What's the different between Smart cut and Normal cut?

[Honghe]

lossless-cut is a great tool, but I am a little confused.

In the Export config, it says:

• "Smart cut", This experimental feature will re-encode the part of the video from the cutpoint until the next keyframe in order to attempt to make a 100% accurate cut. Only works on some files. I've had success with some h264 files, and only a few h265 files. See more here: 😍 Implement "smart cut" #126
• "keyframe cut", we will cut at the nearest keyframe before the desired start cutpoint. This is recommended for most files.
• "Normal cut" you may have to manually set the cutpoint a few frames before the next keyframe to achieve a precise cut.

So, What's the different between Smart cut and Normal cut?

[Hrxn]

I think it's already explained pretty well there. What exactly do you want to know more about?

Smart Cut simply means that you are not bound by the files' keyframes, you can cut exactly where you want, although it means that some frames will have to be encoded again.

Seriously, it's best to see when you try this for yourself. Find yourself a "bad" video file, which means very few keyframes, and then cut a segment anywhere you like in Normal Cut mode. The actual cut point will always snap to the nearest keyframe, and in a bad file, this may be so far off that it is very noticeable.

[Honghe]

I think it's already explained pretty well there. What exactly do you want to know more about?

Smart Cut simply means that you are not bound by the files' keyframes, you can cut exactly where you want, although it means that some frames will have to be encoded again.

Seriously, it's best to see when you try this for yourself. Find yourself a "bad" video file, which means very few keyframes, and then cut a segment anywhere you like in Normal Cut mode. The actual cut point will always snap to the nearest keyframe, and in a bad file, this may be so far off that it is very noticeable.

Thanks, I have two questions:

• Are both Smart cut and Normal cut 100% accurate cut?
• Does Normal cut re-encode the whole cut segment or only re-encode the part of the video from the cutpoint until the next keyframe?

[Honghe]

Seriously ... and then cut a segment anywhere you like in Normal Cut mode. The actual cut point will always snap to the nearest keyframe, and in a bad file, this may be so far off that it is very noticeable.

This feature looks like Keyframe cut.

[Hrxn]

Thanks, I have two questions:

• Are both Smart cut and Normal cut 100% accurate cut?

Yes, basically. They are accurate as in respecting your chosen cut-point, but since in Normal Cut nothing gets re-encoded you might have a short empty segment. Depending on the file, only smart cut might be 100% time accurate.

• Does Normal cut re-encode the whole cut segment or only re-encode the part of the video from the cutpoint until the next keyframe?

No, nothing gets re-encoded.
Certainly not an entire cut segment, because it wouldn't be lossless anymore. Normal cut also does not re-encode the overlapping part (as in, the difference between selected cutpoint and keyframe), it simply forces ffmpeg to seek with accurate time (if the format allows, it's usually never really accurate) for cutting. Which might work as you want, or not, I don't think this can be reliably predicted beforehand, because it depends on the encoding of the file you cut. You can only try it out.

The actual cut point will always snap to the nearest keyframe.

This feature looks like Keyframe cut.

Yes, this is how Keyframe cut works, and why it is called that way..

Edit This is what I mean with Normal cut in my comment there, I should have been more clear. But Normal cut is usually Keyframe cut because the Keyframe cut option is enabled by default, if I'm not mistaken.