[FFmpeg-devel] [PATCH] matroskadec: Improve TTA duration calculation

[Paul B Mahol]

On 8/17/13, James Almer <jamrial at gmail.com> wrote:
> On 17/08/13 3:30 PM, Paul B Mahol wrote:
>> On 8/17/13, James Almer <jamrial at gmail.com> wrote:
>>> On 17/08/13 6:48 AM, Paul B Mahol wrote:
>>>> On 8/16/13, James Almer <jamrial at gmail.com> wrote:
>>>>> On 16/08/13 5:21 PM, Paul B Mahol wrote:
>>>>>> On 8/16/13, James Almer <jamrial at gmail.com> wrote:
>>>>>>> On 16/08/13 7:24 AM, Paul B Mahol wrote:
>>>>>>>> On 8/15/13, James Almer <jamrial at gmail.com> wrote:
>>>>>>>>> -            avio_wl32(&b, matroska->ctx->duration *
>>>>>>>>> track->audio.out_samplerate);
>>>>>>>>> +            avio_wl32(&b, av_rescale(matroska->ctx->duration,
>>>>>>>>> track->audio.out_samplerate, AV_TIME_BASE));
>>>>>>>>
>>>>>>>> Isn't time base variable thing that can be changed by muxer?
>>>>>>>>
>>>>>>>> Perhaps this could be used when muxing tta files to make sure
>>>>>>>> last packet can always decode.
>>>>>>>
>>>>>>> Our muxer already uses 1000000 (aka AV_TIME_BASE) as timescale for
>>>>>>> every
>>>>>>> file.
>>>>>>
>>>>>> But this patch does not use time base as used in file, but hardcode
>>>>>> it,
>>>>>
>>>>> It's using matroska->ctx->duration, which is calculated using the
>>>>> duration
>>>>> and the timescale of the stream as stored in the file (line 1546).
>>>>
>>>> But could it use track duration which is set in track time base units?
>>>
>>> So you mean doing "av_rescale((matroska->duration *
>>> matroska->time_scale),
>>> track->audio.out_samplerate, AV_TIME_BASE * 1000)"?
>>> I guess that might be a tad more accurate depending on the file.
>>
>> I do not mean anything. But isn't time scale & duration different for
>> each track?
>
> I guess so, but what difference does that make?

audio is in track and each track can have different duration?
Thus global one can be for anything else.

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