[FFmpeg-devel] [PATCH] avfilter/f_loop: do not loop if loop size is 0

[Marton Balint]

On Sun, 19 May 2019, Paul B Mahol wrote:

> On 5/19/19, Marton Balint <cus at passwd.hu> wrote:
>>
>>
>> On Sun, 19 May 2019, Paul B Mahol wrote:
>>
>>> On 5/19/19, Marton Balint <cus at passwd.hu> wrote:
>>>> Fixes infinte loop with -vf loop=loop=1.
>>>>
>>>> Possible regression since ef1aadffc785b48ed62c45d954289e754f43ef46.
>>>>
>>>> Signed-off-by: Marton Balint <cus at passwd.hu>
>>>> ---
>>>>  libavfilter/f_loop.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/libavfilter/f_loop.c b/libavfilter/f_loop.c
>>>> index d9d55f9837..3da753dd1e 100644
>>>> --- a/libavfilter/f_loop.c
>>>> +++ b/libavfilter/f_loop.c
>>>> @@ -343,7 +343,7 @@ static int activate(AVFilterContext *ctx)
>>>>
>>>>      FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
>>>>
>>>> -    if (!s->eof && (s->nb_frames < s->size || !s->loop)) {
>>>> +    if (!s->eof && (s->nb_frames < s->size || !s->loop || !s->size)) {
>>>>          ret = ff_inlink_consume_frame(inlink, &frame);
>>>>          if (ret < 0)
>>>>              return ret;
>>>> --
>>>> 2.16.4
>>>>
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>>>
>>> I think better fix is to change default and minimal allowed loop size to
>>> 1.
>>> Does that sounds ok to you?
>>
>> Well, looping the whole length of the input would be more intuitive to me
>> as the default.
>
> That would require infinite memory.

So as the reverse filter. As long as it is properly documented that the 
looped stuff is kept in memory so the user should not use this for long 
clips, then I think it is fine.

Regards,
Marton