OGM + AC3: quick guide for no choppy playback and easy cutting.

[BeNooL]

I tried to mux a video and ac3 track into an ogm container with VDubMob. Everything went well I had my two parts with chapters, subtitles and all. Problem is: video is choppy at times and I had audio skips/cracks...

So I searched the forum for a solution and found no direct solution for how to make this. After some experimenting here's a method that seems to work great at least for me.

If it has already been explained, well excuse my ranting then...

I'll assume you have your video (.avi) and audio (.ac3) ready, plus eventual subtitles (.srt) or chapters (.txt)

1st Step
Get Nic's OggMux from the OGG FAQ sticky.
Use it to mux all your files together. You now have a big .ogm that doesn't suffer from choppiness etc only problem is it's *ONE* big file...

2nd Step
Launch VDubMod and load your big ogm.
Use the slider to find the keyframes where you wanna split your video.
Note down the numbers for next step. Also get total number of frames.
Tip: use 'Go to last keyframe' from Edit menu for searching the spot that fits on your media

3rd Step
Get OGM Cutter 1.0a4 here (http://cyrius.bunkus.org/index.html).
This a console mode program. Extract it somewhere in your path and launch a shell (Start -> Run -> cmd).
Goto the directory where your big ogm is.
Now we'll cut it at the exact keyframes we noted down before.
Let's say you wanna cut at keyframe 62558 and total frame number is 146703, then type:
ogmcutter mybigfile.ogm -f "0 62558 62558 146703"
Let it do it's work, and that's it!
Warning: ogmcutter puts all files in the same directory. Check your free space.


You now have 2 parts precisely cut at the exact keyframe you choose.
No stall picture at start of the next part and chapters are also edited so that only the chapters available in the current part are displayed (can be changer with -c option).

[tiki4]

I had developped a similar scheme in former times to do the muxing:

1. I just used Cyrius' Ogmuxer to mux raw AC3 streams into Ogg containers.

2. I used Koepi's OggMux to mux my video with the ogg'ed AC3 streams.

3. I used Ogmcutter like you did.

Nice guide anyway.

tiki4

P.S.: Ah, sorry, that was your first post, so I forgot: Welcome to the forums!

[BeNooL]

Originally posted by tiki4
P.S.: Ah, sorry, that was your first post, so I forgot: Welcome to the forums! [/B]
Thank you!
Actually it feels really strange as I've been reading around here for so long. I'm amazed myself that this is truely my 1st post. Doh!

[Minos]

I want to say that with OggMux 0.9.5.2 by NIC all is very simple:

1-fill all you want in OggMux (xvid in avi, AC3 5.1 , Ogg , Srt ,chapters...)
2-Check the size you want the ogm to be cut
3- all is done (you obtain film-part1.ogm and film-part2.ogm

even chapters are OK (only chapters for the part being played are available !)

No need to use OGMCut

Last but not least , there is no freeze at the begining of the second part (am i lucky?)

Minos :D

[tiki4]

Nic's OggMux modification uses the same command line tools as BeNooL described. Cyrius' Ogmuxer (same author as Ogmcut). It's a very nice tool but I'm not sure if it is stated stable yet. Also it isn't official.

I think Koepi (and others?) are modifying OggMux at the moment to work with Matroska and also with Cyrius' tools. If you get good results with Nic's version you're free to use it.

tiki4

(by the way: I use it, too.)

[Brother John]

by Minos
Check the size you want the ogm to be cut
When splitting by size how do you make sure you don't cut in the middle of a sentence?
Imo looking manually for a suitable keyframe to cut is the only way to asure perfect results.

@BeNooL
You're method works great. The only problem I have: I can't specify a delay for my AC3, the edit box is greyed out. Is this a bug in the GUI or am I doing something wrong?
When using the command line delays for AC3 are perfectly possible. (And Ogmuxer.exe does the splitting, too).

[BeNooL]

AC3 delay is deactivated in Oggmux for the time being it seems.
I had luckly a 0 ms delay so it didn't matter but indeed that's a problem...

When you have no delay correction you can use the GUI.
When you have to correct delay you'll have to get your way through the commande line version.

Surely a new version will come out someday that will let us do this from the GUI.

[zulu]

Anyone of you tried OGMuxerGUI yet? :)

[Brother John]

Yes, zulu. Looks nice but I miss the possibility to cut on specific frames.

I was bored and the AC3-delay-thing annoyed me, so I wrote a little GUI myself.
It's far from being perfect or finished, but it works (no chapters so far).
So if you're interested:
http://people.freenet.de/brotherjohn/visualogmuxer_0104.rar

Any feedback appreciated, of course.

[Minos]

In fact , I have problem to read my .ogm with an AC3 and an ogg audio stream... :-(
It seems that I could see my film with OggDS0995 and zoomplayer, because the audio streams were separated (hard to explain);
in fact,there was 2 "audio menu" in the icon tray of OggDS

Now with version 0996 (I just updated), there is only 1 "audio menu", and I can't switch from AC3 to Ogg no more (the fil mbecomes silent).

I'm trying some of your stuff, and try to mix Ogg and AC3 again (it would be so great!)

[tiki4]

@Minos:

For the time being: Don't!

Different streams in an OGM (e.g. AC3 + Vorbs, or even 2x Vorbis with different quality values) is a no go. This is an issue not entirely solved and AFAIK as long as the stream switcher is part of OggDS filter there is no way to solve the problem. Koepi and Nic were looking into the problem, but I don't know if this issue was adressed at all in the 0996 release by mgerald21. IMHO the name OggDS 0.9.9.6 is a little dangerous as there are no official maintainers of the code and newbies could think this is an improved bugfix release of 0.9.9.5 which is not the case. The new filters are based on 0993 Xiph CVS version and maybe many problems fixed in 0995 by Tobias have to be fixed again.

Cheers,

tiki4

[Minos]

So I think i'm gonna use mkv files instead ! I could add AC3 and OGG audio tracks in such a container !
So i'm gonna say bye bye to ogm :(