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  1. Member
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    Mar 2011
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    Hello

    This is indeed a newbie question.

    I often need to slice a video and usually use AviDemux for that. Videos are usually compressed in h264 + AAC and packed into an MP4 container.

    Problem is, it's pretty common to have to start splitting on an "intermediate" frame, ie. not a keyframe… which requires re-encoding the video, causing yet more loss in quality.

    So I was wondering: Is there a slicer (for Windows) that can generate a new keyframe by taking the intermediate frame and the last keyframe, so that no re-encoding is necessary?

    Thank you.
    Last edited by yetanotherlogin; 12th Nov 2014 at 08:03.
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  2. Member
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    Even keyframes aren't losslessly encoded, so the re-encoded keyframe would be of a lower quality than the original, since any frame that references it would expect it to look exactly like the original frame there may be artefacts if you don't re-encode them as well. Also a frame may reference a frame BEFORE the new IDR frame and it would have to be re-encoded in that case as well. It's better to just re-encode the entire gop and there are programs that do that.

    https://www.videohelp.com/tools/sections/video-editors-h264-avc

    MKVCutter is free
    SolveigMM Video Splitter isn't
    There are probably others there.
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  3. Member
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    Thanks for the infos.

    So I'll just re-encode with AviDemux.
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  4. Member
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    ???

    A GOP is just the frames between one key-frame and the next, it'd take about 2 seconds to re-encode one using even the most crippling x264 settings. But fine, you do that.
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  5. Member
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    I don't know what a GOP is.

    Since FVE pretends to be able to let "you delete unwanted parts from video files without re-encoding", I gave it a try but didn't find how to make multiple selections in a video and have them split into multiple files or (ideally) a single file: Even after making selections, checking "Split by selections" and hitting "Save video", the files don't start where I made the selections. Any idea why?

    http://www.dvdvideosoft.com/guides/free-video-editor.htm
    Last edited by yetanotherlogin; 12th Nov 2014 at 06:18.
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  6. I'm a MEGA Super Moderator Baldrick's Avatar
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    Because free video editor doesn't support "smart rendering" like mkvcutter and solveigmm video splitter.
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  7. Member
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    I don't know what "smart rendering" is either.

    At this point, here's what my screen looks like, and the four files it created do not match at all the start/end selections I made
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  8. Member
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    I think free-video-editor is one of the programs that cuts on key-frames, at least I can't see anything that indicates it re-encodes the gops on the boundaries.

    VideoReDo
    Smart Cutter Ps/Ts
    MKVCutter
    SolveigMM Video Splitter
    TMPGEnc

    Are the one's that seem to "cut on any frame"
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  9. Member
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    Thanks for the infos.
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