1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 2 <html> 3 <head> 4 <link rel="stylesheet" type="text/css" href="opus_in_isobmff.css"/> 5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6 <title>Encapsulation of Opus in ISO Base Media File Format</title> 7 </head> 8 <body bgcolor="0x333333" text="#60B0C0"> 9 <b><u>Encapsulation of Opus in ISO Base Media File Format</u></b><br> 10 <font size="2">last updated: August 28, 2018</font><br> 11 <br> 12 <div class="normal_link pre frame_box"> 13 14 Encapsulation of Opus in ISO Base Media File Format 15 Version 0.8.1 (incomplete) 16 17 18 Table of Contents 19 <a href="#1">1</a> Scope 20 <a href="#2">2</a> Normative References 21 <a href="#3">3</a> Terms and Definitions 22 <a href="#4">4</a> Design Rules of Encapsulation 23 <a href="#4.1">4.1</a> File Type Identification 24 <a href="#4.2">4.2</a> Overview of Track Structure 25 <a href="#4.3">4.3</a> Definitions of Opus sample 26 <a href="#4.3.1">4.3.1</a> Sample entry format 27 <a href="#4.3.2">4.3.2</a> Opus Specific Box 28 <a href="#4.3.3">4.3.3</a> Sample format 29 <a href="#4.3.4">4.3.4</a> Duration of Opus sample 30 <a href="#4.3.5">4.3.5</a> Sub-sample 31 <a href="#4.3.6">4.3.6</a> Random Access 32 <a href="#4.3.6.1">4.3.6.1</a> Random Access Point 33 <a href="#4.3.6.2">4.3.6.2</a> Pre-roll 34 <a href="#4.4">4.4</a> Trimming of Actual Duration 35 <a href="#4.5">4.5</a> Channel Mapping 36 <a href="#4.5.1">4.5.1</a> ISO Base Media native Channel Mapping 37 <a href="#4.5.2">4.5.2</a> Composition on all active tracks (informative) 38 <a href="#4.6">4.6</a> Basic Structure (informative) 39 <a href="#4.6.1">4.6.2</a> Initial Movie 40 <a href="#4.6.2">4.6.3</a> Movie Fragments 41 <a href="#4.7">4.7</a> Example of Encapsulation (informative) 42 <a href="#5">5</a> Author's Address 43 44 <a name="1"></a> 45 1 Scope 46 This specification specifies the fundamental way of the encapsulation of Opus coded bitstreams in ISO Base Media 47 file format and its derivatives. The encapsulation of Opus coded bitstreams in QuickTime file format is outside 48 the scope of this specification. 49 50 <a name="2"></a> 51 2 Normative References 52 [1] ISO/IEC 14496-12:2015 Corrected version 53 Information technology Coding of audio-visual objects Part 12: ISO base media file format 54 55 [2] RFC 6716 56 Definition of the Opus Audio Codec 57 58 [3] RFC 7845 59 Ogg Encapsulation for the Opus Audio Codec 60 61 <a name="3"></a> 62 3 Terms and Definitions 63 3.1 active track 64 enabled track from the non-alternate group or selected track from alternate group 65 66 3.2 actual duration 67 duration constructed from valid samples 68 69 3.3 edit 70 entry in the Edit List Box 71 72 3.4 padded samples 73 PCM samples after decoding Opus sample(s) which are not valid samples 74 An Opus bitstream always contains them partially at the beginning and may contain them in part at the end, as 75 long as not physically removed yet at the beginning and/or the end. 76 77 3.5 priming samples 78 padded samples at the beginning of the Opus bitstream 79 80 3.6 sample-accurate 81 for any PCM sample, a timestamp exactly matching its sampling timestamp is present in the media timeline. 82 83 3.7 valid samples 84 PCM samples after decoding Opus sample(s) corresponding to input PCM samples 85 86 <a name="4"></a> 87 4 Design Rules of Encapsulation 88 4.1 File Type Identification<a name="4.1"></a> 89 This specification defines the brand 'Opus' to declare files are conformant to this specification. Additionally, 90 files conformant to this specification shall contain at least one brand, which supports the requirements and the 91 requirements described in this clause without contradiction, in the compatible brands list of the File Type Box. 92 As an example, the minimal support of the encapsulation of Opus bitstreams in ISO Base Media file format requires 93 the 'iso2' brand in the compatible brands list since support of roll groups is required. 