[Kdenlive-devel] Color spaces and MLT

[Dan Dennedy]

On Wed, Jul 21, 2010 at 12:16 PM, Simon Eugster <simon.eu at gmail.com> wrote:
> 2010/7/21 Dan Dennedy <dan at dennedy.org>:
>> On Wed, Jul 21, 2010 at 10:51 AM, Simon Eugster <simon.eu at gmail.com> wrote:
>>> Dear friends,
>>>
>>> I've just added an RGB parade to kdenlive. While testing I found
>>> something interesting: Although I'm painting on a rect with height 256
>>> (as atm we're dealing with 8 bits per channel only) and scaling the
>>> parade afterwards to the target height, I got kind of scanlines.
>>> Compare these two images:
>>> http://granjow.net/uploads/kdenlive/kdenlive-mlt-rgbparade-noeffect.png
>>> http://granjow.net/uploads/kdenlive/kdenlive-mlt-rgbparade-witheffect.png
>>> With the MLT effect there are scanlines, without it there are none.
>>>
>>> This is quite interesting, as this visualizes how color information
>>> gets lost when converting between different color spaces (according to
>>> [1], MLT is using YUV422, the input image is RGB).
>>
>> It does not operate exclusively in YUV422. The color/image-format
>> conversion implementation depends on your build and your version of
>> libswscale (>= 0.7.2) whether MLT uses libswscale or inbuilt routines.
>> Maybe the problem is in the composite transition.
>
> libswscale is at 0..6 here in debian sid.

I do not believe that is correct. Maybe you are looking at a package
version. What does 'ffmpeg -version' show as the libswscale version?
-- 
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