[FFmpeg-devel] Why the tag “DURATION” is a necessity in Matroska files?

[21naown at gmail.com]

Le 16/06/2017 à 16:04, wm4 a écrit :
> On Fri, 16 Jun 2017 15:43:51 +0200
> 21naown at gmail.com wrote:
>
>> Le 16/06/2017 à 14:25, wm4 a écrit :
>>> On Fri, 16 Jun 2017 13:51:20 +0200
>>> 21naown at gmail.com wrote:
>>>   
>>>> Le 16/06/2017 à 12:55, wm4 a écrit :
>>>>> On Fri, 16 Jun 2017 02:32:10 +0200
>>>>> 21naown at gmail.com wrote:
>>>>>      
>>>>>> Hello,
>>>>>>
>>>>>>
>>>>>> I would like to know why the tag “DURATION” in Matroska files (.mkv) is
>>>>>> a necessity? Even mkvmerge lets the choice to use it or not with
>>>>>> “--enable-durations”, in addition it is written “Write durations for all
>>>>>> blocks. This will increase file size and does not offer any additional
>>>>>> value for players at the moment.” (source
>>>>>> https://mkvtoolnix.download/doc/mkvmerge.html#d4e535).
>>>>>>
>>>>>> Possibly linked to
>>>>>> http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=31852540d4fba0c4e8a16d0b3ddff08fc98e48fd
>>>>> As far as I'm aware, the linked commit does not do the same thing as
>>>>> the mkvmerge option you pointed out.
>>>> Yes that is why I wrote “possibly”, also because this commit is the one
>>>> which adds the tag “DURATION” as a necessity, but a necessity that no
>>>> software seems to use and it is not even a standard in the Matroska’s
>>>> documentation if I am not mistaken. So the fact that it is a necessity
>>>> and not a choice is the main problem.
>>> Who says it's a necessity or standard? It's just what mkvmerge does.
>>> Since the patch is by google, I assume google has some use for it
>>> (there might also be a discussion about it on the ML).
>> Sorry for the bad word “necessity”, it is better with “imposed”. Could
>> you let the choice to the user like mkvmerge with
>> “--disable-track-statistics-tags”?
> We could add a private option to the ffmpeg matroska muxer to disable
> writing this tag, and we could even switch that option off by default
> (so the tag isn't written unless the user explicitly requests it). Feel
> free to propose a patch.

I do not have the capacity for the moment to write patches for such a 
software but what you have written is exactly what I would like.

I can create a bug report if needed.