IMX Scaler / CSC m2m driver.

[Carlos Rafael Giani]

On 03/23/2015 01:42 PM, Nicolas Dufresne wrote:
> Le lundi 23 mars 2015 à 11:39 +0100, Philipp Zabel a écrit :
>> This is a hardware limintation. The videodec output is 1920x1088 with
>> 8
>> lines of garbage.
>> The only way to scale that down to 1920x1080 for the IPU IC is to use
>> the 2:1 downscaler (to 1920x544) and then use the bilinear upscaler to
>> scale it back up to 1920x1080.
>>
>> The decoder output should be cropped to 1920x1080 when feeding it into
>> the scaler/csc.
> Note that the decoder should already present caps as being 1920x1080 and
> hide the padding through VideoMeta stride and offset array. It is more
> likely that the converter patch that has been applied to add scaling is
> not well tested and is leading to bugs.
>
> Nicolas
>
>
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This is precisely how gstreamer-imx also does it. 1920x1088 is also what 
the VPU delivers, due to its required 16-pixel alignment. I simply set 
the last 8 rows as padding rows. Works very well, as long as the sinks 
are aware of padding.