MPEGs make my video too dark

[sky captain]

This may be a newbie question, but here goes.

I've been using TMPEG for a year or so, but mostly doing MPEG2 files of animation. Now I'm working in live action, which might have something to do with the problem I'm having.

After editing my piece (using Toaster Edit), I send the project through TMPEG and burn the resulting MPEG to disc. When I play it back, the dark areas of the video have gone REALLY dark, and the chroma is somewhat off. Is there something in TMPEG's settings I can change to fix this?

My bitrate max is 8000, min 2000, and avg 4600. GOP 18. Variable 2 pass.

Maybe I should try rendering through Premiere or Speed Razor instead of TMPEG to see if there's a difference. What a pain.

[lordsmurf]

Your IRE may not be set correctly.

[sky captain]

Is there an IRE setting in TMPEG? I haven't run across that before.

[davefx]

also look into the CCIR601 checkbox. rather than prompt a million page thread, do an experiment with this box checked and then unchecked.

when i use DV i check the box. otherwise i leave it unchecked. it has a pretty dramatic effect at times.

[sky captain]

Are you referring to the "Output YUV data as Basic YCbCr not CCIR601" box in the Quantize Matix tab?

I've got that checked, but I'm still too dark. Actually, it's more of a contrast issue, as my light areas are still light.

How do I change IRE?

[lordsmurf]

How does this look on tv?

[sky captain]

I've been checking everything on an NTSC monitor and a regular NTSC Television.

I'm positive there's a difference because I can switch between my original timeline and a DVD player input on my monitor.

Someone told me today (with a shrug) that MPEG compression is bound to diminish the image, and I should learn to live with it. Detail in black areas is something I can only correct by doing less compression.

So I'm doing a series of tests where my minimum bitrate is raised from 2000 to 3500. After that, I'll raise it to 4000 and raise my average also to 6000 (from 4600).

Also, I'm testing brightness and contrast levels by making picture adjustments and making new MPEGs from those changes.

[edDV]

Sounds like a capture levels problem.
How are you capturing the video?
What is the source?
What is your capture hardware?
What format are capturing? uncompressed?

Are you saying the TV display of the DVD has squashed blacks?

First step rent a DVD with the THX test patterns and calibrate your TV. These patterns are on many Dreamworks, Lucasfilm (Star Wars, Indy Jones, etc.) and many other commercial DVDs. Once the TV is calibrated, you can make quality judgements.

http://www.thx.com/mod/products/dvd/optimizerIntro.html

PS: Also ID your DVD player.

[sky captain]

The video was taken from Beta to DVCAM. Then grabbed digitally through firewire to my hard drive. (Using Video Toaster.)

So there is compression on the digital tape, but the resulting AVI looks great when output to my NTSC monitor.

It's the DVD that looks bad, on the same monitor.

[edDV]

Have we yet established you are in a NTSC environment?

If so the Betacam tape has black at 7.5 IRE. An analog dub to DVCAM will place black at digital level 32 which is incorrect. However if you play the DVCAM to your analog TV it will produce 7.5 IRE black and look normal and identical to playing the Betacam to the same TV.

If you take that tape and digitally transfer it to a DV-AVI file on the hard drive, it will have black at level 32 instead of 16. If you encode this as is without first correcting black level, the DVD will have black at level 32. When you play this back through a NTSC DVD player (NTSC or Component Analog out) the player will assume level 16 is black. It will then add 7.5 IRE setup after D/A giving your DVD video an effective 15 IRE black.

Review this tutorial. Other things may be happening as well.
http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf

Bottom line, your black level needs to be set to digital level 16 before you encode the MPeg2.

[sky captain]

You've given me some good info to think about. I haven't had the chance to go through the whole tutorial yet, but I will.

I'll be back if I have more questions.