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| <b><u>Encapsulation of Opus in ISO Base Media File Format</u></b><br> |
| <font size="2">last updated: August 28, 2018</font><br> |
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| Encapsulation of Opus in ISO Base Media File Format |
| Version 0.8.1 (incomplete) |
| |
| |
| Table of Contents |
| <a href="#1">1</a> Scope |
| <a href="#2">2</a> Normative References |
| <a href="#3">3</a> Terms and Definitions |
| <a href="#4">4</a> Design Rules of Encapsulation |
| <a href="#4.1">4.1</a> File Type Identification |
| <a href="#4.2">4.2</a> Overview of Track Structure |
| <a href="#4.3">4.3</a> Definitions of Opus sample |
| <a href="#4.3.1">4.3.1</a> Sample entry format |
| <a href="#4.3.2">4.3.2</a> Opus Specific Box |
| <a href="#4.3.3">4.3.3</a> Sample format |
| <a href="#4.3.4">4.3.4</a> Duration of Opus sample |
| <a href="#4.3.5">4.3.5</a> Sub-sample |
| <a href="#4.3.6">4.3.6</a> Random Access |
| <a href="#4.3.6.1">4.3.6.1</a> Random Access Point |
| <a href="#4.3.6.2">4.3.6.2</a> Pre-roll |
| <a href="#4.4">4.4</a> Trimming of Actual Duration |
| <a href="#4.5">4.5</a> Channel Mapping |
| <a href="#4.5.1">4.5.1</a> ISO Base Media native Channel Mapping |
| <a href="#4.5.2">4.5.2</a> Composition on all active tracks (informative) |
| <a href="#4.6">4.6</a> Basic Structure (informative) |
| <a href="#4.6.1">4.6.2</a> Initial Movie |
| <a href="#4.6.2">4.6.3</a> Movie Fragments |
| <a href="#4.7">4.7</a> Example of Encapsulation (informative) |
| <a href="#5">5</a> Author's Address |
| |
| <a name="1"></a> |
| 1 Scope |
| This specification specifies the fundamental way of the encapsulation of Opus coded bitstreams in ISO Base Media |
| file format and its derivatives. The encapsulation of Opus coded bitstreams in QuickTime file format is outside |
| the scope of this specification. |
| |
| <a name="2"></a> |
| 2 Normative References |
| [1] ISO/IEC 14496-12:2015 Corrected version |
| Information technology — Coding of audio-visual objects — Part 12: ISO base media file format |
| |
| [2] RFC 6716 |
| Definition of the Opus Audio Codec |
| |
| [3] RFC 7845 |
| Ogg Encapsulation for the Opus Audio Codec |
| |
| <a name="3"></a> |
| 3 Terms and Definitions |
| 3.1 active track |
| enabled track from the non-alternate group or selected track from alternate group |
| |
| 3.2 actual duration |
| duration constructed from valid samples |
| |
| 3.3 edit |
| entry in the Edit List Box |
| |
| 3.4 padded samples |
| PCM samples after decoding Opus sample(s) which are not valid samples |
| An Opus bitstream always contains them partially at the beginning and may contain them in part at the end, as |
| long as not physically removed yet at the beginning and/or the end. |
| |
| 3.5 priming samples |
| padded samples at the beginning of the Opus bitstream |
| |
| 3.6 sample-accurate |
| for any PCM sample, a timestamp exactly matching its sampling timestamp is present in the media timeline. |
| |
| 3.7 valid samples |
| PCM samples after decoding Opus sample(s) corresponding to input PCM samples |
| |
| <a name="4"></a> |
| 4 Design Rules of Encapsulation |
| 4.1 File Type Identification<a name="4.1"></a> |
| This specification defines the brand 'Opus' to declare files are conformant to this specification. Additionally, |
| files conformant to this specification shall contain at least one brand, which supports the requirements and the |
| requirements described in this clause without contradiction, in the compatible brands list of the File Type Box. |
| As an example, the minimal support of the encapsulation of Opus bitstreams in ISO Base Media file format requires |
| the 'iso2' brand in the compatible brands list since support of roll groups is required. |
| <a name="4.2"></a> |
| 4.2 Overview of Track Structure |
| This clause summarizes requirements of the encapsulation of Opus coded bitstream as media data in audio tracks |
| in file formats compliant with the ISO Base Media File Format. The details are described in clauses after this |
| clause. |
| + The handler_type field in the Handler Reference Box shall be set to 'soun'. |
| + The Media Information Box shall contain the Sound Media Header Box. |
| + The codingname of the sample entry is 'Opus'. |
