[FFmpeg-devel] [PATCH] avutil/parseutils: only accept full us duration, do not accept mss duration

[Tobias Rapp]

On 08.03.2018 00:14, Hendrik Leppkes wrote:
> On Thu, Mar 8, 2018 at 12:05 AM, Aurelien Jacobs <aurel at gnuage.org> wrote:
>> On Wed, Mar 07, 2018 at 11:45:03PM +0100, Marton Balint wrote:
>>>
>>>
>>> On Wed, 7 Mar 2018, Aurelien Jacobs wrote:
>>>
>>>> On Tue, Mar 06, 2018 at 01:02:48AM +0100, Marton Balint wrote:
>>>>> Accepting 'u' suffix for a time specification is neither intuitive nor
>>>>> consistent (now that we don't accept m).
>>>>
>>>> The 'm' SI prefix is still accepted in various time options, and the 'u'
>>>> prefix is still accepted in those options even after your patch, so you
>>>> can't really argue that this patch improve consistency.
>>>> (eg. -black_min_duration 5ms is still accepted).
>>>> So this will surprise nobody that I don't like this patch.
>>>
>>> This really is a cursed topic, I am not sure I follow, after the patch:
>>>
>>> 5ms is accepted
>>> 5us is accepted
>>> 5m is not accepted
>>> 5u is not accepted
>>
>> That is only for AV_OPT_TYPE_DURATION.
>> All other numeric options type still accept SI prefix without unit.
>> This include various time options such as black_min_duration.
>> So after the patch, for black_min_duration:
>>
>> 5m is accepted
>> 5u is accepted
>>
> 
> Because those use AV_OPT_TYPE_DOUBLE, a generic type without any
> possiblity of a unit.
> Ideally those should all be transitioned to AV_OPT_TYPE_DURATION if
> they refer to a time for consistency, and not the actual time-type
> bend to reflect some generic type. Why would we have the duration type
> if its just a copy of the double type anyway?

As a user with technical background I find it logical that 
AV_OPT_TYPE_DURATION is a superset of AV_OPT_TYPE_DOUBLE. Any 
double-formatted string is treated as a value in seconds. Additionally 
AV_OPT_TYPE_DURATION accepts HH:MM:SS formatted strings.

So I think Aurelien has a point here: Why should we enforce a unit 
suffix for AV_OPT_TYPE_DURATION and loose the superset property?

Regards,
Tobias