16:9 DV AVI problem

[vlada]

Hello,

I have an anamorphic 16:9 DV AVI. The problem is, that it only plays correctly in WMP with MS decoder. In MPC with MS decoder the video is 4:3 and choppy. With ffdshow it is 4:3 and smooth in both MPC and WMP. VLC plays it also incorrectly. MediaInfo and GSpot report the video to be 5:4 (720x576). Mplayer crashes when trying to play the movie.

What are your experiences with anamorphic DV AVI?

[halsboss]

What are your experiences with anamorphic DV AVI?

Works fine for me with MPC and ffdshow DV flagged. Also, refer this http://forum.doom9.org/showthread.php?p=1043820#post1043820 for Cedocida for DV decoding...

edit: Hmmm, now I think about it maybe it was "stretched" vertically... will try after work.

edit2: tested; yep you're right... stretched vertically as if 4:3.

edit3: Yep 2Bdecided was right, right-click in the video frame then select "Video Frame" then "Override Aspect Ratio" then select 16:9 and off you go.

[2Bdecided]

On my PC, you need to click inside the MPC window for it to respect the aspect ratio of 16:9 DV. Until you do, it plays it 4:3.

MPC plus a click in the window was the best solution I found. I did manage to force VLC to play it properly, but then I had to reconfigure VLC for other sources. (I bet there's an automatic way of making it work, but I couldn't find it). A newer version of VLC insists on playing it TFF, so that's no good.

(As you can tell, this advice comes from one novice to another!)

Cheers,
David.

[vlada]

I know I can change AR manually. But this is just a workaround, not solution. It should work just like DVDs do. If you have a 16:9 DVD, it will play correctly in almost every player. But 16:9 DV only works correctly in WMP with MS decoder, according to my tests.

I would say it is a clear bug in ffdshow and VLC. I just wanted someone else to confirm the behavior.

[2Bdecided]

It's a common "bug" though - most software checks the MPEG-2 aspect ratio (DAR or PAR), but lots of software ignores the DV aspect ratio flag. I think some software stupidly assumes it can't know the aspect ratio of an AVI, and assumes SD=4:3, despite the fact that the DV stream within the AVI carries aspect ratio information.

You don't need to set it by hand in MPC - there it really is a bug, that it doesn't set the aspect ratio until you click in the window. You don't have to tell it what the aspect ratio is though. Not here at least. Just click.

Cheers,
David.

[colinb]

Is it possible for you to provide a small example AVI file - 2 frames would do. If you send me a Private Message I'd be happy to take a look at the flags.

Can you also try it in DVMP and see how it looks.

http://www.dvmp.co.uk/dv-media-player.htm

[2Bdecided]

DVMP Basic works for me.

Cheers,
David.

[colinb]

DVMP Basic works for me

Good. It sounds like the 5:4 vlada reports from Gspot is the SAR (storage aspect ratio) - the DAR will probably be 16:9.

[JohnnyMalaria]

But 16:9 DV only works correctly in WMP with MS decoder, according to my tests.

Exactly. It's also true of 4:3 though less obvious visually.

WMP10 and 11 work in conjunction with the MS DV decoder to get the AR from the DV itself and not the AVI header. The way to do it is not documented by MS (AFAIK) and third-party decoders can't work with WMP in the same way. Our own decoder is an example.

[cedocida]

@JohnnyMalaria
>The way to do it is not documented by MS (AFAIK) and
>third-party decoders can't work with WMP in the same way

You just have to set the appropriate values in the Mediatype, (VIDEOINFOHEADER2 structure).
I checked this with a ffdshow build and hardwired values and the video was displayed in 16:9 within WMPlayer using the ffdshow codec.
So it seems that ffdshow does not forward the DAR information of the DV encoded video.

[JohnnyMalaria]

You just have to set the appropriate values in the Mediatype, (VIDEOINFOHEADER2 structure).

Cool. I'll give that a try with our decoder - seems simple enough.

John.

[vlada]

Sorry for my very late reply. Here (http://www.sendspace.com/file/7hhvc6) is a sample, if anybody is interested.

Surprisingly with MPEG-4 ASP the AR signaling usually works. But not with DV. So I wouldn't blame just AVI, there certainly is a bug (or missing feature) in most DV decoders.

[SeeMoreDigital]

Hi Vlada,

Your sample is displayed at the correct aspect ratio when played with MediaPlayer Classic's built-in DV decoder...

[vlada]

SeeMoreDigital
I tried it again. I found out it works in VMR but not with Overlay. With ffdshow as a decoder it doesn't work at all. I don't have an internal DV decoder i MPC, but it uses the default MS's decoder. Another issue is, that it starts playing 4:3 (or 5:4) and I have to pause the video, then it suddenly switches to 16:9.

With overlay the video looks like if it was bobbed but without the 1-line shift, so it slightly jumps up and down. With VMR it looks O.K., but it's choppy and MPC eats 50% of my A64 3500+ CPU. I also notice some flickering, similar to the effect I have with overlay mixer, but not that strong. Could it be because of my weak graphics and it's deinterlacer (integrated GF 6150)?

[SeeMoreDigital]

I'm using MPC in VMR9 (Renderless) mode, with a 2.8GHz P4 CPU and nVIDIA GeForce FX5200 graphics card...