FFmpeg: libavformat/ilbc.c Source File

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libavformat

ilbc.c

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1 /*

2 * iLBC storage file format

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 #include "avformat.h"

23 #include "internal.h"

25 static const char mode20_header[] = "#!iLBC20\n";

26 static const char mode30_header[] = "#!iLBC30\n";

28 static int ilbc_write_header(AVFormatContext *s)

29 {

30 AVIOContext *pb = s->pb;

31 AVCodecContext *enc;

33 if (s->nb_streams != 1) {

34 av_log(s, AV_LOG_ERROR, "Unsupported number of streams\n");

35 return AVERROR(EINVAL);

36 }

37 enc = s->streams[0]->codec;

39 if (enc->codec_id != AV_CODEC_ID_ILBC) {

40 av_log(s, AV_LOG_ERROR, "Unsupported codec\n");

41 return AVERROR(EINVAL);

42 }

44 if (enc->block_align == 50) {

45 avio_write(pb, mode30_header, sizeof(mode30_header) - 1);

46 } else if (enc->block_align == 38) {

47 avio_write(pb, mode20_header, sizeof(mode20_header) - 1);

48 } else {

49 av_log(s, AV_LOG_ERROR, "Unsupported mode\n");

50 return AVERROR(EINVAL);

51 }

52 avio_flush(pb);

53 return 0;

54 }

56 static int ilbc_write_packet(AVFormatContext *s, AVPacket *pkt)

57 {

58 avio_write(s->pb, pkt->data, pkt->size);

59 return 0;

60 }

62 static int ilbc_probe(AVProbeData *p)

63 {

64 // Only check for "#!iLBC" which matches both formats

65 if (!memcmp(p->buf, mode20_header, 6))

66 return AVPROBE_SCORE_MAX;

67 else

68 return 0;

69 }

71 static int ilbc_read_header(AVFormatContext *s)

72 {

73 AVIOContext *pb = s->pb;

74 AVStream *st;

75 uint8_t header[9];

77 avio_read(pb, header, 9);

79 st = avformat_new_stream(s, NULL);

80 if (!st)

81 return AVERROR(ENOMEM);

82 st->codec->codec_id = AV_CODEC_ID_ILBC;

83 st->codec->sample_rate = 8000;

84 st->codec->channels = 1;

85 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

86 st->start_time = 0;

87 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

88 if (!memcmp(header, mode20_header, sizeof(mode20_header) - 1)) {

89 st->codec->block_align = 38;

90 st->codec->bit_rate = 15200;

91 } else if (!memcmp(header, mode30_header, sizeof(mode30_header) - 1)) {

92 st->codec->block_align = 50;

93 st->codec->bit_rate = 13333;

94 } else {

95 av_log(s, AV_LOG_ERROR, "Unrecognized iLBC file header\n");

96 return AVERROR_INVALIDDATA;

97 }

99 return 0;

100 }

101

102 static int ilbc_read_packet(AVFormatContext *s,

103 AVPacket *pkt)

104 {

105 AVCodecContext *enc = s->streams[0]->codec;

106 int ret;

107

108 if ((ret = av_new_packet(pkt, enc->block_align)) < 0)

109 return ret;

110

111 pkt->stream_index = 0;

112 pkt->pos = avio_tell(s->pb);

113 pkt->duration = enc->block_align == 38 ? 160 : 240;

114 if ((ret = avio_read(s->pb, pkt->data, enc->block_align)) != enc->block_align) {

115 av_free_packet(pkt);

116 return ret < 0 ? ret : AVERROR(EIO);

117 }

118

119 return 0;

120 }

121

122 AVInputFormat ff_ilbc_demuxer = {

123 .name = "ilbc",

124 .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),

125 .read_probe = ilbc_probe,

126 .read_header = ilbc_read_header,

127 .read_packet = ilbc_read_packet,

128 .flags = AVFMT_GENERIC_INDEX,

129 };

130

131 AVOutputFormat ff_ilbc_muxer = {

132 .name = "ilbc",

133 .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),

134 .mime_type = "audio/iLBC",

135 .extensions = "lbc",

136 .audio_codec = AV_CODEC_ID_ILBC,

137 .write_header = ilbc_write_header,

138 .write_packet = ilbc_write_packet,

139 .flags = AVFMT_NOTIMESTAMPS,

140 };

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