| This specification does not define any encapsulation using MP4AudioSampleEntry with objectTypeIndication |
| specified by the MPEG-4 Registration Authority (http://www.mp4ra.org/). |
| See 4.3.1 Sample entry format to get the details about the sample entry. |
| + The 'dOps' box is added to the sample entry to convey initializing information for the decoder. |
| See 4.3.2 Opus Specific Box to get the details. |
| + An Opus sample is exactly one Opus packet for each of different Opus bitstreams. |
| See 4.3.3 Sample format to get the details. |
| + Every Opus sample is a sync sample but requires pre-roll for every random access to get correct output. |
| See 4.3.6 Random Access to get the details. |
| <a name="4.3"></a> |
| 4.3 Definitions of Opus sample |
| 4.3.1 Sample entry format<a name="4.3.1"></a> |
| For any track containing Opus bitstreams, at least one sample entry describing corresponding Opus bitstream |
| shall be present inside the Sample Table Box. This version of the specification defines only one sample |
| entry format named OpusSampleEntry whose codingname is 'Opus'. This sample entry includes exactly one Opus |
| Specific Box defined in 4.3.2 as a mandatory box and indicates that Opus samples described by this sample |
| entry are stored by the sample format described in 4.3.3. |
| |
| The syntax and semantics of the OpusSampleEntry is shown as follows. |
| |
| class OpusSampleEntry() extends AudioSampleEntry ('Opus') { |
| OpusSpecificBox(); |
| } |
| |
| + channelcount: |
| The channelcount field indicates the number of output channels and shall be set to the same value of |
| the OutputChannelCount in the OpusDecoderConfigurationRecord. The value of this field may be used in |
| the ChannelLayout if any as described in 4.5.1. |
| + samplesize: |
| The samplesize field shall be set to 16. |
| + samplerate: |
| The samplerate field shall be set to 48000<<16. |
| + OpusSpecificBox |
| This box contains initializing information for the decoder as defined in 4.3.2. |
| |
| 4.3.2 Opus Specific Box<a name="4.3.2"></a> |
| Exactly one Opus Specific Box shall be present in each OpusSampleEntry. |
| The Opus Specific Box contains an OpusDecoderConfigurationRecord which contains the Version field and |
| this specification defines version 0 of this record. If incompatible changes occured in the fields after |
| the Version field within the OpusDecoderConfigurationRecord in the future versions of this specification, |
| another version will be defined. |
| This box refers to Ogg Opus [3] at many parts but all the data are stored as big-endian format. |
| |
| The syntax and semantics of the Opus Specific Box is shown as follows. |
| |
| class ChannelMappingTable (unsigned int(8) OutputChannelCount) { |
| unsigned int(8) StreamCount; |
| unsigned int(8) CoupledCount; |
| unsigned int(8 * OutputChannelCount) ChannelMapping; |
| } |
| |
| aligned(8) class OpusDecoderConfigurationRecord { |
| unsigned int(8) Version; |
| unsigned int(8) OutputChannelCount; |
| unsigned int(16) PreSkip; |
| unsigned int(32) InputSampleRate; |
| signed int(16) OutputGain; |
| unsigned int(8) ChannelMappingFamily; |
| if (ChannelMappingFamily != 0) { |
| ChannelMappingTable(OutputChannelCount); |
| } |
| } |
| |
| class OpusSpecificBox extends Box('dOps') { |
| OpusDecoderConfigurationRecord() OpusConfig; |
| } |
| |
| + Version: |
| The Version field shall be set to 0. |
| In the future versions of this specification, this field may be set to other values. And without support |
| of those values, the reader shall not read the fields after this within the OpusSpecificBox. |
| + OutputChannelCount: |
| The OutputChannelCount field shall be set to the same value as the *Output Channel Count* field in the |
| identification header defined in Ogg Opus [3]. |
| + PreSkip: |
| The PreSkip field indicates the number of the priming samples, that is, the number of samples at 48000 Hz |
| to discard from the decoder output when starting playback. The value of the PreSkip field shall be at least |
| 80 milliseconds' worth of PCM samples even when removing any number of Opus samples which may or may not |
| contain the priming samples. The PreSkip field is not used for discarding the priming samples at the whole |
| playback at all since it is informative only, and that task falls on the Edit List Box. |
