[FFmpeg-user] ffmpeg: chroma pixels are wrong when using cuvid to decode h264 stream to yuv file

[Andy Furniss]

ekin yang wrote:
> Dear expert,
> 
> 
> Currently I am trying to use ffmpeg and Nvidia GPU card to decoding
> h264 stream to yuv file.  There are no errors during the decoding
> process. But I find the yuv file I got is not exactly correct. It
> seems the luma pixels are correct but chroma pixels are wrong.
> 
> GPU: Nvidia telsa m40
> 
> driver: 375.26
> 
> cuda toolkit:8.0
> 
> ffmpeg version: 3.3.2
> 
> Decoding command line : ./ffmpeg -c:v h264_cuvid -i inputfile.264
> output.yuv
> 
> 
> [cid:c4bbc81f-3431-4c37-ba55-4d90cc266239]
> 
> 
> 
> Can anybody help out this problem? I am so much appreciated.

You should really post full console output from the command.

yuv is ambiguous = there are many different layouts and you need to know
which one to display/convert it correctly. ffmpeg output should say
what it is.

If you want a certain format eg. yuv420p then ffmpeg can convert for
you, use -pix_fmt yuv420p with your command.

I guess that cuvid is producing nv12 so you could just try telling
what you use to process/convert the yuv that's what it is.