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Wol schrieb am 22.12.21 um 19:45: |
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> What is an i-frame? As I understood it, typically when you had a scene |
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> change, a frame was written in full, then subsequent frames were stored |
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> as diffs. Is that what an i-frame is? |
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Wikipedia [1] to the help. |
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> In which case, surely it can't be that tricky to delete a block without |
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> having to decode/encode more than a few frames? |
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Encoding only the affected region is tricky because you need to use the |
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same codec parameters (encoding profile, resolution, colour space, FPS, |
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bit depth, bitrate, and possibly more parameters which are also codec |
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dependent) like the rest of the unaffected portion of the video to be |
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able to concatenate it again afterwards with the rest of the video. Also |
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it is tricky to keep video an audio in sync when having a lot of cut |
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points. Probably there are other issues depending on the required |
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codecs. So making it work for every codec even only for the popular ones |
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might be a lot of work. |
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TTCut can do "smart cutting" by encoding only the affected GOP [2]. |
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However it only works for Mpeg2 Video and Mpeg2 Audio or Dolby AC-3 |
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Audio. I have not tested it but VidCutter [3] should also be capable of |
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doing so and as I see there is no restriction on the codecs. They are |
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the only ones I am aware of supporting this feature and they are |
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packaged for Gentoo. |
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[1] https://en.wikipedia.org/wiki/Video_compression_picture_types |
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[2] https://en.wikipedia.org/wiki/Group_of_pictures |
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[3] https://github.com/ozmartian/vidcutter |
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-- |
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Regards |
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Daniel |
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