According to https://github.com/mpv-player/mpv/issues/4019 backward stepping for example with H264 codec is slow compared to forward stepping. Other codecs, for example mjpeg works a bit better.

For which other codecs/codec settings backward stepping is fast?


3 Answers 3


As @Mulvya says it depends greatly on the GOP size, but you can insure that stepping is easy at the expense of file size, by using an 'all-I' codec like Motion JPEG. In such codecs every frame appears whole and entire so there is no dependence on previous or subsequent frames.

  • Abbreviation info: "all-I" as in "using entirely Intraframe Coding". Opposed to Interframe Coding (IPB) where the abbreviation stands for Intra-Frame + Predicted Frame + Bi-directional predicted frame.
    – porg
    Commented Aug 17, 2021 at 16:32

I assume, you want fast codec for video editing.

In previous years here was "codecs for editing", it was DV codec (used in miniDV cameras) and mjpeg (used in some video cards/"montage" cards). This codecs was implemented in hardware and mainly used for capture, but some hardware allows playback and even adding some simple effects and transitions. Yes, video transitions was implemented in hardware. Today this hardware and tricks is obsolete. But mjpeg still used in many webcameras which connected by usb! Yes, you usually got not "raw signal" from your webcam, but compressed by jpeg.

Today you can use DNxHD/DNxHR/ProRes, but mjpeg still good for creating proxy footages.

Other intra-only codecs: JPEG2000, lossless-jpeg, MagicYUV

Great blog post about codecs and proxy-editing: https://blog.frame.io/2017/02/15/choose-the-right-codec/

If you don’t have enough storage space, or if you’re on an underpowered machine, then take the resolution down a notch. A lot of huge-budget Hollywood films were edited in 480p just a few years ago, so don’t sweat it if you need to lower your resolution from 4K down to 720P for the edit.

Also, you can specify "gop size=1" or "not use P and B frames" (it same) in almost any modern codec and get similar results. If you want REALLY FAST, I suggest to see on very old codec Cinepack - it was able playback video on even 80486 machines and you can find it today! Quality of Cinepack not perfect by today standards, but it enough for editing and preview purposes.


I fixed by uncommenting the RIGHT seek 5 and LEFT seek -5 lines in input.conf and also by adding hr-seek=yes in mpv.conf

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.