[FFmpeg-devel] [PATCH]lavf/matroskaenc: Do not write 0 duration for subtitles

[John Stebbins]

On 11/14/2017 02:18 PM, Carl Eugen Hoyos wrote:
> 2017-11-14 19:02 GMT+01:00 Jerome Martinez <jerome at mediaarea.net>:
>> On 12/11/2017 03:12, Carl Eugen Hoyos wrote:
>>> -            put_ebml_uint(pb, MATROSKA_ID_BLOCKDURATION, duration);
>>> +            if (duration > 0)
>>> +                put_ebml_uint(pb, MATROSKA_ID_BLOCKDURATION, duration);
>>
>> In that case, the duration of the block is DefaultDuration (if it exists),
>> completely different.
>> Is it intended to say that a duration of 0 at this place means that the
>> block has the default block duration if it exists?
>>
>> What is the use case for a duration of 0?
> Iirc, pgs subtitles send an empty "frame" to reset / remove the
> subtitle.

Correct, this is the source of these 0 duration pgs "subtitles".

>
>> (Note: the meaning of the a block duration of 0 is unclear to me, I'll ask
>> on CELLAR mailing list to clarify that)
> So maybe the issue is with mkvalidate?
>
> Carl Eugen
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-- 
John      GnuPG fingerprint: D0EC B3DB C372 D1F1 0B01  83F0 49F1 D7B2 60D4 D0F7


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