[FFmpeg-devel] [PATCH] extractplanes filter

[Paul B Mahol]

On 5/3/13, Paul B Mahol <onemda at gmail.com> wrote:
> On 5/3/13, Nicolas George <nicolas.george at normalesup.org> wrote:
>> Le tridi 13 floreal, an CCXXI, Paul B Mahol a ecrit :
>>> I wonder how format renegotiation works. I would like to pick 16bit gray
>>> with right endianess depending on input format - if its 16 bit at all
>>> otherwise just pick 8bit one.
>>
>> That would be useful in this situation indeed.
>>
>> The basic principle is this: query_formats() sets the formats it can, and
>> if
>> it could not set everything it returns EAGAIN, and will be called again
>> later, hopefully when more information is available.
>>
>> In this situation, I believe the correct flow is this:
>>
>>     if input formats are not set
>>         set input formats to all 8 and 16 bits formats
>>     if input formats still contains several bit depths
>>         return AVERROR(EAGAIN)
>>     else
>>         set output formats to the corresponding gray format
>
> This still does not explain what input formats means. Inputs formats
> of inlink or output formats
> of inlink?
>
> I get nice forever loop if set out formats for inlink and than expect
> it to change.
>
> So its not that simple like it appeared at first.
>

I got it working somehow and pushed it.