[FFmpeg-user] 422 to 444 Upsampling Testbed

Paul B Mahol onemda at gmail.com
Mon Apr 29 22:13:28 CEST 2013


On 4/29/13, Vincent Olivier <vincent at up4.com> wrote:
> On 2013-04-29, at 3:58 AM, Paul B Mahol <onemda at gmail.com> wrote:
>
>> Splitting yuv into planes of gray is supported for rawvideo codec only.
>> Filter could be added that export single or all planes into gray
>> image(s).
>
>
> But with this command, I actually manage to output a file with the
> horizontally aligned images.
>
> My problems are that:
>
> I would like to have separate files (all things considered, I can very well
> do that in many FFMPEG calls, it doesn't have to be one command).
> the chroma images are not grayscale
>
> And I think I have the command for the luma image :
>
> ffmpeg -i input.mxf -filter_complex "lutyuv=u=128:v=128" -vframes 1 y.png
>
> And is says it's a "rgb24" image where I want it to be a "gray16"

I already told you to use image muxer with raw video codec and extension .y to
do what you seek.

Than you would neeed another command to encoder raw files to .png

>
> Plus, I don't understand the lutyuv. What does the 128 mean?

There is documentation, what is not clear about it?

>
> And can I do the same thing for the chroma channels?

Not with lut filter. Your only solution for now is to use image muxer
with .y extension and raw video codec
(its set automaticaly if not set to anything).

I could write filter which would do same and would work like this:

ffmpeg -i input.mxf -filter_complex separateplanes=all -o y%d.png -o
u%d.png -o v%d.png

All outputs would be in gray colorspace.


>
> Thanks!!!!
>
> Vincent
>
>
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