FFmpeg: libavformat/riffdec.c Source File

FFmpeg

[フレーム]

libavformat

riffdec.c

Go to the documentation of this file.

1 /*

2 * RIFF demuxing functions and data

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 "libavutil/dict.h"

23 #include "libavutil/error.h"

24 #include "libavutil/log.h"

25 #include "libavutil/mathematics.h"

26 #include "libavcodec/avcodec.h"

27 #include "libavcodec/bytestream.h"

28 #include "avformat.h"

29 #include "avio_internal.h"

30 #include "riff.h"

32 int ff_get_guid(AVIOContext *s, ff_asf_guid *g)

33 {

34 av_assert0(sizeof(*g) == 16); //compiler will optimize this out

35 if (avio_read(s, *g, sizeof(*g)) < (int)sizeof(*g)) {

36 memset(*g, 0, sizeof(*g));

37 return AVERROR_INVALIDDATA;

38 }

39 return 0;

40 }

42 enum AVCodecID ff_codec_guid_get_id(const AVCodecGuid *guids, ff_asf_guid guid)

43 {

44 int i;

45 for (i = 0; guids[i].id != AV_CODEC_ID_NONE; i++)

46 if (!ff_guidcmp(guids[i].guid, guid))

47 return guids[i].id;

48 return AV_CODEC_ID_NONE;

49 }

51 /* We could be given one of the three possible structures here:

52 * WAVEFORMAT, PCMWAVEFORMAT or WAVEFORMATEX. Each structure

53 * is an expansion of the previous one with the fields added

54 * at the bottom. PCMWAVEFORMAT adds 'WORD wBitsPerSample' and

55 * WAVEFORMATEX adds 'WORD cbSize' and basically makes itself

56 * an openended structure.

57 */

59 static void parse_waveformatex(AVIOContext *pb, AVCodecContext *c)

60 {

61 ff_asf_guid subformat;

62 int bps = avio_rl16(pb);

63 if (bps)

64 c->bits_per_coded_sample = bps;

66 c->channel_layout = avio_rl32(pb); /* dwChannelMask */

68 ff_get_guid(pb, &subformat);

69 if (!memcmp(subformat + 4,

70 (const uint8_t[]){ FF_MEDIASUBTYPE_BASE_GUID }, 12)) {

71 c->codec_tag = AV_RL32(subformat);

72 c->codec_id = ff_wav_codec_get_id(c->codec_tag,

73 c->bits_per_coded_sample);

74 } else {

75 c->codec_id = ff_codec_guid_get_id(ff_codec_wav_guids, subformat);

76 if (!c->codec_id)

77 av_log(c, AV_LOG_WARNING,

78 "unknown subformat:"FF_PRI_GUID "\n",

79 FF_ARG_GUID(subformat));

80 }

81 }

83 /* "big_endian" values are needed for RIFX file format */

84 int ff_get_wav_header(AVIOContext *pb, AVCodecContext *codec, int size, int big_endian)

85 {

86 int id;

88 if (size < 14)

89 avpriv_request_sample(codec, "wav header size < 14");

91 codec->codec_type = AVMEDIA_TYPE_AUDIO;

92 if (!big_endian) {

93 id = avio_rl16(pb);

94 codec->channels = avio_rl16(pb);

95 codec->sample_rate = avio_rl32(pb);

96 codec->bit_rate = avio_rl32(pb) * 8;

97 codec->block_align = avio_rl16(pb);

98 } else {

99 id = avio_rb16(pb);

100 codec->channels = avio_rb16(pb);

101 codec->sample_rate = avio_rb32(pb);

102 codec->bit_rate = avio_rb32(pb) * 8;

103 codec->block_align = avio_rb16(pb);

104 }

105 if (size == 14) { /* We're dealing with plain vanilla WAVEFORMAT */

106 codec->bits_per_coded_sample = 8;

107 } else {

108 if (!big_endian) {

109 codec->bits_per_coded_sample = avio_rl16(pb);

110 } else {

111 codec->bits_per_coded_sample = avio_rb16(pb);

112 }

113 }

114 if (id == 0xFFFE) {

115 codec->codec_tag = 0;

116 } else {

117 codec->codec_tag = id;

118 codec->codec_id = ff_wav_codec_get_id(id,

119 codec->bits_per_coded_sample);

120 }

121 if (size >= 18) { /* We're obviously dealing with WAVEFORMATEX */

122 int cbSize = avio_rl16(pb); /* cbSize */

123 if (big_endian) {

124 avpriv_report_missing_feature(codec, "WAVEFORMATEX support for RIFX files\n");

125 return AVERROR_PATCHWELCOME;

126 }

127 size -= 18;

128 cbSize = FFMIN(size, cbSize);

129 if (cbSize >= 22 && id == 0xfffe) { /* WAVEFORMATEXTENSIBLE */

130 parse_waveformatex(pb, codec);

131 cbSize -= 22;

132 size -= 22;

133 }

134 if (cbSize > 0) {

135 av_freep(&codec->extradata);

136 if (ff_get_extradata(codec, pb, cbSize) < 0)