| + InputSampleRate: |
| The InputSampleRate field shall be set to the same value as the *Input Sample Rate* field in the |
| identification header defined in Ogg Opus [3]. |
| + OutputGain: |
| The OutputGain field shall be set to the same value as the *Output Gain* field in the identification |
| header define in Ogg Opus [3]. Note that the value is stored as 8.8 fixed-point. |
| + ChannelMappingFamily: |
| The ChannelMappingFamily field shall be set to the same value as the *Channel Mapping Family* field in |
| the identification header defined in Ogg Opus [3]. Note that the value 255 may be used for an alternative |
| to map channels by ISO Base Media native mapping. The details are described in 4.5.1. |
| + StreamCount: |
| The StreamCount field shall be set to the same value as the *Stream Count* field in the identification |
| header defined in Ogg Opus [3]. |
| + CoupledCount: |
| The CoupledCount field shall be set to the same value as the *Coupled Count* field in the identification |
| header defined in Ogg Opus [3]. |
| + ChannelMapping: |
| The ChannelMapping field shall be set to the same octet string as *Channel Mapping* field in the identi- |
| fication header defined in Ogg Opus [3]. |
| |
| 4.3.3 Sample format<a name="4.3.3"></a> |
| An Opus sample is exactly one Opus packet for each of different Opus bitstreams. Due to support more than |
| two channels, an Opus sample can contain frames from multiple Opus bitstreams but all Opus packets shall |
| share with the total of frame sizes in a single Opus sample. The way of how to pack an Opus packet from |
| each of Opus bitstreams into a single Opus sample follows Appendix B. in RFC 6716 [2]. |
| The endianness has nothing to do with any Opus sample since every Opus packet is processed byte-by-byte. |
| In this specification, 'sample' means 'Opus sample' except for 'padded samples', 'priming samples', 'valid |
| sample' and 'sample-accurate', i.e. 'sample' is 'sample' in the term defined in ISO/IEC 14496-12 [1]. |
| |
| +-----------------------------------------+-------------------------------------+ |
| | Opus packet 0 (self-delimiting framing) | Opus packet 1 (undelimited framing) | |
| +-----------------------------------------+-------------------------------------+ |
| |<---------------------------- the size of Opus sample ------------------------>| |
| |
| Figure 1 - Example structure of an Opus sample containing two Opus bitstreams |
| |
| 4.3.4 Duration of Opus sample<a name="4.3.4"></a> |
| The duration of Opus sample is given by multiplying the total of frame sizes for a single Opus bitstream |
| expressed in seconds by the value of the timescale field in the Media Header Box. |
| Let's say an Opus sample consists of two Opus bitstreams, where the frame size of one bitstream is 40 milli- |
| seconds and the frame size of another is 60 milliseconds, and the timescale field in the Media Header Box |
| is set to 48000, then the duration of that Opus sample shall be 120 milliseconds since three 40 millisecond |
| frame and two 60 millisecond frames shall be contained because of the maximum duration of Opus packet, 120 |
| milliseconds, and 5760 in the timescale indicated in the Media Header Box. |
| |
| To indicate the valid samples excluding the padded samples at the end of Opus bitstream, the duration of |
| the last Opus sample of an Opus bitstream is given by multiplying the number of the valid samples by the |
| value produced by dividing the value of the timescale field in the Media Header Box by 48000. |
| |
| 4.3.5 Sub-sample<a name="4.3.5"></a> |
| The structure of the last Opus packet in an Opus sample is different from the others in the same Opus sample, |
| and the others are invalid Opus packets as an Opus sample because of self-delimiting framing. To avoid |
| complexities, sub-sample is not defined for Opus sample in this specification. |
| |
| 4.3.6 Random Access<a name="4.3.6"></a> |
| This subclause describes the nature of the random access of Opus sample. |
| |
| 4.3.6.1 Random Access Point<a name="4.3.6.1"></a> |
| All Opus samples can be independently decoded i.e. every Opus sample is a sync sample. Therefore, the |
| Sync Sample Box shall not be present as long as there are no samples other than Opus samples in the same |
