Flickering on processed DVB captures

[Theaetetus]

I have been backing up DVDs for two years now and have learnt everything I know from Doom9: scouring the Guides and the Forums for the fragments of information that go towards solving all the problems I’ve encountered. However, having turned to recording Terrestrial Digital TV broadcasts in Britain, I cannot solve the problem of flickering when I process some, but not all, broadcasts. So this is my first ever posting.

My way of working is as follows:

• Record the broadcast with a Panasonic DMR-E50 on to DVD-RAM disk.
• Demux the MPEG2 and AC3 streams from the VR_MOVIE.VRO file on the RAM disk to my hard drive, using VobEdit v0.6.
• Edit out the advertisements etc. with VirtualdubMod.
• Frameserve the edited version to CCE. (‘Video’ settings: Add Sequence End Code; Upper Field First; Linear Quantizer Scale; Zig-Zag Scanning Order.)
• Author the resulting .mpv and .ac3 files in DVDMaestro.
• Make an image file of the output with IfoEdit.
• Burn the image to DVD-R disk with DVDDecrypter.

Even though I use this same process with every broadcast, the results are different. Some are of perfect quality, yet others have a horrible flicker as soon as there is any movement of the camera or the figures. Interestingly, if I just author the raw, unedited streams in Maestro, there is no flicker in the end product.

My intuition is that it has something to do with the Interlacing: perhaps some films are progressive and then they are broadcast as interlaced, whereas others are interlaced already and are then subjected to further interlacing when broadcast. I don’t know, I am at the limits of my knowledge as you can probably tell.

I would be very grateful for any sliver of light that could be supplied.

[bb]

Although I have no clue why you reencode your digital streams, your problem with what you describe as "flickering" is the wrong field order chosen during encoding.

If I were you I wouldn't reencode, but clean the stream with Project X (x08), cut with MPEG2Schnitt (German, don't know if there's an English version), and author with my favourite authoring software. I believe there's some free VRO support software available, too.

bb

[Kika]

First: I agree to bb, why are you reencoding your Videos?

(‘Video’ settings: Add Sequence End Code; Upper Field First; Linear Quantizer Scale; Zig-Zag Scanning Order.)

This settings are completly wrong:
Your Source ist interlaced from Broadcast, and CCE is one of those stupid Encoders with idiotic meanings to the Field Order. Don't select Upper Field First.

Linear Quantizer Scale is the old methode from MPEG1, use Non Linear.

Zig-Zag Scanning Order is made for progressive Video, in your special case, you have to use Alternate.

[Theaetetus]

Firstly, thanks to both Kika and bb for replying. I am reencoding the video because I have been following the Guide 'VirtualDub Frameserving'. Admittedly, I have no detailed knowledge of its full capabilities, but it states clearly that you have to frameserve to an encoder to produce a MPEG2 stream as VirtualdubMod outputs .avi files only. Perhaps there is some other way of achieving this output having used its editing capabilities, but of which I am ignorant?

Thank you for giving me the alternative settings for CCE; I have been following the settings given in the 'Full DVD Backup guide'. I'll give them a go and let you know how it turns out.

As for the Project X and MPEG2Schnitt, I will try them out if all else fails, but I am trying to use the tools with which I am most familiar at the moment.

Thanks again

[Theaetetus]

Kika. Just completed processing a broadcast with your CCE settings and the result is, no flicker. I'm ecstatic; this problem has been bugging me for couple of months now. Many, many thanks.

[bb]

Originally posted by Theaetetus
I'm ecstatic; this problem has been bugging me for couple of months now. Many, many thanks.
You'll be more ecstatic when you discover that you don't need to recompress, which is much faster (because there's no MPEG-2 encoding) and you don't compromise quality.

Give the above mentioned tools a try ;)

bb

[Kika]

I have been following the settings given in the 'Full DVD Backup guide'.

Yeah, i have seen this "Guide" now. It includes a couple of faults. :devil:

Never use Upper Field First. CCE isn't able to do a correct BFF (that's the same than UFF in CCE) Encoding.
If this setting is used on progressive Source, the Video is shifted 1 line up. This effect is known since Years!

Never use "Auto" on Intra DC precision. It is still buggy. Better use 9 or 10 Bit.

Never set Min Bitrate to 0. CCE is acting a little dump. If you say 0, he might use to low Bitrates is some Parts of the Movie. And some Players will have problems like stuttering if heavy variations of the Bitrate in the Movie appear.

[Theaetetus]

bb, I've been thinking things over and I will try the two tools that you recommend. It will indeed be worth it if it cuts down the time. I just hope that I can find my way through the German version (I'm ashamed to say that I have not one particle of knowledge about the German language.) I would have used it in the first instance (I was looking for a way of editing mpeg2 streams with as little messing about as possible) had it been mentioned anywhere else on this site. It ought to be if it's easier than VirtualDub.

Kika, thanks for information about flaws in the guides I've been using. I have been following them blindly, without having the background knowledge to know that they might be wrong. Someone should be told.

[Theaetetus]

Managed to get Mpeg2schnitt working (I'll need to get a German/English dictionary for the finer points.) It's the dog's bollocks (quaint old English expression indicating strong approval.)
Thanks.

[bb]

I translated the program. It will soon be available at Doom9's downloads, but you can send me an e-mail, if you can't wait ;)

bb