[spinaltap]

Question: this tool offered start-time and end-time, but no toggle about "accurate seek"? I've always been confused about the `-noaccurate_seek` flag (when cutting clips with `-c copy`).

I use this flag because I don't need accurate seek, but sometimes it works, sometimes it doesn't. When it doesn't work, there will be a few seconds of frozen image at the beginning of the cut. Don't know how to solve it.

[ThatPlayer]

Isn't that only relevant because you're using -c copy? Without transcoding, ffmpeg will just copy the stream from that start-time. But because video codecs store data as incremental updates to a keyframe, without transcoding, those first few seconds will be useless data. -noaccurate_seek looks for the keyframe so you do not have that useless data.

Proper terms are i-frame and p-frame. https://en.wikipedia.org/wiki/Video_compression_picture_type...

Though according to the ffmpeg docs on -ss, it should be doing noaccurate_seeks if you're doing stream copy.

Also I'm unsure about this, but I think the audio stream can be cut at a different location than the video stream, leading to the frozen frame, and different video players seem to handle it differently. I've got a clip I've made, with transcoded video stream but copied audio stream, that is 1:06 on Firefox with the extra audio at the beginning, but 1:03 on VLC, MPC, Chrome, and desynced in Edge. Extracting the audio with ffmpeg again gives a time of 1:04.02 compared to a video stream of 1:03.