ffmpeg-quality-metrics VS lossless-cut

Have you seen ffmpeg-quality-metrics? I went with the docker option. I figured that would keep it simple with ffmpeg versions/whatever.

I'm not good at computers, so I love ffmpeg-quality-metrics. I use the docker version because I didn't want to fight with dependencies.

There are even tools that can compare the quality for us, like ffmpeg-quality-metrics can give a VMAF score as used by Netflix for the visual quality difference.

You can at least test the quality difference between two encodes with something like ffmpeg-quality-metrics. If it has a high VMAF score and saved a bunch of space for something that doesn't need to be perfect, then I consider it fine.

ffmpeg-quality-metrics is nice for comparing quality between copies. Better than squinting at pixels IMO.

If you're re-encoding video then ffmpeg-quality-metrics is a great tool IMO. Can give you a scale from 0-100 of how similar it appears based on SSIM or VMAF. If I get a VMAF in the high 90's, like 95+, then I know the encode is decent and if it saved significant space (if that's the goal?) then it's a keeper.

It's working. I found this [model](https://github.com/slhck/ffmpeg-quality-metrics/blob/master/ffmpeg_quality_metrics/vmaf_models/vmaf_v0.6.1neg.json) with the help of u/Felixkruemel and I specified the vmaf path in av1an using `--vmaf-path=path to the/vmaf/model.json"`

Then, after the encode, if you want to compare original vs encoded quality there's ffmpeg-quality-metrics which makes it easy to get VMAF & SSIM scores between the two.

ffmpeg-quality-metrics is a good tool to compare before & after encodes. It can easily calculate VMAF & SSIM scores. If I understand it correctly (I might not), then anything in the high 90s for VMAF is considered hard-pressed to be able to tell. Sometimes it hits 100, which makes me fairly confident about those encodes.

idk. When I did a re-encode with CRF 23 and preset 'veryslow' it went down to 2,236 kb/s. When I do a VMAF and SSIM test with ffmpeg-quality-metrics I was getting decent scores. It takes the file size down to 2.1GB. So my guess is they either set a significantly lower CRF or set a manual bitrate and aimed for the moon.

For lossless cut, there's the LosslessCut [1] app, which even has an experimental but mostly working version of a "smart cut" feature [2] (aka. only re-encode the minimal mandatory amount of frames if you trim at a point between 2 key frames)

[1]: https://github.com/mifi/lossless-cut

[2]: https://github.com/mifi/lossless-cut/issues/126

> thought I cropped/edited a video, it is still there in full length and resolution

It's been possible to create a clip from a video file that merely changes what parts of the video are displayed without effecting the data in the original since the Classic Mac OS days.

If you want to completely remove unwanted portions of a video to reduce the size without a loss of quality, there are many options. LosslessCut is one option that is both free and open source.

https://github.com/mifi/lossless-cut

LosslessCut

Lossless Cut is probably the simplest way to cut out parts of a video without having to re-encode it or use an online service. It is open source, free and available for all platforms. It is in essence a frontend for FFMPEG and cuts without re-encoding, so the results are instantaneous.

Additionally I would like if possible to shorten (both to reduce dimension and to make them less boring) my videos by trimming the beginning and/or ends where often there is nothing interesting happening and possibly change the thumbnails for easier identification. Do you know of any tool that does the job with the minimum quality degradation possible? Many years ago I've tried with some videos and a tool I don't remember anymore, ending up with a bunch of corrupted files :( I've found https://github.com/mifi/lossless-cut for the point above.. need to try it. please let me know what experience you have with it.

Lossless Cut would probably be a better choice for this. Will let you cut out the commercials without having to re-encode the video.

>Of course, you could only re-encode only the GoPs that get broken while keeping the rest intact, and I guess this would be better and a lot faster than re-encoding everything. I don't know if any application tries to do this.

LosslessCut does have experimental support for this partial re-encode called "smart cut" [1]. Since it's using ffmpeg internally, the challenge become how to instruct ffmpeg to do this[2]?

[1]: https://github.com/mifi/lossless-cut/issues/126