + s->max_frames_per_packet;

35 uint8_t *p;

36 int len;

38 /* Test if the packet must be sent. */

39 len = s->buf_ptr - s->buf;

40 if (s->num_frames &&

41 (s->num_frames == s->max_frames_per_packet ||

42 len + size - 1 > s->max_payload_size ||

43 av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,

44 s1->max_delay, AV_TIME_BASE_Q) >= 0)) {

45 int header_size = s->num_frames + 1;

46 p = s->buf + max_header_toc_size - header_size;

47 if (p != s->buf)

48 memmove(p, s->buf, header_size);

50 ff_rtp_send_data(s1, p, s->buf_ptr - p, 1);

52 s->num_frames = 0;

53 }

55 if (!s->num_frames) {

56 s->buf[0] = 0xf0;

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 }

64 /* Copy the frame type and quality bits. */

65 s->buf[1 + s->num_frames++] = buff[0] & 0x7C;

66 buff++;

67 size--;

68 memcpy(s->buf_ptr, buff, size);

69 s->buf_ptr += size;

70 }

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