VirtualDubMod - Matroska output gets boosted height!

[Gew]

Alright..

Let's say I have this 640x480 (4:3) clip loaded and ready for output. When I choose MKV output the "outer box resolution" is somehow changed. I mean, loading my result.mkv in MPC, under SHIFT+F10 (file details) I see the clip itself has the right proportions (640x480). However, the video size is suddenly ..hold on.. let me check.. 640x524!

This of course causes letterboxing by black shades on each side. It has to be something about the MKV, 'cuz I've also tried output as AVI aswell as Vorbis OGM, works like a charm. Then both clip and video size is 640x480. Somehow, Matroska wants to change it. Another thing that may be of interest for any solution..

Video: Xvid 640x480 (160:131) 25.00fps [Video]

Strange PAR value indeed. However, I've tried putting 4:3 / 12:11 PAR/SAR's into the Xvid encoding, this apparently not changing anything. So, what could be the deal here? Thankful for all answers. I'm just a curious little video noobiie.


Regards~

[jagabo]

Check the Xvid PAR/DAR settings before you encode.

[Gew]

Check the Xvid PAR/DAR settings before you encode.

Like I said: I've tried DAR 4:3, aswell as SAR both 1:1 square and 12:11 PAL, just to see if there would be any difference.

None, none what so ever.

[jagabo]

You want Square Pixel. Also, VirtualDubMod's MKV support is extremely outdated. I wouldn't trust it for anything. Although, I just tried it with square pixel and 16:9 DAR and both played properly in MPCHC (640x480 square pixel played 4:3, 640x480 16:9 DAR played 16:9). I also tried 720x480 with 16:9 NTSC PAR it it played with the proper 16:9 DAR.

[Gew]

Yeah, 1:1 is the deal since this all the way LCD bizniz. However, I think I found a clue. Check this out.. I loaded my messy MKV into latest mmg (mkvtoolnix merger gui) to get some inplented specs on the file. I see that it has actually a written 640x524 setting in there. How did it get there in the first place? Since I specificely entered 1:1 in VDB when I the encoded the original data (whitch for the matter were a .mpg á SVCD style).

[Gew]

Furthermore, I tried simple change the view resolution field into DAR field thus entering 4:3; then rewrote the mkv cabinet. The issue was fixed. 640x480 now both on clip and video shown in MPC file info, and no disorted letterboxing.

Anyways, I'm the kind of guy who can't just move on. I want to know what went wrong, and where.. during the phase.. :Z

[Gew]

@jagabo,

Think I follow now though. It's like you said, VDB simply just suffers from an outdated Matroska support. This is the "manual fail-safe debug" I just ran, hrhr..

1) Went back on loading original SVCD .mpg in VDB. Chopped all unpleasent black borders just to have 100% video and nothing to get confuzed about. Resized into 4:3 (640x480) by Lanczos3 stretching. Done with the data!

2) Setting square pixel SAR in Xvid encoder. First output as test1.AVI; second output as test2.MKV.

3) Loaded test1.avi into MMG and clicked the display tab. No pre-defined values at all. In other words, like it should be.

4) Loaded test2.mkv into MMG and clicked the display tab. This wicked 640x524 is somehow written in the width*height field.

5) MMG output test1.avi as finalwrap1.mkv = SUCCESS!
6) MMG output test2.mkv as finalwrap2.mkv = FAIL! (back to the issue)


Thanks for the assistance. Now I know one or two things more than I did before. Wow, that actually rhymed

[jagabo]

I can't duplicate your problem.

<edit> I wrote that before seeing your latest post. I'll try again to duplicate your problem. Is your SVCD source PAL? Not sure if I have any of those.

[jagabo]

1) Went back on loading original SVCD .mpg...
2) Setting square pixel SAR in Xvid encoder....
5) MMG output test1.avi as finalwrap1.mkv = SUCCESS!
6) MMG output test2.mkv as finalwrap2.mkv = FAIL! (back to the issue)

I was able to duplicate the problem! I used an NTSC SVCD MPG file and got 640x640 playback from the MKV, 640x480 from the AVI. It seems VirtualDubMod remembers the source frame dimension aspect ratio from the MPG source and incorrectly specifies DAR in the MKV. I also tried a 720x480 DVD VOB and it gave the wrong playback DAR in the MKV.

[Gew]

Could it be that we have just found an whole new bug? I've always wanted to be the first one to counter a software issue.

[Gew]

Of course, if that is the case you will have ½ the credit, cuz if it hadn't been for you, taking valuable time trying to "duplicate the problem", I would probably just have ended up believing that the problem was rooted in my own cloumsiness, since I'm really no pro when it comes to video stuffs.

[jagabo]

I also just tried a square pixel Xvid AVI file that started as 720x400. I cropped it down to 528x400 (about 4:3) and encoded as square pixel Xvid in MKV. VirtualDub continued to set the display size to 720x400 in the MKV header.

I don't know if this is a new bug or one that was known before. But I don't think VirtualDubMod is under active development so I doubt there will be any fix. I'm using 1.5.10.2. I believe there is a newer build around somewhere.

[Gew]

Aaw.

Yeah, obivously something goes wrong when VDB is writing the Matroska header. I'm also using the 1.5.10.2 build. I've looked for later releases, without any luck. However, true that, by the fact that development seems to have stranded back in y2k6, an update anytime soon would presumably be too much to hope for. Anyways, if (which I doubt, thinking closer on how easy-encountered this 'bug' really is) this flaw hasn't been discovered, it should be highlighted. I just posted a bug report on the Sourceforge project site. I can only hope for someone to eventually read it

[jagabo]

I don't think anybody uses VirtualDubMod to make MKV files.