94 <a name="4.2"></a> 95 4.2 Overview of Track Structure 96 This clause summarizes requirements of the encapsulation of Opus coded bitstream as media data in audio tracks 97 in file formats compliant with the ISO Base Media File Format. The details are described in clauses after this 98 clause. 99 + The handler_type field in the Handler Reference Box shall be set to 'soun'. 100 + The Media Information Box shall contain the Sound Media Header Box. 101 + The codingname of the sample entry is 'Opus'. 102 This specification does not define any encapsulation using MP4AudioSampleEntry with objectTypeIndication 103 specified by the MPEG-4 Registration Authority (http://www.mp4ra.org/). 104 See 4.3.1 Sample entry format to get the details about the sample entry. 105 + The 'dOps' box is added to the sample entry to convey initializing information for the decoder. 106 See 4.3.2 Opus Specific Box to get the details. 107 + An Opus sample is exactly one Opus packet for each of different Opus bitstreams. 108 See 4.3.3 Sample format to get the details. 109 + Every Opus sample is a sync sample but requires pre-roll for every random access to get correct output. 110 See 4.3.6 Random Access to get the details. 111 <a name="4.3"></a> 112 4.3 Definitions of Opus sample 113 4.3.1 Sample entry format<a name="4.3.1"></a> 114 For any track containing Opus bitstreams, at least one sample entry describing corresponding Opus bitstream 115 shall be present inside the Sample Table Box. This version of the specification defines only one sample 116 entry format named OpusSampleEntry whose codingname is 'Opus'. This sample entry includes exactly one Opus 117 Specific Box defined in 4.3.2 as a mandatory box and indicates that Opus samples described by this sample 118 entry are stored by the sample format described in 4.3.3. 119 120 The syntax and semantics of the OpusSampleEntry is shown as follows. 121 122 class OpusSampleEntry() extends AudioSampleEntry ('Opus') { 123 OpusSpecificBox(); 124 } 125 126 + channelcount: 127 The channelcount field indicates the number of output channels and shall be set to the same value of 128 the OutputChannelCount in the OpusDecoderConfigurationRecord. The value of this field may be used in 129 the ChannelLayout if any as described in 4.5.1. 130 + samplesize: 131 The samplesize field shall be set to 16. 132 + samplerate: 133 The samplerate field shall be set to 48000<<16. 134 + OpusSpecificBox 135 This box contains initializing information for the decoder as defined in 4.3.2. 136 137 4.3.2 Opus Specific Box<a name="4.3.2"></a> 138 Exactly one Opus Specific Box shall be present in each OpusSampleEntry. 139 The Opus Specific Box contains an OpusDecoderConfigurationRecord which contains the Version field and 140 this specification defines version 0 of this record. If incompatible changes occured in the fields after 141 the Version field within the OpusDecoderConfigurationRecord in the future versions of this specification, 142 another version will be defined. 143 This box refers to Ogg Opus [3] at many parts but all the data are stored as big-endian format. 144 145 The syntax and semantics of the Opus Specific Box is shown as follows. 146 147 class ChannelMappingTable (unsigned int(8) OutputChannelCount) { 148 unsigned int(8) StreamCount; 149 unsigned int(8) CoupledCount; 150 unsigned int(8 * OutputChannelCount) ChannelMapping; 151 } 152 153 aligned(8) class OpusDecoderConfigurationRecord { 154 unsigned int(8) Version; 155 unsigned int(8) OutputChannelCount; 156 unsigned int(16) PreSkip; 157 unsigned int(32) InputSampleRate; 158 signed int(16) OutputGain; 159 unsigned int(8) ChannelMappingFamily; 160 if (ChannelMappingFamily != 0) { 161 ChannelMappingTable(OutputChannelCount); 162 } 163 } 164 165 class OpusSpecificBox extends Box('dOps') { 166 OpusDecoderConfigurationRecord() OpusConfig; 167 } 168 169 + Version: 170 The Version field shall be set to 0. 