How can I know if Avi is progressive or interlaced ??

[apalace]

Hallo everyone!

I am following a guide right now for converting Avi to DVD , and I stopped now by option in CCE and this option is depending on the my video source if it is interlaced or progressive...

Now how can I know if my source avi file a progressive or a interlaced video ??

Thanks for any help!

[thecoalman]

http://www.digitalfaq.com/capture/interlace.htm

Unless it was deinterlaced or filmed with a DV cam that shoots progressive most likely it's interlaced.

[apalace]

Thanks alot for your quick answer.

The Video is an AVi file with xvid codec, it was 2 files with 700 mb each, I joined the 2 parts to be only one avi (xvid) file.

No it isn't from a cam or VHS , like I said just a movie that is in avi format has been converted from a DVD.

And now how can I know if this avi file is Interlaced or Progressive please ?

Thanks for your help in Advance!

[apalace]

Ok, thanks thecoalman, I found the answer in the link you gave me , it says :

All film source is progressive.

Thanks for your help!

[courtneye]

Hello- Even if I start from an interlaced source and have my capture hardware/software create a 29.97i avi, some software thinks that my avi file is progressive. Why would that happen? Does avi really distinguish between interlaced and progressive?

Also, how does avi handle pixel aspect ratio? Is there a standard way to indicate what the PAR of an avi file should be?

Thanks in advance for any info.

[Cornucopia]

When I hear "Xvid" as a codec, it makes me suspicous that your hardware/software DID NOT keep it interlaced (it IS possible to stay interlaced in Xvid, but most software is NOT set up to deal with it correctly)...

The AVI container has flags that explain if it's interleaved or not (dwFlags:AVIFILEINFO_ISINTERLEAVED), but this can and IS ignored by some/many software. AVI does NOT have explicit flags for AR, but does have both stored dimensions (Width, Height) AND Destination Rectangle (rcFrame:AVISTREAMINFO), so a SMART app could figure out that this means the DAR and use the source dimensions to fill it. But again, most apps ignore this and use whatever AR info resides within the Video codec's header/bitstream...

Scott

[jagabo]

Ok, thanks thecoalman, I found the answer in the link you gave me , it says :

All film source is progressive.

Not when it's broadcast. It is telecined to 59.94 fields per second. You have to inverse telecine back to 23.976 fps if you want it progressive.

The AVI container has flags that explain if it's interleaved or not (dwFlags:AVIFILEINFO_ISINTERLEAVED)

That's interleaved, not interlaced. It refers to the interleaving of audio and video streams. AVI doesn't have an interlaced flag. Individual codecs can include that information in their private data.

Hello- Even if I start from an interlaced source and have my capture hardware/software create a 29.97i avi, some software thinks that my avi file is progressive. Why would that happen?

In all likelihood the software you're using deinterlaced before saving the video. People get upset when they see interlace comb artifacts so many programs/devices will deinterlace automatically.

[Noahtuck]

jagabo, do you realize you just quoted and answered someone that posted in 2005 ?

And not the gimlet who dug up a 7 year old thread...

Yes, i am talking about YOU, courtneye,

[jagabo]

jagabo, do you realize you just quoted and answered someone that posted in 2005 ?

So what. The thread was already revived and contained inaccurate information.

[Noahtuck]

jagabo, do you realize you just quoted and answered someone that posted in 2005 ?

So what. The thread was already revived and contained inaccurate information.

So what ?

Just sayin'....

[courtneye]

Hi all- Yes, I saw a couple of threads from awhile back because I was trying to answer my question without posting about something that had already been resolved. But the other threads weren't totally conclusive.

I'm trying to figure out if avi is the best format to preserve my interlaced video. So basically, I'm trying to create a file copy that is the most similar to the original as possible. Is avi actually capable of preserving an interlaced video as interlaced video?

-Courtney

[jagabo]

Is avi actually capable of preserving an interlaced video as interlaced video?

Yes it is. But it depends on what compression codec you use. And since the AVI spec doesn't have a flag to indicate the video is interlaced you may have to manually tell your editor/encoder/player the video is interlaced.

Note that the ODML extension to AVI has a flag to indicate interlaced video (though, as far as I can tell, no flag to indicate the field order). But I don't know of any program that writes or reads that flag.

[courtneye]

Hi jagabo- Thanks for your quick reply! I'm currently creating ODML extension avis with the uncompressed codec, YUY2. So I don't think my codec will identify whether the video is interlaced or progressive. Also, I don't think you're right that my capture/encoding program isn't writing the flag that might appear in the odml structure. Are you thinking of the following flag?

Number of Fields Per Frame

One or two, depending on whether the video is interlaced or progressive.

Also, the program does seem to be writing information about how to display the file though- it has a PrmA and PARf field where it seems to describe the DAR. Have you ever seen that before?

Thanks-

C

[jagabo]

I'm currently creating ODML extension avis with the uncompressed codec, YUY2... I don't think you're right that my capture/encoding program isn't writing the flag that might appear in the odml structure. Are you thinking of the following flag?

Number of Fields Per Frame

One or two, depending on whether the video is interlaced or progressive.

Yes, that's the flag I was referring to. What program are you using to create the video? To examine the ODML flags?

In any case, whether it's flagged or not, many programs won't pay attention to the flags. So you may need to tell the editor/encoder/player that the video is interlaced.

[courtneye]

I'm using Edius software and Canopus hardware to create the file. Generally, I use HxD Hex Editor or MediaInfo or GSpot. I've just started checking out VirtualDub.

It looks like that flag is in the vprp chunk, but I don't think I've ever seen that chunk in any of the files I've created.

[jagabo]

I don't think I've never seen the VPRP chunk. Only the DMLH chunk. Probably because that's all you need in order to make files over 4 GB.

[courtneye]

Got it. Thanks again! Also, shortly after the DMLH chunk in our file we have a JUNK chunk that I just noticed and that contains some interesting text.

F r a m e r a t e : 2 9 . 9 7 ( 3 0 0 0 0 / 1 0 0 1 )


P i x e l a s p e c t : 0 . 9 0 0 0

That's pretty good info, expecially about the pixel aspect ratio. I doubt it's readable by an sort of application, but at least it's human-readable

[jagabo]

Got it. Thanks again! Also, shortly after the DMLH chunk in our file we have a JUNK chunk that I just noticed and that contains some interesting text.

F r a m e r a t e : 2 9 . 9 7 ( 3 0 0 0 0 / 1 0 0 1 )


P i x e l a s p e c t : 0 . 9 0 0 0

That's pretty good info, expecially about the pixel aspect ratio. I doubt it's readable by an sort of application, but at least it's human-readable

Yes, a lot of programs put some information in the junk chunk. VirtualDub writes the VirtualDub version number there. But it's main purpose is to align the later chunks on a sector or cluster (ie, 515, 1K 2K, 4K, etc. byte) boundary. You can't count on the JUNK chunk(s) to contain anything useful.