FFmpeg: libavformat/rtpenc_h264.c Source File

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libavformat

rtpenc_h264.c

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1 /*

2 * RTP packetization for H.264 (RFC3984)

4 *

5 * This file is part of FFmpeg.

6 *

7 * FFmpeg is free software; you can redistribute it and/or

8 * modify it under the terms of the GNU Lesser General Public

9 * License as published by the Free Software Foundation; either

10 * version 2.1 of the License, or (at your option) any later version.

11 *

12 * FFmpeg is distributed in the hope that it will be useful,

13 * but WITHOUT ANY WARRANTY; without even the implied warranty of

14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

15 * Lesser General Public License for more details.

16 *

17 * You should have received a copy of the GNU Lesser General Public

18 * License along with FFmpeg; if not, write to the Free Software

19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

20 */

22 /**

23 * @file

24 * @brief H.264 packetization

25 * @author Luca Abeni <lucabe72@email.it>

26 */

28 #include "avformat.h"

29 #include "avc.h"

30 #include "rtpenc.h"

32 static const uint8_t *avc_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size)

33 {

34 unsigned int res = 0;

36 if (end - start < nal_length_size)

37 return NULL;

38 while (nal_length_size--)

39 res = (res << 8) | *start++;

41 if (res > end - start)

42 return NULL;

44 return start + res;

45 }

47 static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)

48 {

49 RTPMuxContext *s = s1->priv_data;

51 av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);

52 if (size <= s->max_payload_size) {

53 ff_rtp_send_data(s1, buf, size, last);

54 } else {

55 uint8_t type = buf[0] & 0x1F;

56 uint8_t nri = buf[0] & 0x60;

58 if (s->flags & FF_RTP_FLAG_H264_MODE0) {

59 av_log(s1, AV_LOG_ERROR,

60 "NAL size %d > %d, try -slice-max-size %d\n", size,

61 s->max_payload_size, s->max_payload_size);

62 return;

63 }

64 av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);

65 s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */

66 s->buf[0] |= nri;

67 s->buf[1] = type;

68 s->buf[1] |= 1 << 7;

69 buf += 1;

70 size -= 1;

71 while (size + 2 > s->max_payload_size) {

72 memcpy(&s->buf[2], buf, s->max_payload_size - 2);

73 ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);

74 buf += s->max_payload_size - 2;

75 size -= s->max_payload_size - 2;

76 s->buf[1] &= ~(1 << 7);

77 }

78 s->buf[1] |= 1 << 6;

79 memcpy(&s->buf[2], buf, size);

80 ff_rtp_send_data(s1, s->buf, size + 2, last);

81 }

82 }

84 void ff_rtp_send_h264(AVFormatContext *s1, const uint8_t *buf1, int size)

85 {

86 const uint8_t *r, *end = buf1 + size;

87 RTPMuxContext *s = s1->priv_data;

89 s->timestamp = s->cur_timestamp;

90 if (s->nal_length_size)

91 r = avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;

92 else

93 r = ff_avc_find_startcode(buf1, end);

94 while (r < end) {

95 const uint8_t *r1;

97 if (s->nal_length_size) {

98 r1 = avc_mp4_find_startcode(r, end, s->nal_length_size);

99 if (!r1)

100 r1 = end;

101 r += s->nal_length_size;

102 } else {

103 while (!*(r++));

104 r1 = ff_avc_find_startcode(r, end);

105 }

106 nal_send(s1, r, r1 - r, r1 == end);

107 r = r1;

108 }

109 }

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