MeGUI / MKVMerge Speeding up video during muxing.

[Kaiel]

Hello,

This is my first post and though, it doesnt 100% deal with mpeg4, it does deal with MeGUI so I hope I am putting this post in the right place.

I am trying to losslessly back up a DVD. I used MeGUI to strip the video and audio using the file indexer (d2v) tool. Then when I try to use MeGUI to mux the m2v file and the ac3 file together, the muxer speeds up the video.

Both the demuxed video and audio are 1:45:XX long but after muxing, the video ends at ~1:20:XX and the audio keeps going.

I tried muxing them separately in MKVmerge and the result was the same.

Does anyone have any ideas on how to fix this? I did search quite a bit, but didn't have much luck as most people encode the video before muxing.

[nurbs]

Wouldn't it be easier to just mux the .vob directly with MKVMergeGUI? Since you don't do any conversions there isn't really a reason to demux audio and video at all.

[Inspector.Gadget]

Yes, nurbs is correct. Also you may want to check the audio delay of the relevant stream using DGIndex or PGCDemux first to make sure MKVMerge sets it correctly.

[Kaiel]

Nurbs: I will try muxing the VOBs, but the reason I muxed just the video and audio was to get rid of all the extra unwanted streams.

Inspector.Gadget: The audio delay is fine. When I play the mkv file, the audio and subtitles align perfectly, but the 1:40:XX video has been sped up to be only 1:20:XX long, so no amount of delay will help because a 1:40:XX audio track can't match a 1:20:XX video track. I just don't know why mkvmerge is speeding up the video track in the first place. I use mkvmerge on HD content and it has never done this before.

I do thank the two of you for your inputs.

[Inspector.Gadget]

Check the reported framerate in your MKV file. MKVMerge defaults to 25fps when it can't detect the framerate of raw H.264 input; perhaps something similar is occurring with using the demuxed elementary stream as input.

[Kaiel]

Ok guys, I remuxed the video using the VOB files. I played the resulting mkv file in MediaPlayerClassic and it reports the fps to be 59.94. The VOB states fps is 29.9.

How do I stop mkvmerge from doubling the fps?

BTW 59.94 fps doesn't seem right because if the fps were doubled wouldn't the video length be halfed?

[Inspector.Gadget]

MKVMerge isn't doubling the FPS. What's happening is that the NTSC DVD content you have is flagged as interlaced (~60 fields per second) and your MPEG-2 decoder is bobbing it (turning each field into a frame) and so your renderer reports, accurately, that it is being fed ~60p video.

[Kaiel]

Thank you for the information, knowledge is power. Do you know how I can fix this speed issue though? You seem to have a good idea of what is going on.

I found a program MakeMKV that finally did what I needed. But I really want to get this sorted out with MeGUI. I don't like having multiple programs on my computer if I can just keep MeGUI which is multipurpose.

[Inspector.Gadget]

If you're muxing from undamaged VOB (or, as far as I know, even undamaged MPEG-2 ES) with MKVMerge, you should have no trouble. Check under File->Properties->MediaInfo in MPC-HC instead of in your renderer's display the framerate of the newly muxed MKV file from VOB. You should see information that corresponds to 60 fields per second MPEG-2 video, as you would when looking at the original VOB(s) in that view. A shorter video time is consistent with the video's muxing framerate being set to 25fps instead of the correct value, so when remuxing direct from VOB make sure not to explicitly set a framerate in the GUI (or if you do, make sure it's 30000/1001).

[AiDz0r]

Aha, I had the same problem. Thanks.

[7ekno]

I am trying to losslessly back up a DVD.

MakeMKV FTW ;)

Does decryption to MKV all in one for you :P

7ek