171 In the future versions of this specification, this field may be set to other values. And without support 172 of those values, the reader shall not read the fields after this within the OpusSpecificBox. 173 + OutputChannelCount: 174 The OutputChannelCount field shall be set to the same value as the *Output Channel Count* field in the 175 identification header defined in Ogg Opus [3]. 176 + PreSkip: 177 The PreSkip field indicates the number of the priming samples, that is, the number of samples at 48000 Hz 178 to discard from the decoder output when starting playback. The value of the PreSkip field shall be at least 179 80 milliseconds' worth of PCM samples even when removing any number of Opus samples which may or may not 180 contain the priming samples. The PreSkip field is not used for discarding the priming samples at the whole 181 playback at all since it is informative only, and that task falls on the Edit List Box. 182 + InputSampleRate: 183 The InputSampleRate field shall be set to the same value as the *Input Sample Rate* field in the 184 identification header defined in Ogg Opus [3]. 185 + OutputGain: 186 The OutputGain field shall be set to the same value as the *Output Gain* field in the identification 187 header define in Ogg Opus [3]. Note that the value is stored as 8.8 fixed-point. 188 + ChannelMappingFamily: 189 The ChannelMappingFamily field shall be set to the same value as the *Channel Mapping Family* field in 190 the identification header defined in Ogg Opus [3]. Note that the value 255 may be used for an alternative 191 to map channels by ISO Base Media native mapping. The details are described in 4.5.1. 192 + StreamCount: 193 The StreamCount field shall be set to the same value as the *Stream Count* field in the identification 194 header defined in Ogg Opus [3]. 195 + CoupledCount: 196 The CoupledCount field shall be set to the same value as the *Coupled Count* field in the identification 197 header defined in Ogg Opus [3]. 198 + ChannelMapping: 199 The ChannelMapping field shall be set to the same octet string as *Channel Mapping* field in the identi- 200 fication header defined in Ogg Opus [3]. 201 202 4.3.3 Sample format<a name="4.3.3"></a> 203 An Opus sample is exactly one Opus packet for each of different Opus bitstreams. Due to support more than 204 two channels, an Opus sample can contain frames from multiple Opus bitstreams but all Opus packets shall 205 share with the total of frame sizes in a single Opus sample. The way of how to pack an Opus packet from 206 each of Opus bitstreams into a single Opus sample follows Appendix B. in RFC 6716 [2]. 207 The endianness has nothing to do with any Opus sample since every Opus packet is processed byte-by-byte. 208 In this specification, 'sample' means 'Opus sample' except for 'padded samples', 'priming samples', 'valid 209 sample' and 'sample-accurate', i.e. 'sample' is 'sample' in the term defined in ISO/IEC 14496-12 [1]. 210 211 +-----------------------------------------+-------------------------------------+ 212 | Opus packet 0 (self-delimiting framing) | Opus packet 1 (undelimited framing) | 213 +-----------------------------------------+-------------------------------------+ 214 |<---------------------------- the size of Opus sample ------------------------>| 215 216 Figure 1 - Example structure of an Opus sample containing two Opus bitstreams 217 218 4.3.4 Duration of Opus sample<a name="4.3.4"></a> 219 The duration of Opus sample is given by multiplying the total of frame sizes for a single Opus bitstream 220 expressed in seconds by the value of the timescale field in the Media Header Box. 221 Let's say an Opus sample consists of two Opus bitstreams, where the frame size of one bitstream is 40 milli- 222 seconds and the frame size of another is 60 milliseconds, and the timescale field in the Media Header Box 223 is set to 48000, then the duration of that Opus sample shall be 120 milliseconds since three 40 millisecond 224 frame and two 60 millisecond frames shall be contained because of the maximum duration of Opus packet, 120 225 milliseconds, and 5760 in the timescale indicated in the Media Header Box. 226 227 To indicate the valid samples excluding the padded samples at the end of Opus bitstream, the duration of 228 the last Opus sample of an Opus bitstream is given by multiplying the number of the valid samples by the 229 value produced by dividing the value of the timescale field in the Media Header Box by 48000. 