On Mon, May 25, 2009 at 5:11 AM, Oliver Seitz <info@xxxxxxx> wrote: >> Hi dear all. I know there is a function to step forward by one single >> frame, by pressing >> . in mplayer. But I did not find the reverse function to step >> backforward. Is there >> this function in mplayer? Thank you. > > No, it's not. It is not that easy. I'm not a developer, but my thoughts > about it are as follows: > > Video files consist of intra-frames and inter-frames. Intra-frames contain > all the neccessary data for one single frame and can be decoded easily. > Inter-frames only contain the differences of the new frame in respect of > the frame that was just displayed last. So, if you're stepping back to an > intra-frame, you could do all the calculation backwards which looks like a > lot of code to be possibly written. Or you could search backwards to the > last intra-frame and do all the calculations as normal until you reach the > frame you desire. That looks like a lot of system load for a little > effect. > > Then video files are usually designed to be read from start to end. There > are means implemented to help the player program always easily find the > start of the next frame in the stream. There is no help available within > the file to assist the player program finding the *previous* frame. That > might be another problem. > > Those are some of the difficulties I suspect to arise. > > But, that question is rising frequently these days. Perhaps some of the > developers will have a look at it... > > Greets, > Kiste > > _______________________________________________ > MPlayer-users mailing list > MPlayer-users@xxxxxxxxxxxx > https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users > Dear Oliver: Thank you very much for your explanation. That is very reasonable. And, for recent such questions I think I know part of the reason.... There are some video players on Windows claiming they have such function and it seems some users are pretty satisfied with it... Though I doubt they can really "go back one frame".... maybe they just go back for a very short time... Thank you! _______________________________________________ MPlayer-users mailing list MPlayer-users@xxxxxxxxxxxx https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users
