Ffmpeg generates higher quality images for encoding MJPEG

Question

I have a bunch of mov / H.264 files that I would like to encode in mov / MJPEG. However, I get very poor performance. Here is what I tried:

ffmpeg -i a.mov -an -crf 11 -preset slower -pix_fmt yuv420p -vcodec mjpeg -f mov -y b.mov 

For H.264 encoding, the -crf and -preset generate higher quality. But this does not work for MJPEG.

Answer 1

Use -q:v to control (M) JPEG quality

The effective range is a linear scale from 2 to 31, and a lower value will result in higher product quality.

Examples

Make the MJPEG video in the MOV container:

 ffmpeg -i input.mov -c:v mjpeg -q:v 3 -an output.mov 

Output a series of JPG images:

 ffmpeg -i input.mov -q:v 2 images_%04d.jpg 

Files will be called images_0001.jpg , images_0002.jpg , images_0003.jpg , etc.

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Private options

For H.264 encoding, -crf and -preset generate higher quality. But this does not seem to work for MJPEG.

The MJPEG encoder does not use -crf and -preset ; these are "private" options for some encoders such as libx264, libx265 and libvpx. You can see private options, such as: ffmpeg -h encoder=mjpeg .