230 231 4.3.5 Sub-sample<a name="4.3.5"></a> 232 The structure of the last Opus packet in an Opus sample is different from the others in the same Opus sample, 233 and the others are invalid Opus packets as an Opus sample because of self-delimiting framing. To avoid 234 complexities, sub-sample is not defined for Opus sample in this specification. 235 236 4.3.6 Random Access<a name="4.3.6"></a> 237 This subclause describes the nature of the random access of Opus sample. 238 239 4.3.6.1 Random Access Point<a name="4.3.6.1"></a> 240 All Opus samples can be independently decoded i.e. every Opus sample is a sync sample. Therefore, the 241 Sync Sample Box shall not be present as long as there are no samples other than Opus samples in the same 242 track. And the sample_is_non_sync_sample field for Opus samples shall be set to 0. 243 244 4.3.6.2 Pre-roll<a name="4.3.6.2"></a> 245 Opus bitstream requires at least 80 millisecond pre-roll after each random access to get correct output. 246 Pre-roll is indicated by the roll_distance field in AudioRollRecoveryEntry. AudioPreRollEntry shall not 247 be used since every Opus sample is a sync sample in Opus bitstream. Note that roll_distance is expressed 248 in sample units in a term of ISO Base Media File Format, and always takes negative values. 249 250 For any track containing Opus bitstreams, at least one Sample Group Description Box and at least one 251 Sample to Group Box within the Sample Table Box shall be present and these have the grouping_type field 252 set to 'roll'. If any Opus sample is contained in a track fragment, the Sample to Group Box with the 253 grouping_type field set to 'roll' shall be present for that track fragment. 254 255 For the requirement of AudioRollRecoveryEntry, the compatible_brands field in the File Type Box shall 256 contain at least one brand which requires support for roll groups. 257 <a name="4.4"></a> 258 4.4 Trimming of Actual Duration 259 Due to the priming samples (or the padding at the beginning) derived from the pre-roll for the startup and the 260 padded samples at the end, we need trim from media to get the actual duration. An edit in the Edit List Box can 261 achieve this demand, and the Edit Box and the Edit List Box shall be present. 262 263 For sample-accurate trimming, proper timescale should be set to the timescale field in the Movie Header Box 264 and the Media Header Box inside Track Box(es) for Opus bitstream. The timescale field in the Media Header Box is 265 typically set to 48000. It is recommended that the timescale field in the Movie Header Box be set to the same 266 value of the timescale field in the Media Header Box in order to avoid the rounding problem when specifying 267 duration of edit if the timescales in all of the Media Header Boxes are set to the same value. 268 269 For example, to indicate the actual duration of an Opus bitstream in a track with the timescale fields of both 270 the Movie Header Box and the Media Header Box set to 48000, we would use the following edit: 271 segment_duration = the number of the valid samples 272 media_time = the number of the priming samples 273 media_rate = 1 << 16 274 275 The Edit List Box is applied to whole movie including all movie fragments. Therefore, it is impossible to tell 276 the actual duration in the case producing movie fragments on the fly such as live-streaming. In such cases, 277 the duration of the last Opus sample may be helpful by setting zero to the segment_duration field since the 278 value 0 represents implicit duration equal to the sum of the duration of all samples. 