Wrong ffmpeg parameters for bitrate limiting

[joef42]

I think the parameters used for ffmpeg are not doing what they are expected to do. When using crf with h264 an additional -b:v parameter is ignored. According to https://trac.ffmpeg.org/wiki/Encode/H.264#ConstrainedencodingVBVmaximumbitrate for targeting a crf while still limiting the maximum bitrate -maxrate and -bufsize should be used.

Other than that this is a great webapp, exactly what I was looking for 👍 .

[joef42]

Sorry, another question/comment on ffmpeg parameters. I noticed that all thumbnails for videos have a rather bad quality, even for HD videos. I found that webp thumbnails for videos are generated with -qscale:v 4 setting. Did some manual tests and while for jpg outputs 4 seemed ok-ish, for webp the quality is not that great and the file size was much smaller on average than the generated webp thumbnails for images. I got much better results with -qscale:v 50 with a size more in the range of thumbnails for images.

Could this be changed? I can also create a PR if it helps.