[FFmpeg-user] remap filter gives only black and white output

[Shaji]

Hello,

I am using the latest ffmpeg version. I am facing the same issue as discussed in the thread:
 
https://ffmpeg.org/pipermail/ffmpeg-user/2017-November/037971.html

That is remapping produce black and white output. If I use the workaround of using the format conversion then the processing slows down very drastically.

One more thing to add is if I use yuv444p then the output is encoded coloured.

Command producing black and white:

Fps: 29

ffmpeg -y -stream_loop -1 -i silence.mp3 -r 30 -i rtmp://172.104.245.86/live/test  -i sample2160_x.pgm -i sample2160_y.pgm -lavfi "remap" -vcodec h264_nvenc -pix_fmt yuv420p -b:v 10000k -f flv rtmp:xxxx

Command producing colored output:

Fps: 20

ffmpeg -y -stream_loop -1 -i silence.mp3 -r 30 -i rtmp://172.104.245.86/live/test -i sample2160_x.pgm -i sample2160_y.pgm -lavfi "remap" -vcodec h264_nvenc -pix_fmt yuv444p -b:v 10000k -f flv rtmp:xxxx

Fps: 12

ffmpeg -y -stream_loop -1 -i silence.mp3 -r 30 -i rtmp://172.104.245.86/live/test  -i sample2160_x.pgm -i sample2160_y.pgm -lavfi " format=pix_fmts=rgb24,remap" -vcodec h264_nvenc -pix_fmt yuv420p -b:v 10000k -f flv rtmp:xxxxx

Another interesting observation is that if I use ffmpeg version 3.3.2 then below mentioned command gives 
20 fps with colored output

ffmpeg -y -stream_loop -1 -i silence.mp3 -r 30 -i rtmp://172.104.245.86/live/test  -i sample2160_x.pgm -i sample2160_y.pgm -lavfi "remap" -vcodec h264_nvenc -pix_fmt yuv420p -b:v 10000k -f flv rtmp:xxxx
 

Can you please tell me if this bug can be rectified as we want to achieve colored 29fps with this setup.

Thank you.

Best regards,
Shaji Baig