International organisation for standardisation organisation internationale de normalisation

Summary of discussions

4. Action Points / Ballots

ITU-T H.222.0 (06/2012)|ISO/IEC 13818-1:2013/DAM 5 (SC 29 N 13749)

Systems AMENDMENT 5: Transport of MVC depth video sub-bitstream and extensions to support HEVC low delay coding mode

DAM (2014-01-31)

3. MPEG-4 ISO Base File Format (14496-12)

   1. Topics

      1. ISO/IEC 14496-12:201X/AMD 3: Font streams and other improvements to file format

2. ISO/IEC 14496-12:201X/AMD 4: Enhanced audio support

This amendment enhances the codec-independent support for audio in the file format, adding the ability to declare downmixing and dynamic range control of audio, and describe the loudness of the program, before or after downmix or dynamic range control. It also supports the codec-independent declaration of channel layout, and identifying the carriage of DRC coefficients both in the audio stream, and in a separate track.

2. Contributions

Number	Session	Title	Source	Dispositions
m31431	File Format	Error(s) in 14496-12/Amd.2	David Singer, Cyril Concolato	Accepted N13957
m31433	File Format	Updating the conformance tracking for the file format	David Singer	Noted
m31436	File Format	Inputs for ISOBMFF PDAM3	Jean Le Feuvre, Cyril Concolato, Franck Denoual, Frédéric Mazé, Eric Nassor	Accepted N13954
m31443	File Format	On Initial tfdt value	Jean Le Feuvre	Accepted N13957
m31470	File Format	Improved audio support in the ISO Base Media File Format	David Singer, Frank Baumgarte,	Accepted N13955
M31681		Preliminary EBU input on the carriage of timed text in 14496-12	Nigel Megitt, Andreas Tai	Accepted N13957

3. Summary of discussions

1. m31431 Error(s) in 14496-12/Amd.2

We note that 29240 (Incheon) was accepted and had the config box, and so its omission is an error. However, so as not to disturb TTML storage we will also issue a COR there to say a config box must not be used in this case.

2. m31443 SIDX Clarification

Into the COR, with the previous.

1. m31436 Inputs for ISOBMFF PDAM3

1. 
   Yes, the sample groups should have >=1 in both places.
   
2. 
   If grouping_type_parameter is not defined for a given grouping_type, then there shall be only one occurrence of this box with this grouping_type.
   
3. 
   If flags have no semantics for a given coding system, the flags shall be 0.
   

(Note also the need for a new brand, below under part 15, into the study).

4. m31681 Preliminary EBU input on the carriage of timed text in 14496-12

There are a number of clarifications that need to be inserted into the COR of part 12 or part 30, as appropriate. Editors to draft a liaison response and matching COR text.

5. m31433 Updating the conformance tracking for the file format

Editors to update the spreadsheet with the new features, and we send a liaison asking for conformance files. At the next meeting, we will ask for volunteers on the conformance files and reference software.

6. m31470 Improved audio support in the ISO Base Media File Format

We note SCTE and ATSC have done some work in the loudness area; do we need to look at it, or send a liaison? Does SMPTE have practices in this area?

We note that a specification will need the usual mandatory/count material on the boxes. And we want to check that these structures work for e.g. radio, and with other aspects of the file format (e.g. updating user-data).

In the joint meeting with audio, there was some concern expressed over whether these structures were too ‘expansive’ for some environments, notably where they would need to be carouseled. There was also concern with the idea that some tracks could represent only some of the channels for a given configuration. Debate is needed as to how much is desirable at the file-format ‘codec independent’ level, and how much in the audio bitstreams (necessarily codec-specific), and how much overlap is desirable, and if it exists, what matching or precedence rules would be needed.

Other contributions pointed out the possible need for ‘headroom’ declaration in the DRC information (a new field), and for ‘mix level’ as a possible ‘loudness’ measure (a new measure definition).

We recognized the pressure to address some of these concerns (notably the loudness information), and the plan is to fast-track this work starting in San Jose (2-months, DAM in Valencia, and final by the fall).

4.