[FFmpeg-devel] [PATCH] avfilter: add unpremultiply filter

[Paul B Mahol]

On 8/1/17, Tobias Rapp <t.rapp at noa-archive.com> wrote:
> On 01.08.2017 13:03, Paul B Mahol wrote:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>>  doc/filters.texi             |  13 ++
>>  libavfilter/Makefile         |   1 +
>>  libavfilter/allfilters.c     |   1 +
>>  libavfilter/vf_premultiply.c | 307
>> ++++++++++++++++++++++++++++++++++++-------
>>  4 files changed, 277 insertions(+), 45 deletions(-)
>>
>> diff --git a/doc/filters.texi b/doc/filters.texi
>> index 4089135..a50696a 100644
>> --- a/doc/filters.texi
>> +++ b/doc/filters.texi
>> @@ -14532,6 +14532,19 @@ ffmpeg -i INPUT -vf trim=duration=1
>>
>>  @end itemize
>>
>> + at section unpremultiply
>> +Apply alpha unpremultiply effect to input video stream using first plane
>> +of second stream as alpha.
>> +
>> +Both streams must have same dimensions and same pixel format.
>> +
>> +The filter accepts the following option:
>> +
>> + at table @option
>> + at item planes
>> +Set which planes will be processed, unprocessed planes will be copied.
>> +By default value 0xf, all planes will be processed.
>> + at end table
>
> IMHO using a flags-like string "planes=rgb" would be more user-friendly
> than a bitmask. At least the documentation should tell which bit refers
> to what channel.

It is directly related to pixel format.