| track. And the sample_is_non_sync_sample field for Opus samples shall be set to 0. |
| |
| 4.3.6.2 Pre-roll<a name="4.3.6.2"></a> |
| Opus bitstream requires at least 80 millisecond pre-roll after each random access to get correct output. |
| Pre-roll is indicated by the roll_distance field in AudioRollRecoveryEntry. AudioPreRollEntry shall not |
| be used since every Opus sample is a sync sample in Opus bitstream. Note that roll_distance is expressed |
| in sample units in a term of ISO Base Media File Format, and always takes negative values. |
| |
| For any track containing Opus bitstreams, at least one Sample Group Description Box and at least one |
| Sample to Group Box within the Sample Table Box shall be present and these have the grouping_type field |
| set to 'roll'. If any Opus sample is contained in a track fragment, the Sample to Group Box with the |
| grouping_type field set to 'roll' shall be present for that track fragment. |
| |
| For the requirement of AudioRollRecoveryEntry, the compatible_brands field in the File Type Box shall |
| contain at least one brand which requires support for roll groups. |
| <a name="4.4"></a> |
| 4.4 Trimming of Actual Duration |
| Due to the priming samples (or the padding at the beginning) derived from the pre-roll for the startup and the |
| padded samples at the end, we need trim from media to get the actual duration. An edit in the Edit List Box can |
| achieve this demand, and the Edit Box and the Edit List Box shall be present. |
| |
| For sample-accurate trimming, proper timescale should be set to the timescale field in the Movie Header Box |
| and the Media Header Box inside Track Box(es) for Opus bitstream. The timescale field in the Media Header Box is |
| typically set to 48000. It is recommended that the timescale field in the Movie Header Box be set to the same |
| value of the timescale field in the Media Header Box in order to avoid the rounding problem when specifying |
| duration of edit if the timescales in all of the Media Header Boxes are set to the same value. |
| |
| For example, to indicate the actual duration of an Opus bitstream in a track with the timescale fields of both |
| the Movie Header Box and the Media Header Box set to 48000, we would use the following edit: |
| segment_duration = the number of the valid samples |
| media_time = the number of the priming samples |
| media_rate = 1 << 16 |
| |
| The Edit List Box is applied to whole movie including all movie fragments. Therefore, it is impossible to tell |
| the actual duration in the case producing movie fragments on the fly such as live-streaming. In such cases, |
| the duration of the last Opus sample may be helpful by setting zero to the segment_duration field since the |
| value 0 represents implicit duration equal to the sum of the duration of all samples. |
| <a name="4.5"></a> |
| 4.5 Channel Mapping |
| 4.5.1 ISO Base Media native Channel Mapping<a name="4.5.1"></a> |
| ISO Base Media File Format, that is ISO/IEC 14496-12 [1], defines an extension ChannelLayout to the |
| AudioSampleEntry, which conveys information of mapping channels to loudspeaker positions. The ChannelLayout |
| enables to specify the channel layout more flexibly than the predefined layouts of the ChannelMappingFamily. |
| |
| To utilize the ChannelLayout for OpusSampleEntry, the ChannelMappingFamily field should be set to 255. |
| Even when the ChannelMappingFamily field is set to another value, the assignment of each output channel to |
| loudspeaker position specified by the ChannelMappingFamily would be changed as specified by the ChannelLayout. |
| The procedure of the assignment is the following. |
| |
| 1. Decoded channels are mapped to output channels according to the ChannelMappingTable. |
| 2. Output channels are mapped to loudspeaker positions according to the ChannelLayout. |
| |
| In this way, the parameters of the Opus Specific Box are processed before the ChannelLayout, and the |
| ChannelLayout shall follow the Opus Specific Box. |
| |
| 4.5.2 Composition on all active tracks (informative)<a name="4.5.2"></a> |
| By the application of alternate_group in the Track Header Box, whole audio channels in all active tracks from |
