MS DV multiple encodes = darker?

[fluggo99]

Now, I don't do DV editing (like to someday), but a fellow posted a very interesting problem on a Microsoft newsgroup recently.

He says that using the MS DV codec, successive recompressions eventually made the picture look darker. This happened whether he did it back and forth on files or if he contructed a filter graph to accomplish the same thing. I was wondering if anyone here had noticed this phenomenemenon?

[wkulecz]

Yes, checkout:
http://members.home.net/dgcom/MiniDV/DVcompressors.htm

Color shifts towards darker and more saturation. Very painful after five generations. Major limitation for serious work in MS Pro6.0 with cheap firewire cards like the Pyro as they were expecting the MS DVcodec to work. There are other audio sync and noise problems (see eariler threads by jeff b) that make the Marvel less pain at present unless you've $500 to spring for a Canopus DV Raptor.

--wally.

[dgcom]

Yeah, and what news group it was exactly?

Thanks,
DGCom

[DrMordrid]

Interesting.

I tried multiple generations with the RT-2000 DV codec in MSPro6 and all I got was the expected generational artifacting. No darkening and if there was a color shift it's very slight.

Basically the artifacting consisted of a few groups of colored pixels, block and mosquito DCT artifacts, naturally worsening between 5 & 10 generations, but nothing else.

I didn't see anything like the vertical banding shown in your MS codec pix.

Hmmmm....

Gimme a day or two and I'll up 'em to a web page.

Dr. Mordrid



[This message has been edited by DrMordrid (edited 27 April 2000).]

[fluggo99]

The guy got a reply, and I quote:

"The darkening effekt had been a problem for users of PAL cameras and MS dvcodec
up to late summer 1999. Later versions of the codec didn't cause a darkening
anymore. There was discussion about it on rec.video.desktop. Aktual version of
the codec (qdv.dll) is 6.01.05.0321. You may get it from ADS www.adstech.com
out of the PYRO drivers section. The file called dvconnect.exe installs all
updated dv and 1394 relevant files from MS and the TI cameradriver, which you
have to remove if you want to use msdv driver.
I wonder why WIN2000 release doesn't have the aktual codec."

So there's the story. And go figure, I have absolutely nothing to contibute to this thread

[dgcom]

Stop!

Windows 2000 codec IS the same as 6.01.05.0321 for Win98.

Also, there where a lot of problems with previous codecs, the above mentioned compression artifacts exist with either 6.01.05.0321 or Windows 2000 codec.

Microsoft is aware of it, but nobody knows when they are going to fix it. And codec in Windows ME got those problems too. Even more - if they don't fix something else, Ulead MSPro 6 will be unusable for DV/OHCI editing in it...

DGCom