A few XviD questions...

[jkuy9]

Hi,

I have been encoding for a few months on and off and just downloaded the new XviD beta3 build. Reading the updated tutorial for usign XviD and Virtual Dub I just had a few questions I was hoping people here could answer.

1. When doing a 2 pass is it best to have the 1st pass set to "fast recomperss" in the Virtual Dub Video menu? I have always just left it on Full Processing in the past. If it is best to do this why? Does it speed up the 1st pass? and should I also do the second pass in Fast Recompress or Full Processing?

2. When wanting to use Ogg Vorbis audio do I have to use an OGM or is it possible to mux Ogg Vorbis into an AVI? I ask because Media Player Classic will not play an AVI with Ogg audio. I assume it is not possible.

3. What exactly does the Turbo ;-) option do in the XviD codec? I cant seem to find any information on it. I assume it speeds things up but does using it degrade overall video quality, etc?

Cheers in advance.

[frodoontop]

1. Use Virtualdubmod instead and always fast recompress, so no color conversion has to take place. It will stay in YV12. I believe virtualdub doesn't support yv12 yet. It should give you some speed boost too.

2. To use vorbis audio in movies, you have two options. Use OGM or Matroska. I prefer the last one though ;) . Avi isn't able to handle this codec yet and maybe never will.

3. Turbo mode should enhance speed and sacrifices quality and size a little. I don't use it, but maybe you like it.

[jkuy9]

Thanks for the reply frodoontop

Regarding VDubMod I have never worked out how to mux audio with it. Is it just for video? I was a little confused with that so I just left it!

I have never heard of Matroska before but I will look into it.

Cheers again.

Also does anyone know where I can download custom Quant Matrix to have a look at them and test them out, etc. I kind of understand what they are for, etc but i am not 100% and would like to have a play. If you have any other advice please post it :D

[mikeX]

since xvid 1 beta 3 koepi was kind enough to supply a collection of the most common custom quant matrices in the installer. they should be in a .zip file in the directory you installed xvid at (also accessible from the 'Start Menu'). extract them somewhere and load whichever you want...

vdubmod isn't that hard to use, there are guides @ doom9
for muxing audio just go to 'Streams --> Stream List' and add your desired audio (or even subtitle) streams ;)
if you wanna mux to matroska i suggest mkvtoolnix though (since vdubmod is a bit outdated at the moment). have a look at 'New A/V formats - Containers' here in the doom9 forum to catch up both on matroska & mkvtoolnix (there is a thread about ogg in avi there as well)
enjoy...

[Koepi]

You can of course also mux the files into OGM with i.e. OggMux, should be more straight forward to use if you have problems with the streamlists of vdubmod.

I'm still looking to the OGM compatible firmware from elta for the mediatek based standalone players - let's see if they keep their promise :)

Regards
Koepi

[jkuy9]

Hi

Thanks to you both for replying. I will give VDubMod a go at home now I know how to use it ;)

I have made a few OGMs before however they cant be played in my KiSS DP-1000 standalone player which is annoying, however I did know about this and if I ever do get an OGM converting it to an AVI ith MP3 audio isnt exactly difficult.

I will have a look for the custom quants. cheers for the tip :)

[celtic_druid]

Regular VirtualDub has supported YV12 in fast recompress since v1.5.6.

[jkuy9]

just had a quick look at the example matrix files. i can guess from the filenames what each is for but does anyone have a bit more info on exactly how they work.

I know that I will get better results with Ultra Low Bitrate Matrix.txt than i will with MPEG.txt if i am using a very low bitrate (well i assume that is right, is it? :confused: ) but I would like to know what makes it better, etc. i am not looking for a full technical overview (unless you want to give that heh :D) just a bit of info on what the differences betwen Intra and Inter Matrix is and what the numbers mean, etc. just like a basic overview. I cant find this anywhere :(

[JimiK]

Well I did a quick search for "quantization matrix" then I found a thread where the same question was asked. It had a link to the following thread: really big explanation of quant matrizes (http://forum.doom9.org/showthread.php?s=&threadid=54147&highlight=matrix)
Happy reading,
JimiK
P.S. very quick, the intra matrix is used for I-Frames (Keyframes). In these frames all macroblocks get encoded. The inter matrix is used for P-Frames and motion vectors are used to reference earlier frames (the inter matrix is also used for B-Frames).

[Didée]

JimiK: a small technical correction:

For P-frames, both inter and intra matrices are used:
If for a given macroblock no good reference can be found, the block gets coded as 'intra'.
B-frames indeed are coded as 'inter' exclusively.

- Didée

[plazz2000]

Originally posted by Koepi
I'm still looking to the OGM compatible firmware from elta for the mediatek based standalone players - let's see if they keep their promise :)

Koepi,

Do you know if the OGM firmware will also support Vorbis audio?

All of my OGM's have Vorbis audio, and I suspect most people who use OGM use Vorbis too.

[Alxemi]

Do you know if the OGM firmware will also support Vorbis audio?

Hell i hope it will because of two reasons:

1.-Vorbis audio in standalones is not a challenge anymore
2.-OGM container without Vorbis audio has no much sense.

I think the question is:
the OGM firmware will support embebed subtitles?

afaik, nowadays there is no standalone player that can play subs, but ascomtec people (mediatek based) has announced a firmware that will (no idea of formats or dates).

[DanielSun]

Originally posted by frodoontop

2. To use vorbis audio in movies, you have two options. Use OGM or Matroska. I prefer the last one though ;) . Avi isn't able to handle this codec yet and maybe never will.


Can that be true,i just did a encode,and mux 2 of vobris audio into an avi file.i did use graphedit.

[Koepi]

DanielSun:

you muxed it in, right.

How's the playback?

Did you try to seek forward in the video?

What happen after even 40 minutes playback without using search? Are audio and video still in sync?

Regards
Koepi

[Prettz]

Originally posted by Didée
JimiK: a small technical correction:

For P-frames, both inter and intra matrices are used:
If for a given macroblock no good reference can be found, the block gets coded as 'intra'.
B-frames indeed are coded as 'inter' exclusively.

- Didée
The inter matrix is used to encode just the predicted residual, correct?