137 return AVERROR(ENOMEM);

138 size -= cbSize;

139 }

140

141 /* It is possible for the chunk to contain garbage at the end */

142 if (size > 0)

143 avio_skip(pb, size);

144 }

145 if (codec->sample_rate <= 0) {

146 av_log(NULL, AV_LOG_ERROR,

147 "Invalid sample rate: %d\n", codec->sample_rate);

148 return AVERROR_INVALIDDATA;

149 }

150 if (codec->codec_id == AV_CODEC_ID_AAC_LATM) {

151 /* Channels and sample_rate values are those prior to applying SBR

152 * and/or PS. */

153 codec->channels = 0;

154 codec->sample_rate = 0;

155 }

156 /* override bits_per_coded_sample for G.726 */

157 if (codec->codec_id == AV_CODEC_ID_ADPCM_G726 && codec->sample_rate)

158 codec->bits_per_coded_sample = codec->bit_rate / codec->sample_rate;

159

160 return 0;

161 }

162

163 enum AVCodecID ff_wav_codec_get_id(unsigned int tag, int bps)

164 {

165 enum AVCodecID id;

166 id = ff_codec_get_id(ff_codec_wav_tags, tag);

167 if (id <= 0)

168 return id;

169

170 if (id == AV_CODEC_ID_PCM_S16LE)

171 id = ff_get_pcm_codec_id(bps, 0, 0, ~1);

172 else if (id == AV_CODEC_ID_PCM_F32LE)

173 id = ff_get_pcm_codec_id(bps, 1, 0, 0);

174

175 if (id == AV_CODEC_ID_ADPCM_IMA_WAV && bps == 8)

176 id = AV_CODEC_ID_PCM_ZORK;

177 return id;

178 }

179

180 int ff_get_bmp_header(AVIOContext *pb, AVStream *st, unsigned *esize)

181 {

182 int tag1;

183 if(esize) *esize = avio_rl32(pb);

184 else avio_rl32(pb);

185 st->codec->width = avio_rl32(pb);

186 st->codec->height = (int32_t)avio_rl32(pb);

187 avio_rl16(pb); /* planes */

188 st->codec->bits_per_coded_sample = avio_rl16(pb); /* depth */

189 tag1 = avio_rl32(pb);

190 avio_rl32(pb); /* ImageSize */

191 avio_rl32(pb); /* XPelsPerMeter */

192 avio_rl32(pb); /* YPelsPerMeter */

193 avio_rl32(pb); /* ClrUsed */

194 avio_rl32(pb); /* ClrImportant */

195 return tag1;

196 }

197

198 int ff_read_riff_info(AVFormatContext *s, int64_t size)

199 {

200 int64_t start, end, cur;

201 AVIOContext *pb = s->pb;

202

203 start = avio_tell(pb);

204 end = start + size;

205

206 while ((cur = avio_tell(pb)) >= 0 &&

207 cur <= end - 8 /* = tag + size */) {

208 uint32_t chunk_code;

209 int64_t chunk_size;

210 char key[5] = { 0 };

211 char *value;

212

213 chunk_code = avio_rl32(pb);

214 chunk_size = avio_rl32(pb);

215 if (avio_feof(pb)) {

216 if (chunk_code || chunk_size) {

217 av_log(s, AV_LOG_WARNING, "INFO subchunk truncated\n");

218 return AVERROR_INVALIDDATA;

219 }

220 return AVERROR_EOF;

221 }

222 if (chunk_size > end ||

223 end - chunk_size < cur ||

224 chunk_size == UINT_MAX) {

225 avio_seek(pb, -9, SEEK_CUR);

226 chunk_code = avio_rl32(pb);

227 chunk_size = avio_rl32(pb);

228 if (chunk_size > end || end - chunk_size < cur || chunk_size == UINT_MAX) {

229 av_log(s, AV_LOG_WARNING, "too big INFO subchunk\n");

230 return AVERROR_INVALIDDATA;

231 }

232 }

233

234 chunk_size += (chunk_size & 1);

235

236 if (!chunk_code) {

237 if (chunk_size)

238 avio_skip(pb, chunk_size);

239 else if (pb->eof_reached) {

240 av_log(s, AV_LOG_WARNING, "truncated file\n");

241 return AVERROR_EOF;

242 }

243 continue;

244 }

245

246 value = av_mallocz(chunk_size + 1);

247 if (!value) {

248 av_log(s, AV_LOG_ERROR,

249 "out of memory, unable to read INFO tag\n");

250 return AVERROR(ENOMEM);

251 }

252

253 AV_WL32(key, chunk_code);

254

255 if (avio_read(pb, value, chunk_size) != chunk_size) {

256 av_log(s, AV_LOG_WARNING,

257 "premature end of file while reading INFO tag\n");

258 }

259

260 av_dict_set(&s->metadata, key, value, AV_DICT_DONT_STRDUP_VAL);

261 }

262

263 return 0;

264 }

Generated on Sun Mar 8 2015 02:35:11 for FFmpeg by doxygen 1.8.2