AVI files displaying with wrong aspect ratio

[The111]

I have a bunch of AVI files from an old DV camera, they are 720x480 NTSC DV Widescreen, 16:9 (not square pixels).

Right now when I view with with WMP or VLC they display as if they are 4:3, i.e. the pixels are square. If I view them in Vegas they display properly, and if I view them in WMP or VLC on my secondary PC (same O/S, etc) they display right.

They also used to display right. I have installed a bunch of different GUI's for x264 lately, have been experimenting with things. Is it possible somehow my codecs are screwed up? What's the best way to wipe them all out and start over? Usually from a fresh O/S install I just add K-lite mega codec pack and that's it. But I guess all these encoders I've been messing around with have added some more codecs, and maybe some conflicts...

[minidv2dvd]

not all players "see" the widescreen flag in the file. the one that do here are wmp11, and quicktime player 7.5.5. the ones that don't powerdvd 8, vlc 0.9.7 and mpc 6.4.9.1( but if you pause, then it does switch to widescreen).

[The111]

Well using WMP11 on my desktop it used to be widescreen, and now it's not. And using WMP11 on my laptop, it is widescreen. So I still think somehow my desktop drivers/codecs are screwed...

Even more to support that theory:
I encoded a 16:9 mp4 from the 16:9 avi, using MeGUI. The mp4 displays as 4:3 on BOTH PC's (while the avi source only displays wrong on the first). So it seems the first PC which is seeing the 16:9 source wrong is actually encoding a true 4:3 output based on its "misinterpretation"?

[poisondeathray]

I can explain the h.264 and .mp4

It's always assumed to be 1:1 pixel aspect ratio unless otherwise specified. Your choice is either encode & resize to 1:1, or use aspect ratio signalling in either a) the container (e.g. .mp4 or .mkv), or b) encoded into the stream using --sar x:y for the dimensions of the pixels

e.g. for a NTSC 720w 480h 16:9 anamorphic encode:

Display Aspect Ratio = Frame Aspect Ratio x Sample Aspect Ratio (same thing as --sar , or pixel aspect ratio)

16/9 = 720/480 x 32/27

so you would enter --sar 32:27 in the command line, which is the non-square pixel w/h dimension

The other container method is easy. You just set it to display as whatever you want. For .mp4 you would use YAMB as the mp4box gui, and enter the sar (its called the par in this case, but means the same thing)

It's always safest to do encode & resize 1:1 , because not all players will support container anamorphic signalling or stream level signalling

For the dv footage, it probably also depends on your choice of splitter and decoder. You can figure out what you are using for directshow players (e.g. mpc, wmp11 but NOT vlc, kmplayer) by rendering a file in graphstudio

And if they display square, that is wrong to0: it would be reading a 4:3 flag. It should be 1.5 if no aspect ratio information was conveyed for a 720x480 frame size

[poisondeathray]

EDIT: double post

[minidv2dvd]

when you encoded to square pixel mp4 did you change the size to a 16/9 output? 720x480 dv needs to be 864x480 mp4 or similar. which what poisondr was getting at.

[minidv2dvd]

you can check which codecs are being used to decode and play the dvavi with gspot. down at the bottom use the 1 under ms a/v and then hover your mouse over the "splitter, decoder, and renderer" if you are using the m.s. defaults it will be quartz.dll, qdv.dll, and quartz.dll

[The111]

Yeh, I see what you guys are saying about the mp4, I'll make sure to re-size it to 864x480 next time. Still not sure why the AVI won't display properly in WMP11 though, when it used to just a few days ago, and will on any other PC.

[The111]

you can check which codecs are being used to decode and play the dvavi with gspot. down at the bottom use the 1 under ms a/v and then hover your mouse over the "splitter, decoder, and renderer" if you are using the m.s. defaults it will be quartz.dll, qdv.dll, and quartz.dll

Awesome, will try that out tonight, thanks!

[poisondeathray]

The flipside, is that when you encode anamorphic or use container signalling for anamorphic display, you save space/bitrate, because it is still a 720x480 frame size, but gets "stretched" to 852x480 on playback (.e.g similar to a 16:9 dvd behaves). Personally, I stick to 1:1 square pixels and resize to whatever dimension makes the appropriate aspect ratio.

Most software players will allow you to display different aspect ratios in the options, so you can override things anyways. e.g. for your dv footage you could simply tell the player to display as 16:9, and not even fiddle with codecs, splitters, etc..

[jagabo]

And digital scaling always leads to artifacts. Since your final playback is probably going to scale the video once again (full screen playback for example) you minimize the number of times the video is scaled if you encode it at it's original frame size.