View Full Version : How to cut video frame accurate without encoding?
For Fun
4th November 2020, 16:45
How can I cut video by frame number? when I cut the video
With ffmpeg it skips to next keyframe I want to cut video with specific frame number or specific time I set how can I do this?
İs there a free program for this? Or how can I do this with ffmpeg?
manolito
4th November 2020, 16:57
If your video is MPEG2 elementary streams (DVD format) then you can use Cuttermaran. No longer maintained, but very reliable.
For other formats the only free solution I am aware of is VidCutter. But it is not very reliable. A commercial software for frame accurate cutting is Smart Cutter, it works nicely most of the time, but it costs $.
For Fun
4th November 2020, 17:19
I thank you for your reply. I will look at the programs you specified
butterw2
4th November 2020, 17:24
Without re-encoding, you can only cut on keyframes in h264/h265.
Partial re-encoding might be what you are looking for, aka "smart rendering", but AFAIK no free program does it.
SeeMoreDigital
5th November 2020, 14:52
Without re-encoding, you can only cut on keyframes in h264/h265.
Partial re-encoding might be what you are looking for, aka "smart rendering", but AFAIK no free program does it.In the past I've used VirtualDub2 to find the keyframes timecodes. And TSmuxerGUI to cut them.
It's quite a faff but it works ;)
NanoBot
5th November 2020, 15:44
What do you think about this program:
https://github.com/mifi/lossless-cut/
I did only a few tests by myself and therefore cannot decide, if it would fit your needs.
manolito
5th November 2020, 16:46
Lossless Cut is nice, but just like other free solutions it only cuts at key frames. From the readme:
Known issues & limitations
Cutting times are not accurate! Start cut time will be "rounded" to the nearest previous keyframe.
One thing which gave me acceptable results in the past:
TSDoctor (commercial, but has a 30 days trial period) has an option for AVC streams to cut not only on key frames, but also on P-frames. I did not expect good cuts from this option, but surprisingly it worked really well in most cases. Of course you cannot say that this is frame accurate, but still much better than only cutting on I-frames.
butterw2
5th November 2020, 17:04
In the past I've used VirtualDub2 to find the keyframes timecodes. And TSmuxerGUI to cut them.
It's quite a faff but it works ;)
Provided you know the encoding parameters and can replicate them, smart render could possibly be done manually with free tools (avidemux, or the ones you mention ?). It's a fair bit of trouble though ...and for less expert users may not always work. Cutting isn't so much the issue as merging.
Lossless-cut is another lossless cutter (cut sequence must start on a keyframe).
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