Check CCE-encoded files for correct field order ?

[Fudoh]

Hi fellows,

we've received about 1500 MPEG2-encoded files of which some have probably been encoded with the wrong field order choosen in CCE.

Problem is that the files play fine in all software DVD players and media players I know, but give jerky playback when a real DVD is authored with them and the DVD is played on a real standalone DVD player.

So, I wonder, what's the ultimate way to check if they're encoded correctly WITHOUT burning them to a DVD ?

Virtual Dub, Avisynth, CCE - everything's available....

Any hints would be highly appreciated.

Fudoh

[Skelsgard]

U can use ReStream to check GOP properties.

[unskinnyboy]

Using Avisynth..

MPEG2Source("your.cce.encoded.file.d2v")
SeparateFields()

Open the avs in VirtualDubMoD. If it plays jerky, the material is TFF. If it doesn't, the material is BFF.

1500 sounds like a lot of number to go through manually. This (http://forum.doom9.org/showthread.php?t=104760) thread contains an automatic interlace detection tool which you may find useful.

[Fudoh]

Thanks so far !

@unskinnyboy

This is basically the same as the script I use to check the field order in .avi files before encoding

AviSource("...")
AssumeTFF()
SeparateFields()

The problem I see here: I'm quite sure that there are MPEG2 files whose AVI sources have been TFF (analog captures) and some which have been BFF (DV streams).

The question is simply if the line offset in CCE had been choosen properly (in other words, if the MPEG2 stream has been flagged properly).

So I'm not sure what to do with the AVISynth check. What can I tell about the MPEG2 encoding when I find the stream to be TFF or BFF ? Can I conclude whether the file has been encoded correctly or not ??

Thanks,
Fudoh

[unskinnyboy]

Then it's a problem. The only way SeperateFields() would become useful here is if you can know what the field-order of the source was. If you don't, then just by finding out the field-order of the encode isn't going to help you.

Maybe you could try and cut small portions from all of the videos, burn them all onto a DVD, and then try playing that? Then you could note down the ones which play back jerky? That way you don't waste a lot of media. Just a thought.

Even ReStream, I can't imagine even how that can help. The GOP properties would show the field-order, but again we have the same issue - like how can that tell us whether the encode was done with the correct field-order or not?

You said all media players play everything fine. Are they being deinterlaced on play back? If you have already found any video to be wrongly encoded (by burning on a DVD-R and playing on a TV), can you provide a ~10 MB sample of it?

[Trixter]

My quick trick is to play them in VLC with Video->Deinterlacer->Linear set. Linear isn't actually a deinterlacer but is rather a smooth bobber. If the field order is wrong, I find it in a hurry :-) I've double-checked this by burning to a DVD and checking on a set-top connected to a tube television, so I know my workflow is solid.

PS: It helps if you can set your monitor refresh rate to the video standard you're previewing. For example, depending on the system I'm on, I set the monitor refresh rate to 50Hz (PAL), 100HZ (double PAL), or 75HZ if I can't do either.

[kolak]

You can use Nvidia PureVideo encoder (with MP Classic) with hardware acceleration and video mode turn on. If field order is wrong than video will be jerky (like it would be on TV from hardware player).