| non-alternate group and/or different alternate group from each other are composited into the presentation. If |
| an Opus sample consists of multiple Opus bitstreams, it can be splitted into individual Opus bitstreams and |
| reconstructed into new Opus samples as long as every Opus bitstream has the same total duration in each Opus |
| sample. This nature can be utilized to encapsulate a single Opus bitstream in each track without breaking the |
| original channel layout. |
| |
| As an example, let's say there is a following track: |
| OutputChannelCount = 6; |
| StreamCount = 4; |
| CoupledCount = 2; |
| ChannelMapping = {0, 4, 1, 2, 3, 5}; // front left, front center, front right, |
| // rear left, rear right, LFE |
| Here, to couple front left to front right channels into the first stream, and couple rear left to rear right |
| channels into the second stream, reordering is needed since coupled streams must precede any non-coupled |
| stream. You extract the four Opus bitstreams from this track and you encapsulate two of the four into a track |
| and the others into another track. The former track is as follows. |
| OutputChannelCount = 6; |
| StreamCount = 2; |
| CoupledCount = 2; |
| ChannelMapping = {0, 255, 1, 2, 3, 255}; // front left, front center, front right, |
| // rear left, rear right, LFE |
| And the latter track is as follows. |
| OutputChannelCount = 6; |
| StreamCount = 2; |
| CoupledCount = 0; |
| ChannelMapping = {255, 0, 255, 255, 255, 1}; // front left, front center, front right, |
| // rear left, rear right, LFE |
| In addition, the value of the alternate_group field in the both tracks is set to 0. As the result, the player |
| may play as if channels with 255 are not present, and play the presentation constructed from the both tracks |
| in the same channel layout as the one of the original track. Keep in mind that the way of the composition, i.e. |
| the mixing for playback, is not defined here, and maybe different results could occur except for the channel |
| layout of the original, depending on an implementation or the definition of a derived file format. |
| |
| Note that some derived file formats may specify the restriction to ignore alternate grouping. In the context |
| of such file formats, this application is not available. This unavailability does not mean incompatibilities |
| among file formats unless the restriction to the value of the alternate_group field is specified and brings |
| about any conflict among their definitions. |
| <a name="4.6"></a> |
| 4.6 Basic Structure (informative) |
| 4.6.1 Initial Movie<a name="4.6.1"></a> |
| This subclause shows a basic structure of the Movie Box as follows: |
| |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| |moov| | | | | | | | Movie Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | |mvhd| | | | | | | Movie Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | |trak| | | | | | | Track Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |tkhd| | | | | | Track Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |edts| | | | | | Edit Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | |elst| | | | | Edit List Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |mdia| | | | | | Media Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | |mdhd| | | | | Media Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | |hdlr| | | | | Handler Reference Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | |minf| | | | | Media Information Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | |smhd| | | | Sound Media Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | |dinf| | | | Data Information Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |dref| | | Data Reference Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | | |url | | DataEntryUrlBox | |
| +----+----+----+----+----+----+ or +----+------------------------------+ |
| | | | | | | |urn | | DataEntryUrnBox | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | |stbl| | | | Sample Table | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |stsd| | | Sample Description Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | | |Opus| | OpusSampleEntry | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | | | |dOps| Opus Specific Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |stts| | | Decoding Time to Sample Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |stsc| | | Sample To Chunk Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |stsz| | | Sample Size Box | |