279 <a name="4.5"></a> 280 4.5 Channel Mapping 281 4.5.1 ISO Base Media native Channel Mapping<a name="4.5.1"></a> 282 ISO Base Media File Format, that is ISO/IEC 14496-12 [1], defines an extension ChannelLayout to the 283 AudioSampleEntry, which conveys information of mapping channels to loudspeaker positions. The ChannelLayout 284 enables to specify the channel layout more flexibly than the predefined layouts of the ChannelMappingFamily. 285 286 To utilize the ChannelLayout for OpusSampleEntry, the ChannelMappingFamily field should be set to 255. 287 Even when the ChannelMappingFamily field is set to another value, the assignment of each output channel to 288 loudspeaker position specified by the ChannelMappingFamily would be changed as specified by the ChannelLayout. 289 The procedure of the assignment is the following. 290 291 1. Decoded channels are mapped to output channels according to the ChannelMappingTable. 292 2. Output channels are mapped to loudspeaker positions according to the ChannelLayout. 293 294 In this way, the parameters of the Opus Specific Box are processed before the ChannelLayout, and the 295 ChannelLayout shall follow the Opus Specific Box. 296 297 4.5.2 Composition on all active tracks (informative)<a name="4.5.2"></a> 298 By the application of alternate_group in the Track Header Box, whole audio channels in all active tracks from 299 non-alternate group and/or different alternate group from each other are composited into the presentation. If 300 an Opus sample consists of multiple Opus bitstreams, it can be splitted into individual Opus bitstreams and 301 reconstructed into new Opus samples as long as every Opus bitstream has the same total duration in each Opus 302 sample. This nature can be utilized to encapsulate a single Opus bitstream in each track without breaking the 303 original channel layout. 304 305 As an example, let's say there is a following track: 306 OutputChannelCount = 6; 307 StreamCount = 4; 308 CoupledCount = 2; 309 ChannelMapping = {0, 4, 1, 2, 3, 5}; // front left, front center, front right, 310 // rear left, rear right, LFE 311 Here, to couple front left to front right channels into the first stream, and couple rear left to rear right 312 channels into the second stream, reordering is needed since coupled streams must precede any non-coupled 313 stream. You extract the four Opus bitstreams from this track and you encapsulate two of the four into a track 314 and the others into another track. The former track is as follows. 315 OutputChannelCount = 6; 316 StreamCount = 2; 317 CoupledCount = 2; 318 ChannelMapping = {0, 255, 1, 2, 3, 255}; // front left, front center, front right, 319 // rear left, rear right, LFE 320 And the latter track is as follows. 321 OutputChannelCount = 6; 322 StreamCount = 2; 323 CoupledCount = 0; 324 ChannelMapping = {255, 0, 255, 255, 255, 1}; // front left, front center, front right, 325 // rear left, rear right, LFE 326 In addition, the value of the alternate_group field in the both tracks is set to 0. As the result, the player 327 may play as if channels with 255 are not present, and play the presentation constructed from the both tracks 328 in the same channel layout as the one of the original track. Keep in mind that the way of the composition, i.e. 329 the mixing for playback, is not defined here, and maybe different results could occur except for the channel 330 layout of the original, depending on an implementation or the definition of a derived file format. 331 332 Note that some derived file formats may specify the restriction to ignore alternate grouping. In the context 333 of such file formats, this application is not available. This unavailability does not mean incompatibilities 334 among file formats unless the restriction to the value of the alternate_group field is specified and brings 335 about any conflict among their definitions. 