[FFmpeg-devel] [PATCH 1/5] avfilter/af_afade: fix crossfade duration maximum value

[Marton Balint]

On Mon, 1 Oct 2018, Paul B Mahol wrote:

> On 10/1/18, Marton Balint <cus at passwd.hu> wrote:
>>
>>
>> On Mon, 1 Oct 2018, Paul B Mahol wrote:
>>
>>> On 10/1/18, Marton Balint <cus at passwd.hu> wrote:
>>>>
>>>>
>>>> On Mon, 1 Oct 2018, Paul B Mahol wrote:
>>>>
>>>>> On 9/30/18, Marton Balint <cus at passwd.hu> wrote:
>>>>>> Signed-off-by: Marton Balint <cus at passwd.hu>
>>>>>> ---
>>>>>>  libavfilter/af_afade.c | 4 ++--
>>>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>>
>>>>>
>>>>> Why?
>>>>>
>>>>> Value is too big.
>>>>
>>>> AV_OPT_TYPE_DURATION is microsecond precision, therefore 60 is 60 usecs.
>>>> Probably you meant 60 seconds as limit. That is what the patch fixes.
>>>
>>> I do not think so. Duration is interpreted as seconds, look how
>>> variable is used in code.
>>
>> As far as I see duration is rescaled from AV_TIME_BASE (microseconds) to
>> sample_rate time base:
>>
>> if (s->duration)
>>       s->nb_samples = av_rescale(s->duration, outlink->sample_rate,
>> AV_TIME_BASE);
>>
>> Duration is parsed as seconds (can be fractional as well), but internally
>> it is stored as microseconds (int64). Another example is the f_realtime
>> filter where the sleep time limit default according to the documentation
>> is 2 seconds and it is expressed as 2000000 in the code.
>
> Yes, and current patch is wrong. Simply exceding max value is not proper fix.

What is the proper fix then?

Regards,
Marton