| +----+----+----+----+----+ or +----+----+------------------------------+ |
| | | | | | |stz2| | | Compact Sample Size Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |stco| | | Chunk Offset Box | |
| +----+----+----+----+----+ or +----+----+------------------------------+ |
| | | | | | |co64| | | Chunk Large Offset Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |sgpd| | | Sample Group Description Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | | | | |sbgp| | | Sample to Group Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | |mvex|* | | | | | | Movie Extends Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |trex|* | | | | | Track Extends Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| |
| Figure 2 - Basic structure of Movie Box |
| |
| It is strongly recommended that the order of boxes should follow the above structure. |
| Boxes marked with an asterisk (*) may be present. |
| For most boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. The additional boxes |
| and the additional requirements, restrictions and recommendations to the other boxes are described in this |
| specification. |
| |
| 4.6.2 Movie Fragments<a name="4.6.2"></a> |
| This subclause shows a basic structure of the Movie Fragment Box as follows: |
| |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| |moof| | | | | | | | Movie Fragment Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | |mfhd| | | | | | | Movie Fragment Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | |traf| | | | | | | Track Fragment Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |tfhd| | | | | | Track Fragment Header Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |trun| | | | | | Track Fragment Run Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |sgpd|* | | | | | Sample Group Description Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| | | |sbgp| | | | | | Sample to Group Box | |
| +----+----+----+----+----+----+----+----+------------------------------+ |
| |
| Figure 3 - Basic structure of Movie Fragment Box |
| |
| It is strongly recommended that the Movie Fragment Header Box and the Track Fragment Header Box be |
| placed first in their container. |
| Boxes marked with an asterisk (*) may be present. |
| For the boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. |
| <a name="4.7"></a> |
| 4.7 Example of Encapsulation (informative) |
| [File] |
| size = 17757 |
| [ftyp: File Type Box] |
| position = 0 |
| size = 24 |
| major_brand = Opus : Opus audio coding |
| minor_version = 0 |
| compatible_brands |
| brand[0] = Opus : Opus audio coding |
| brand[1] = iso2 : ISO Base Media file format version 2 |
| [moov: Movie Box] |
| position = 24 |
| size = 757 |
| [mvhd: Movie Header Box] |
| position = 32 |
| size = 108 |
| version = 0 |
| flags = 0x000000 |
| creation_time = UTC 2014/12/12, 18:41:19 |
| modification_time = UTC 2014/12/12, 18:41:19 |
| timescale = 48000 |
| duration = 33600 (00:00:00.700) |
| rate = 1.000000 |
| volume = 1.000000 |
| reserved = 0x0000 |
| reserved = 0x00000000 |
| reserved = 0x00000000 |
| transformation matrix |
| | a, b, u | | 1.000000, 0.000000, 0.000000 | |
| | c, d, v | = | 0.000000, 1.000000, 0.000000 | |
| | x, y, w | | 0.000000, 0.000000, 1.000000 | |
| pre_defined = 0x00000000 |
| pre_defined = 0x00000000 |
| pre_defined = 0x00000000 |
| pre_defined = 0x00000000 |
| pre_defined = 0x00000000 |
| pre_defined = 0x00000000 |
| next_track_ID = 2 |
| [trak: Track Box] |
| position = 140 |
| size = 608 |
| [tkhd: Track Header Box] |
| position = 148 |
| size = 92 |
| version = 0 |
| flags = 0x000007 |
| Track enabled |
| Track in movie |
| Track in preview |
| creation_time = UTC 2014/12/12, 18:41:19 |
| modification_time = UTC 2014/12/12, 18:41:19 |
| track_ID = 1 |
| reserved = 0x00000000 |
| duration = 33600 (00:00:00.700) |
| reserved = 0x00000000 |
| reserved = 0x00000000 |
| layer = 0 |
| alternate_group = 0 |
| volume = 1.000000 |
| reserved = 0x0000 |
| transformation matrix |
| | a, b, u | | 1.000000, 0.000000, 0.000000 | |
| | c, d, v | = | 0.000000, 1.000000, 0.000000 | |
| | x, y, w | | 0.000000, 0.000000, 1.000000 | |
