Splitting with MKVmerge

[carlmart]

As I am not too familiar with how you can use MKVmerge to split a large file in two pieces, I wonder who might tell me some tips on how to handle it.

What I have learnt till now is that it's a lossy format basically designed for the final stage: viewing. So there's not too much you can do.

Splitting is something it can do, though not too accurately. Today I took a large file and picked a neutral spot where I could cut it.

The resultant files behave like this: part 1 plays fine, apparently with no problems at all; part 2 is a different thing. There seem to be some problems, that reveal when I try to use MPC to play it: it doesn't. Then I took the memory stick where the files are and part 2 also refused to play on my LG BD390, which plays MKV files alright.

My first idea was to demux the file and remux it again, but I am not too sure it will work.

Is there a "right" way to do a split in MKVmerge?

[redwudz]

With highly compressed formats you need to do the split on a 'keyframe' or 'I' frame or you will have problems.. Most highly compressed formats like Xvid/Divx only have keyframes every 300 frames or so, I believe H.264 is similar. That makes frame accurate editing all but impossible.

But for a simple split, just pick the nearest keyframe. Most editors, like VirtualDub, have a 'key' button for that. I haven't used MKMerge, but it should work in a similar way. The other option is to do the split where you want, then re-encode, but then you will have quality loss.

If I need to do extensive editing, I convert to a lossless format like Lagarith or HuffyUV or a low loss one like DV and every frame is a keyframe and you can cut most anywhere. Then I convert back to the desired format. This reduces quality losses, but lossless formats give you huge files to work with.

[carlmart]

I am not sure VirtualDub can handle H264 files inside the MKV package. And I would prefer to handle this with MKVmerge as it seemed to work fine in the past.

This time it did not create two separate playable files, as it did other times. Part 1 is fine, as I said. But just now I checked part 2 on MKVmerge and on MKVextract as an independent file and it does seem to have errors on the headers.

[johns0]

With problem mkvs i split and demux with tsmuxer and remux with mkvmerge.

[carlmart]

With problem mkvs i split and demux with tsmuxer and remux with mkvmerge.

How do I do that?

I don't quite know how to handle TS files. I need it to be MKV. How do I proceed to remux it after splitting?

[johns0]

When you demux with tsmuxergui they aren't ts files,they are .264 and ac3/dts,they will mux back with mkvmerge,only thing you have to do is specify if the file is 23.976 or leave as 25fps with mkvmerge when you load the files,just choose format specfications tab and highlight the video and choose fps 24001/1001 if your video is 23.976.


When you demux with tsmuxer also split the file at the same time.

[carlmart]

Thanks. It did work out.