Which pixel format for web mp4 video?

Question

I have to create video in mp4 format, and it seems that I can encode it with different pixel formats like yuv420p, yuv422p, yuvj422p.

Answer 1

Use yuv420p

You can use the -vf format=yuv420p (or the alias -pix_fmt yuv420p) output option to make sure your output is YUV 4:2:0.

Example

ffmpeg -i input -c:v libx264 -crf 23 -preset medium -vf format=yuv420p -c:a copy -movflags +faststart output.mp4

• For web video the -movflags +faststart option is also recommended.
• The audio is being stream copied (re-muxed) in this example instead of being re-encoded. Useful if the input is already AAC.
• See FFmpeg Wiki: H.264 & H.265 for more info on the encoder specific settings (-crf and -preset).

Determining the pixel format of a video

You can check the pixel format of a video with ffprobe:

$ ffprobe -loglevel error -show_entries stream=pix_fmt -of csv=p=0 input.mp4
yuv420p