Compressed or uncompressed

pfac wrote on 9/10/2003, 4:25 AM

Greetings,

I've been producing my second short feature and have been confronted with the following situation: comparing the stuff i've made in Vegas 4, which i've compressed with the PAL DV sonic foundry codec, with the same images rendered also in Vegas but uncompressed, i've denoted a substancial improvement on image quality.
Not knowing if i'm going to pass my DV productions to film, and realising that picture quality is a must, i've decided to render all my projects here on uncompressed.

Now the problem: when i render my sequences uncompressed, the video footage comes with skips and jumps. Why is this?
I'm runing my stuff on a Pentium 4 2.400 Mhz, 512 Mb RAM, 80 Gb hardrive.

Can anyone help, cause the quality of the footage is really preserved if rendered uncompressed.

Thanks!

Comments

RBartlett wrote on 9/10/2003, 5:06 AM

Best with uncompressed, and particularly with IDE drives to have a system HD, an acquisition HD and a target HD. IDE (except WD Raptor) is poor at random access.
DV gets away with it as it is so much smaller. The stuttered rendering is probably an I/O deficiency. I'd invest in storage, not a new CPU or more RAM just for now.

If uncompressed footage plays back well once rendered - you probably have your 80GB drive set OK (mode=UDMA33/66/100/133, 80wire cable etc).

Rendering (in the preview window) usually has the fits and starts attitude. You don't mean that media player can't play the uncompressed do you? If you do, check you have the Intel chipset drivers (possibly application accelerator too) installed.

For quality, you might try an MJPEG format - such as PICvideo, constant quality metric = 20. www.jpg.com. You could try the DigiSuite standalone codecs from Matrox, even with lossless MJPEG compression. Caveat emptor with the Matrox codecs, some report that it upsets other non-MJPEG aspects of your PC. I've been OK though and use both Pegasus and Matrox MJPEG.

MJPEG has the advantage of working in 4:2:2 colour space, where PAL DV is 4:2:0.
If you stay uncompressed, I'd seriously consider a couple of extra 80GB drives and any necessary controller to connect these 3 and the CD/DVD devices to. Always connect the HD as primary/master with nothing else on that same ribbon/cable.

The quality of uncompressed depends really on the source being uncompressed. At least some of it should be to justify operating in this domain. However, whenever you reprocess DV you add to the compression noise. If you don't notice it, you don't worry about it.

Vegas deals with DV and uncompressed natively in its processing pipeline. Other codecs rely on the microsoft subsystem so don't quite get the same good deal.