KEY-Frame vs Frame

[Hugo]

Setting a START and END Marker, the position can be selected using the Frame-Buttons and KEY-Frame-Buttons.

However, markers set by the Frame-Buttons, set different from KEY-Frame positions, are NOT SAVED as such. The markers skip to the surrounding KEY-Frame positions. In case of the Start-Marker, to the Key-Frame position before.

Does anyone know if this is a program bug, or if I'm the problem not knowing the program functions.

In case of the last: what to do

PS:
All program settings are standaard.

[eumagga0x2a]

markers set by the Frame-Buttons, set different from KEY-Frame positions, are NOT SAVED as such. The markers skip to the surrounding KEY-Frame positions. In case of the Start-Marker, to the Key-Frame position before.

When saving in copy mode, only the start of a selection is automatically and silently corrected to a valid position (i.e. to the closest previous keyframe). Cut points resulting from edit operations like copy & paste or delete are checked for being at keyframes and a stern warning issued if they are not.

This is a feature, not a bug. In copy mode, the start of each video segment must be at a keyframe for the video to have a chance to be playable without major defects. This limitation is fundamental, i.e. dictated by the nature of video compression.

To be able to cut at any frame, video needs to be re-encoded.

[butterw]

In Copy mode start-frame always has to be a keyframe. This is a requirement for cutting without re-encoding. 

[Hugo]

Thanks very mucch.

Ok, next step: RE-ENCODING, where to do this ?

Sorry, I.m all new to video adjusting.

I think this is done by setting under VIDEO OUPTUT and AUDIO OUTPUT. Standard this is set to COPY. ANd that seems to be my problem. So probably for VIDEO OUTPUT this must be set to another setting.

If Yes: which one ?

Or maybe, RE-ENCODING is done otherwise. How ?

[eumagga0x2a]

I think this is done by setting under VIDEO OUPTUT and AUDIO OUTPUT. Standard this is set to COPY. ANd that seems to be my problem. So probably for VIDEO OUTPUT this must be set to another setting.

Yes, right.

f Yes: which one ?

This entirely depends on your needs, i.e. what kind of device with what capabilities will handle the produced video stream, and the properties of the source video.

If you want some guidance here, you would need to provide info, starting with properties of the source video.

[Hugo]

Tanx again.Serious.

I record movies that are streamed, resulting in MP4 files. Than I just want to cut some of the begin-end-frames, using frames instead key-frames, as precise as possible.

At this moment the COPY setting makes MKV files which I can display on TV, computer and gsm. And that is also what I want to do with it: watching the movies at any screen. Mostly using VLC, at the computer, or the software on the TV with the movie on a USB stick in the back of the TV.

Using the COPY setting is very easy AND FAST to do. Decoding, cutting and saving takes about 30 seconds per movie. And I have a lot of movies to work on.

Besides working FAST, I also prefer quality. However going from MP4 to MKV gives the same file size. By which I think quality keeps the same. 1,5 hour movie is about 2 GB. That is ok to me.

[butterw]

- With COPY: fast and lossless, but any cuts will start on a Keyframe.

- With x264 re-encode: takes time, quality will be degraded or filesize will increase. But you can cut on any frame and you can add filters, crop/resize, etc.
- ! you need to determine your Encoding setting, ex: x264-high --slow crf23). Test on a file a couple of minutes long, to see if speed and quality are OK otherwise adjust settings.

- The output container can be mp4 or mkv in both cases.