It is a good tool, but for me it only trims from the keyframes. To trim precisely, it has to re-encode, which, unfortunately, does not work on my machine for some reason. So, I just stick to ffmpeg cli.
I suppose that makes sense given that information is encoded as a series of key frames interspersed by 'I-frames" that simply encode the delta to the previous key-frame when using most compressed video algorithms. So cutting in-between key-frames doesn’t really make sense since the I-frame would no longer have anything to reference it’s delta to.
This has always bothered me, I suspect it’s the same underlying reason most video players can’t do reverse frame-by-frame. But Quicktime allowed it twenty years ago, so it’s possible. I suppose you’d have to actually decode the entire keyframe interval and use the resulting frames as new “baked-in” keyframes so to say. I suppose that’s more or less what djv and other frame checkers do under the hood. But I don’t know what I’m talking about so…
It is a good tool, but for me it only trims from the keyframes. To trim precisely, it has to re-encode, which, unfortunately, does not work on my machine for some reason. So, I just stick to
ffmpegcli.I suppose that makes sense given that information is encoded as a series of key frames interspersed by 'I-frames" that simply encode the delta to the previous key-frame when using most compressed video algorithms. So cutting in-between key-frames doesn’t really make sense since the I-frame would no longer have anything to reference it’s delta to.
Except if it’s lossless so there’s no harm in reencoding to accurately clip files
You’re confusing cause and effect. It’s lossless because it cuts at keyframes and does not re-encode.
If it did what you’re suggesting it wouldn’t be lossless anymore.
I think they were talking about a special kind of media file, that is not compressed but instead stored losslessly. I think H264 can do that too.
Lossless codecs can be decoded and reencoded without effect
LosslessCut doesn’t only use lossless codecs. It losslessly cuts video files encoded in lossy codecs.
This has always bothered me, I suspect it’s the same underlying reason most video players can’t do reverse frame-by-frame. But Quicktime allowed it twenty years ago, so it’s possible. I suppose you’d have to actually decode the entire keyframe interval and use the resulting frames as new “baked-in” keyframes so to say. I suppose that’s more or less what djv and other frame checkers do under the hood. But I don’t know what I’m talking about so…
That’s due to the source codec using keyframes, you can only cut without re-encode on those specific points.
They allow re-encoding, but that is in experimental state. It never works for me.