VV preview quality

taliesin wrote on 6/12/2002, 3:05 PM
Hi there,

can someone state the VV dv-preview is always made with some quality reduction, if there is NOT an original VV captured or rendered clip in the timeline, even if the best settings are chosen?
I don't mean the final output or the rendering itself - just the real-time preview output through the dv-deck of UNRENDERED files.

For example:
I have a TIF image in the timeline. I can preview this TIF image through the dv-device without the need of rendering it.
But if I render it then it seems to look slightly better.

I'm just about to do a codec quality test but I'm very unsure now if I can rely on the realtime preview output as long as I didn't render before.
So it would be helpful to me, if somebody could state what I assumed or explain what I could do.

TNX Marco

Comments

SonyDennis wrote on 6/12/2002, 4:11 PM
Video Preview render quality will match final render quality only if these two things are true:

1) It is set to "Best" quality (actually, if it matches the project property "Full resolution rendering quality")

2) "Display at Project size" is on.

The on-the-fly DV compression is the same as the pre-render in this case too.

///d@
taliesin wrote on 6/12/2002, 4:33 PM
Oooh, I hoped you would NOT say this. If it is so, then I have just stated that there is a quality loss even after the first rendering!

But I cannot imagine this is so. There must be a difference anywhere between the processes of viewing a real-time preview and a rendered file.

Marco
taliesin wrote on 6/12/2002, 5:03 PM
I'm still analizing what the difference is.
I used an PNG-image to do the test. But the PNG image is 32 bit, DV video 24. I think that's it. It's not a codec fault it is simply the fact dv-video must have 24 bit images.

I have to choose a different kind of image for the test!

Marco
taliesin wrote on 6/12/2002, 5:36 PM
Mmh, I made my picture into a dv-sequence now. Captured it the regular way into VV.
Then I made ten render generations.

It's always the same result (right as with the images I used before):

The unrendered video looks slightly different compared to the rendered one.
But it doesn't matter then whether it is second generation or tenth generation, no difference here!!!
So I still believe there is something different only in the way rendered or unrendered files are displayed.

Marco
taliesin wrote on 6/12/2002, 5:54 PM
No way. Whatever I do - There is a loss after first rendering!

I printed the tenth render generation back to tape and captured it again to see if this ones looks the same like the first capturing without any rendering. No. I can't tell you any other words than "there is a loss after first rendering".

Marco
taliesin wrote on 6/12/2002, 7:49 PM
I found out what was going wrong. Take a look at the new thread "preview o.k. - hsl adjust incorrect"

Render quality of VegasVideo is very fine! It was only the hsl-balance filter which did something strange to my test pattern.

Marco