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Old 26th September 2015, 02:53   #1  |  Link
Elegant
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Cutting on non-IDR frames

Hi, I currently have a few videos I want to trim. Naturally, I hit a point where I can't cut without damaging the rest of the current GOP. Would a "decent" solution be to remove that GOP and then re-encode that section using the same settings but trimming the frames off?

Although I have the source material, some effort was already placed on these encodes and I would rather not figure out exactly which AviSynth filters I applied to this before encoding again.

Just looking to get a few opinions. Thanks!
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Old 27th September 2015, 21:43   #2  |  Link
ajp_anton
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That's one way of doing it, yes. Or you could encode the trimmed GOP from the source and join with the rest, if you can figure out at least some of your Avisynth filters and get better quality than re-encoding encoded frames.
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Old 28th September 2015, 01:57   #3  |  Link
F J Walter
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Quote:
Originally Posted by Elegant View Post
Would a "decent" solution be to remove that GOP and then re-encode that section using the same settings but trimming the frames off?
It will work, but the short segments will be of lower visual quality and will likely be a different bitrate, because they are an extra generation of encoding away from the original so the encoder will have to try to re-encode additional artifacts.

Try it and see how bad the changes are - maybe you won't notice, maybe you can live with them, or maybe there will be too much degradation for you.

Another thing you could try is boost the quality/bitrate for those short segments to try and compensate.

This is basically how many "lossless" editing software works when it has to cut in the middle of a GOP.
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Old 28th September 2015, 15:29   #4  |  Link
Elegant
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Originally Posted by ajp_anton View Post
That's one way of doing it, yes. Or you could encode the trimmed GOP from the source and join with the rest, if you can figure out at least some of your Avisynth filters and get better quality than re-encoding encoded frames.
Now there's something I hadn't thought of. I suppose I could just run mcdaa3 (looks to be close enough) on the bluray source for the missing segments and append them all together. Same settings, so I shouldn't need different ids for each section.

Thanks!

Last edited by Elegant; 28th September 2015 at 16:25.
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