336 <a name="4.6"></a> 337 4.6 Basic Structure (informative) 338 4.6.1 Initial Movie<a name="4.6.1"></a> 339 This subclause shows a basic structure of the Movie Box as follows: 340 341 +----+----+----+----+----+----+----+----+------------------------------+ 342 |moov| | | | | | | | Movie Box | 343 +----+----+----+----+----+----+----+----+------------------------------+ 344 | |mvhd| | | | | | | Movie Header Box | 345 +----+----+----+----+----+----+----+----+------------------------------+ 346 | |trak| | | | | | | Track Box | 347 +----+----+----+----+----+----+----+----+------------------------------+ 348 | | |tkhd| | | | | | Track Header Box | 349 +----+----+----+----+----+----+----+----+------------------------------+ 350 | | |edts| | | | | | Edit Box | 351 +----+----+----+----+----+----+----+----+------------------------------+ 352 | | | |elst| | | | | Edit List Box | 353 +----+----+----+----+----+----+----+----+------------------------------+ 354 | | |mdia| | | | | | Media Box | 355 +----+----+----+----+----+----+----+----+------------------------------+ 356 | | | |mdhd| | | | | Media Header Box | 357 +----+----+----+----+----+----+----+----+------------------------------+ 358 | | | |hdlr| | | | | Handler Reference Box | 359 +----+----+----+----+----+----+----+----+------------------------------+ 360 | | | |minf| | | | | Media Information Box | 361 +----+----+----+----+----+----+----+----+------------------------------+ 362 | | | | |smhd| | | | Sound Media Header Box | 363 +----+----+----+----+----+----+----+----+------------------------------+ 364 | | | | |dinf| | | | Data Information Box | 365 +----+----+----+----+----+----+----+----+------------------------------+ 366 | | | | | |dref| | | Data Reference Box | 367 +----+----+----+----+----+----+----+----+------------------------------+ 368 | | | | | | |url | | DataEntryUrlBox | 369 +----+----+----+----+----+----+ or +----+------------------------------+ 370 | | | | | | |urn | | DataEntryUrnBox | 371 +----+----+----+----+----+----+----+----+------------------------------+ 372 | | | | |stbl| | | | Sample Table | 373 +----+----+----+----+----+----+----+----+------------------------------+ 374 | | | | | |stsd| | | Sample Description Box | 375 +----+----+----+----+----+----+----+----+------------------------------+ 376 | | | | | | |Opus| | OpusSampleEntry | 377 +----+----+----+----+----+----+----+----+------------------------------+ 378 | | | | | | | |dOps| Opus Specific Box | 379 +----+----+----+----+----+----+----+----+------------------------------+ 380 | | | | | |stts| | | Decoding Time to Sample Box | 381 +----+----+----+----+----+----+----+----+------------------------------+ 382 | | | | | |stsc| | | Sample To Chunk Box | 383 +----+----+----+----+----+----+----+----+------------------------------+ 384 | | | | | |stsz| | | Sample Size Box | 385 +----+----+----+----+----+ or +----+----+------------------------------+ 386 | | | | | |stz2| | | Compact Sample Size Box | 387 +----+----+----+----+----+----+----+----+------------------------------+ 388 | | | | | |stco| | | Chunk Offset Box | 389 +----+----+----+----+----+ or +----+----+------------------------------+ 390 | | | | | |co64| | | Chunk Large Offset Box | 391 +----+----+----+----+----+----+----+----+------------------------------+ 392 | | | | | |sgpd| | | Sample Group Description Box | 393 +----+----+----+----+----+----+----+----+------------------------------+ 394 | | | | | |sbgp| | | Sample to Group Box | 395 +----+----+----+----+----+----+----+----+------------------------------+ 396 | |mvex|* | | | | | | Movie Extends Box | 397 +----+----+----+----+----+----+----+----+------------------------------+ 398 | | |trex|* | | | | | Track Extends Box | 399 +----+----+----+----+----+----+----+----+------------------------------+ 400 401 Figure 2 - Basic structure of Movie Box 402 403 It is strongly recommended that the order of boxes should follow the above structure. 