FFmpeg: libavformat/flacdec.c Source File

FFmpeg

[フレーム]

libavformat

flacdec.c

Go to the documentation of this file.

1 /*

2 * Raw FLAC demuxer

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 "libavcodec/flac.h"

23 #include "avformat.h"

24 #include "flac_picture.h"

25 #include "internal.h"

26 #include "rawdec.h"

27 #include "oggdec.h"

28 #include "vorbiscomment.h"

29 #include "libavcodec/bytestream.h"

31 static int flac_read_header(AVFormatContext *s)

32 {

33 int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;

34 uint8_t header[4];

35 uint8_t *buffer=NULL;

36 AVStream *st = avformat_new_stream(s, NULL);

37 if (!st)

38 return AVERROR(ENOMEM);

39 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

40 st->codec->codec_id = AV_CODEC_ID_FLAC;

41 st->need_parsing = AVSTREAM_PARSE_FULL_RAW;

42 /* the parameters will be extracted from the compressed bitstream */

44 /* if fLaC marker is not found, assume there is no header */

45 if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {

46 avio_seek(s->pb, -4, SEEK_CUR);

47 return 0;

48 }

50 /* process metadata blocks */

51 while (!url_feof(s->pb) && !metadata_last) {

52 avio_read(s->pb, header, 4);

53 avpriv_flac_parse_block_header(header, &metadata_last, &metadata_type,

54 &metadata_size);

55 switch (metadata_type) {

56 /* allocate and read metadata block for supported types */

57 case FLAC_METADATA_TYPE_STREAMINFO:

58 case FLAC_METADATA_TYPE_CUESHEET:

59 case FLAC_METADATA_TYPE_PICTURE:

60 case FLAC_METADATA_TYPE_VORBIS_COMMENT:

61 buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);

62 if (!buffer) {

63 return AVERROR(ENOMEM);

64 }

65 if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {

66 RETURN_ERROR(AVERROR(EIO));

67 }

68 break;

69 /* skip metadata block for unsupported types */

70 default:

71 ret = avio_skip(s->pb, metadata_size);

72 if (ret < 0)

73 return ret;

74 }

76 if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {

77 FLACStreaminfo si;

78 /* STREAMINFO can only occur once */

79 if (found_streaminfo) {

80 RETURN_ERROR(AVERROR_INVALIDDATA);

81 }

82 if (metadata_size != FLAC_STREAMINFO_SIZE) {

83 RETURN_ERROR(AVERROR_INVALIDDATA);

84 }

85 found_streaminfo = 1;

86 st->codec->extradata = buffer;

87 st->codec->extradata_size = metadata_size;

88 buffer = NULL;

90 /* get codec params from STREAMINFO header */

91 avpriv_flac_parse_streaminfo(st->codec, &si, st->codec->extradata);

93 /* set time base and duration */

94 if (si.samplerate > 0) {

95 avpriv_set_pts_info(st, 64, 1, si.samplerate);

96 if (si.samples > 0)

97 st->duration = si.samples;

98 }

99 } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {

100 uint8_t isrc[13];

101 uint64_t start;

102 const uint8_t *offset;

103 int i, chapters, track, ti;

104 if (metadata_size < 431)

105 RETURN_ERROR(AVERROR_INVALIDDATA);

106 offset = buffer + 395;

107 chapters = bytestream_get_byte(&offset) - 1;

108 if (chapters <= 0)

109 RETURN_ERROR(AVERROR_INVALIDDATA);

110 for (i = 0; i < chapters; i++) {

111 if (offset + 36 - buffer > metadata_size)

112 RETURN_ERROR(AVERROR_INVALIDDATA);

113 start = bytestream_get_be64(&offset);

114 track = bytestream_get_byte(&offset);

115 bytestream_get_buffer(&offset, isrc, 12);

116 isrc[12] = 0;

117 offset += 14;

118 ti = bytestream_get_byte(&offset);

119 if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);

120 offset += ti * 12;

121 avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);

122 }

123 av_freep(&buffer);

124 } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {

125 ret = ff_flac_parse_picture(s, buffer, metadata_size);

126 av_freep(&buffer);

127 if (ret < 0) {

128 av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");

129 return ret;

130 }

131 } else {

132 /* STREAMINFO must be the first block */

133 if (!found_streaminfo) {

134 RETURN_ERROR(AVERROR_INVALIDDATA);

135 }

136 /* process supported blocks other than STREAMINFO */

137 if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {

138 if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {

139 av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");

140 }

141 }

142 av_freep(&buffer);

143 }

144 }

145

146 return 0;

147

148 fail:

149 av_free(buffer);

150 return ret;

151 }

152

153 static int flac_probe(AVProbeData *p)

154 {

155 if (p->buf_size < 4 || memcmp(p->buf, "fLaC", 4))

156 return 0;

157 return AVPROBE_SCORE_EXTENSION;

158 }

159

160 AVInputFormat ff_flac_demuxer = {

161 .name = "flac",

162 .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),

163 .read_probe = flac_probe,

164 .read_header = flac_read_header,

165 .read_packet = ff_raw_read_partial_packet,

166 .flags = AVFMT_GENERIC_INDEX,

167 .extensions = "flac",

168 .raw_codec_id = AV_CODEC_ID_FLAC,

169 };

Generated on Sat Jan 25 2014 19:51:47 for FFmpeg by doxygen 1.8.2