[Matroska-devel] requesting "AvgTimePerFrame" or "FieldRate" header field

madshi madshi at gmail.com
Thu Oct 8 15:33:00 CEST 2015


2015-10-04 17:28 GMT+02:00 Steve Lhomme <slhomme at matroska.org>:
> 2015-09-23 18:26 GMT+02:00 madshi <madshi at gmail.com>:
>> Hi Steve,
>>
>> sorry to revive such an old "thread", but since you're currently
>> actively working on extending the MKV spec, maybe you can take this
>> old wish of mine into account now, too? I think MKV is really missing
>> this specific piece of information as of yet.
>
> It may not need an extra field. If we go with a fraction for the
> TrackTimecodeScale it should probably be it. As mentioned in the other
> thread VFR would have a problem with this.
> Otherwise an extra value per track should be possible, and marked as
> informational only. We already have the
> http://matroska.org/technical/specs/index.html#FrameRate field that
> has been deprecated. It's a damn float ;)

I'm not sure how TrackTimecodeScale would help? It seems to define how
fast one track needs to be played in comparison to other tracks. What
I'm looking for is a relatively simple "FieldRate" information field
which simply tells us how many fields per second the video track
contains. Can't get much simpler than that. It should pretty much be a
copy of the same information from the video bitstream.

E.g. see h264 and HEVC spec "num_units_in_tick" and "time_scale"
information fields.

Best regards, Mathias.


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