404 Boxes marked with an asterisk (*) may be present. 405 For most boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. The additional boxes 406 and the additional requirements, restrictions and recommendations to the other boxes are described in this 407 specification. 408 409 4.6.2 Movie Fragments<a name="4.6.2"></a> 410 This subclause shows a basic structure of the Movie Fragment Box as follows: 411 412 +----+----+----+----+----+----+----+----+------------------------------+ 413 |moof| | | | | | | | Movie Fragment Box | 414 +----+----+----+----+----+----+----+----+------------------------------+ 415 | |mfhd| | | | | | | Movie Fragment Header Box | 416 +----+----+----+----+----+----+----+----+------------------------------+ 417 | |traf| | | | | | | Track Fragment Box | 418 +----+----+----+----+----+----+----+----+------------------------------+ 419 | | |tfhd| | | | | | Track Fragment Header Box | 420 +----+----+----+----+----+----+----+----+------------------------------+ 421 | | |trun| | | | | | Track Fragment Run Box | 422 +----+----+----+----+----+----+----+----+------------------------------+ 423 | | |sgpd|* | | | | | Sample Group Description Box | 424 +----+----+----+----+----+----+----+----+------------------------------+ 425 | | |sbgp| | | | | | Sample to Group Box | 426 +----+----+----+----+----+----+----+----+------------------------------+ 427 428 Figure 3 - Basic structure of Movie Fragment Box 429 430 It is strongly recommended that the Movie Fragment Header Box and the Track Fragment Header Box be 431 placed first in their container. 432 Boxes marked with an asterisk (*) may be present. 433 For the boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. 434 <a name="4.7"></a> 435 4.7 Example of Encapsulation (informative) 436 [File] 437 size = 17757 438 [ftyp: File Type Box] 439 position = 0 440 size = 24 441 major_brand = Opus : Opus audio coding 442 minor_version = 0 443 compatible_brands 444 brand[0] = Opus : Opus audio coding 445 brand[1] = iso2 : ISO Base Media file format version 2 446 [moov: Movie Box] 447 position = 24 448 size = 757 449 [mvhd: Movie Header Box] 450 position = 32 451 size = 108 452 version = 0 453 flags = 0x000000 454 creation_time = UTC 2014/12/12, 18:41:19 455 modification_time = UTC 2014/12/12, 18:41:19 456 timescale = 48000 457 duration = 33600 (00:00:00.700) 458 rate = 1.000000 459 volume = 1.000000 460 reserved = 0x0000 461 reserved = 0x00000000 462 reserved = 0x00000000 463 transformation matrix 464 | a, b, u | | 1.000000, 0.000000, 0.000000 | 465 | c, d, v | = | 0.000000, 1.000000, 0.000000 | 466 | x, y, w | | 0.000000, 0.000000, 1.000000 | 467 pre_defined = 0x00000000 468 pre_defined = 0x00000000 469 pre_defined = 0x00000000 470 pre_defined = 0x00000000 471 pre_defined = 0x00000000 472 pre_defined = 0x00000000 473 next_track_ID = 2 474 [trak: Track Box] 475 position = 140 476 size = 608 477 [tkhd: Track Header Box] 478 position = 148 479 size = 92 480 version = 0 481 flags = 0x000007 482 Track enabled 483 Track in movie 484 Track in preview 485 creation_time = UTC 2014/12/12, 18:41:19 486 modification_time = UTC 2014/12/12, 18:41:19 487 track_ID = 1 488 reserved = 0x00000000 489 duration = 33600 (00:00:00.700) 490 reserved = 0x00000000 491 reserved = 0x00000000 492 layer = 0 493 alternate_group = 0 494 volume = 1.000000 495 reserved = 0x0000 496 transformation matrix 497 | a, b, u | | 1.000000, 0.000000, 0.000000 | 498 | c, d, v | = | 0.000000, 1.000000, 0.000000 | 499 | x, y, w | | 0.000000, 0.000000, 1.000000 | 500 width = 0.000000 501 height = 0.000000 502 [edts: Edit Box] 503 position = 240 504 size = 36 505 [elst: Edit List Box] 506 position = 281 507 size = 28 508 version = 0 509 flags = 0x000000 510 entry_count = 1 511 entry[0] 512 segment_duration = 33600 513 media_time = 312 514 media_rate = 1.000000 515 [mdia: Media Box] 516 position = 276 517 size = 472 518 [mdhd: Media Header Box] 519 position = 284 520 size = 32 521 version = 0 522 flags = 0x000000 523 creation_time = UTC 2014/12/12, 18:41:19 524 modification_time = UTC 2014/12/12, 18:41:19 525 timescale = 48000 526 duration = 34560 (00:00:00.720) 527 language = und 528 pre_defined = 0x0000 529 [hdlr: Handler Reference Box] 530 position = 316 531 size = 51 532 version = 0 533 flags = 0x000000 534 pre_defined = 0x00000000 535 handler_type = soun 536 reserved = 0x00000000 537 reserved = 0x00000000 538 reserved = 0x00000000 539 name = Xiph Audio Handler 540 [minf: Media Information Box] 541 position = 367 542 size = 381 543 [smhd: Sound Media Header Box] 544 position = 375 545 size = 16 546 version = 0 547 flags = 0x000000 548 balance = 0.000000 549 reserved = 0x0000 550 [dinf: Data Information Box] 551 position = 391 552 size = 36 553 [dref: Data Reference Box] 554 position = 399 555 size = 28 556 version = 0 557 flags = 0x000000 558 entry_count = 1 559 [url : Data Entry Url Box] 560 position = 415 561 size = 12 562 version = 0 563 flags = 0x000001 564 location = in the same file 565 [stbl: Sample Table Box] 566 position = 427 567 size = 321 568 [stsd: Sample Description Box] 569 position = 435 570 size = 79 571 version = 0 572 flags = 0x000000 573 entry_count = 1 574 [Opus: Audio Description] 575 position = 451 576 size = 63 577 reserved = 0x000000000000 578 data_reference_index = 1 579 reserved = 0x0000 580 reserved = 0x0000 581 reserved = 0x00000000 582 channelcount = 6 583 samplesize = 16 584 pre_defined = 0 585 reserved = 0 586 samplerate = 48000.000000 587 [dOps: Opus Specific Box] 588 position = 487 589 size = 27 590 Version = 0 591 OutputChannelCount = 6 592 PreSkip = 312 593 InputSampleRate = 48000 594 OutputGain = 0 595 ChannelMappingFamily = 1 596 StreamCount = 4 597 CoupledCount = 2 598 ChannelMapping 599 0 -> 0: front left 600 1 -> 4: fron center 601 2 -> 1: front right 602 3 -> 2: side left 603 4 -> 3: side right 604 5 -> 5: rear center 605 [stts: Decoding Time to Sample Box] 606 position = 514 607 size = 24 608 version = 0 609 flags = 0x000000 610 entry_count = 1 611 entry[0] 612 sample_count = 18 613 sample_delta = 1920 614 [stsc: Sample To Chunk Box] 615 position = 538 616 size = 40 617 version = 0 618 flags = 0x000000 619 entry_count = 2 620 entry[0] 621 first_chunk = 1 622 samples_per_chunk = 13 623 sample_description_index = 1 624 entry[1] 625 first_chunk = 2 626 samples_per_chunk = 5 627 sample_description_index = 1 628 [stsz: Sample Size Box] 629 position = 578 630 size = 92 631 version = 0 632 flags = 0x000000 633 sample_size = 0 (variable) 634 sample_count = 18 635 entry_size[0] = 977 636 entry_size[1] = 938 637 entry_size[2] = 939 638 entry_size[3] = 938 639 entry_size[4] = 934 640 entry_size[5] = 945 641 entry_size[6] = 948 642 entry_size[7] = 956 643 entry_size[8] = 955 644 entry_size[9] = 930 645 entry_size[10] = 933 646 entry_size[11] = 934 647 entry_size[12] = 972 648 entry_size[13] = 977 649 entry_size[14] = 958 650 entry_size[15] = 949 651 entry_size[16] = 962 652 entry_size[17] = 848 653 [stco: Chunk Offset Box] 654 position = 670 655 size = 24 656 version = 0 657 flags = 0x000000 658 entry_count = 2 659 chunk_offset[0] = 797 660 chunk_offset[1] = 13096 661 [sgpd: Sample Group Description Box] 662 position = 694 663 size = 26 664 version = 1 665 flags = 0x000000 666 grouping_type = roll 667 default_length = 2 (constant) 668 entry_count = 1 669 roll_distance[0] = -2 670 [sbgp: Sample to Group Box] 671 position = 720 672 size = 28 673 version = 0 674 flags = 0x000000 675 grouping_type = roll 676 entry_count = 1 677 entry[0] 678 sample_count = 18 679 group_description_index = 1 680 [free: Free Space Box] 681 position = 748 682 size = 8 683 [mdat: Media Data Box] 684 position = 756 685 size = 17001 686 <a name="5"></a> 687 5 Authors' Address 688 Yusuke Nakamura 689 Email: muken.the.vfrmaniac |at| gmail.com 690 </div> 691 </body> 692 </html> 693