| width = 0.000000 |
| height = 0.000000 |
| [edts: Edit Box] |
| position = 240 |
| size = 36 |
| [elst: Edit List Box] |
| position = 281 |
| size = 28 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 1 |
| entry[0] |
| segment_duration = 33600 |
| media_time = 312 |
| media_rate = 1.000000 |
| [mdia: Media Box] |
| position = 276 |
| size = 472 |
| [mdhd: Media Header Box] |
| position = 284 |
| size = 32 |
| version = 0 |
| flags = 0x000000 |
| creation_time = UTC 2014/12/12, 18:41:19 |
| modification_time = UTC 2014/12/12, 18:41:19 |
| timescale = 48000 |
| duration = 34560 (00:00:00.720) |
| language = und |
| pre_defined = 0x0000 |
| [hdlr: Handler Reference Box] |
| position = 316 |
| size = 51 |
| version = 0 |
| flags = 0x000000 |
| pre_defined = 0x00000000 |
| handler_type = soun |
| reserved = 0x00000000 |
| reserved = 0x00000000 |
| reserved = 0x00000000 |
| name = Xiph Audio Handler |
| [minf: Media Information Box] |
| position = 367 |
| size = 381 |
| [smhd: Sound Media Header Box] |
| position = 375 |
| size = 16 |
| version = 0 |
| flags = 0x000000 |
| balance = 0.000000 |
| reserved = 0x0000 |
| [dinf: Data Information Box] |
| position = 391 |
| size = 36 |
| [dref: Data Reference Box] |
| position = 399 |
| size = 28 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 1 |
| [url : Data Entry Url Box] |
| position = 415 |
| size = 12 |
| version = 0 |
| flags = 0x000001 |
| location = in the same file |
| [stbl: Sample Table Box] |
| position = 427 |
| size = 321 |
| [stsd: Sample Description Box] |
| position = 435 |
| size = 79 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 1 |
| [Opus: Audio Description] |
| position = 451 |
| size = 63 |
| reserved = 0x000000000000 |
| data_reference_index = 1 |
| reserved = 0x0000 |
| reserved = 0x0000 |
| reserved = 0x00000000 |
| channelcount = 6 |
| samplesize = 16 |
| pre_defined = 0 |
| reserved = 0 |
| samplerate = 48000.000000 |
| [dOps: Opus Specific Box] |
| position = 487 |
| size = 27 |
| Version = 0 |
| OutputChannelCount = 6 |
| PreSkip = 312 |
| InputSampleRate = 48000 |
| OutputGain = 0 |
| ChannelMappingFamily = 1 |
| StreamCount = 4 |
| CoupledCount = 2 |
| ChannelMapping |
| 0 -> 0: front left |
| 1 -> 4: fron center |
| 2 -> 1: front right |
| 3 -> 2: side left |
| 4 -> 3: side right |
| 5 -> 5: rear center |
| [stts: Decoding Time to Sample Box] |
| position = 514 |
| size = 24 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 1 |
| entry[0] |
| sample_count = 18 |
| sample_delta = 1920 |
| [stsc: Sample To Chunk Box] |
| position = 538 |
| size = 40 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 2 |
| entry[0] |
| first_chunk = 1 |
| samples_per_chunk = 13 |
| sample_description_index = 1 |
| entry[1] |
| first_chunk = 2 |
| samples_per_chunk = 5 |
| sample_description_index = 1 |
| [stsz: Sample Size Box] |
| position = 578 |
| size = 92 |
| version = 0 |
| flags = 0x000000 |
| sample_size = 0 (variable) |
| sample_count = 18 |
| entry_size[0] = 977 |
| entry_size[1] = 938 |
| entry_size[2] = 939 |
| entry_size[3] = 938 |
| entry_size[4] = 934 |
| entry_size[5] = 945 |
| entry_size[6] = 948 |
| entry_size[7] = 956 |
| entry_size[8] = 955 |
| entry_size[9] = 930 |
| entry_size[10] = 933 |
| entry_size[11] = 934 |
| entry_size[12] = 972 |
| entry_size[13] = 977 |
| entry_size[14] = 958 |
| entry_size[15] = 949 |
| entry_size[16] = 962 |
| entry_size[17] = 848 |
| [stco: Chunk Offset Box] |
| position = 670 |
| size = 24 |
| version = 0 |
| flags = 0x000000 |
| entry_count = 2 |
| chunk_offset[0] = 797 |
| chunk_offset[1] = 13096 |
| [sgpd: Sample Group Description Box] |
| position = 694 |
| size = 26 |
| version = 1 |
| flags = 0x000000 |
| grouping_type = roll |
| default_length = 2 (constant) |
| entry_count = 1 |
| roll_distance[0] = -2 |
| [sbgp: Sample to Group Box] |
| position = 720 |
| size = 28 |
| version = 0 |
| flags = 0x000000 |
| grouping_type = roll |
| entry_count = 1 |
| entry[0] |
| sample_count = 18 |
| group_description_index = 1 |
| [free: Free Space Box] |
| position = 748 |
| size = 8 |
| [mdat: Media Data Box] |
| position = 756 |
| size = 17001 |
| <a name="5"></a> |
| 5 Authors' Address |
| Yusuke Nakamura |
| Email: muken.the.vfrmaniac |at| gmail.com |
| </div> |
| </body> |
| </html> |
