crossfade bug?

jasman wrote on 8/8/2005, 4:46 PM

I'm starting a new thread with this info. I'm wondering if anyone else can duplicate this?

I did discover a bug in the standard set of crossfades. You can try it yourself. Crossfade two solid events of the same color with digital values r,g,b from 1 - 255. You should get the same color and values r,g,b during the crossfade, but you'll see that you get r-1, g-1, b-1. For 0 values it works because -1 is not allowed. So during the crossfade the image actually gets slightly darker by one digital code. I can most definitely see this!

An upper track fading to a lower track by pulling back the corner does not exhibit this behavior.

The film style optical dissolve plug-in works great, it does not have this problem. Could this be a reason that the standard dissolve is none too popular?

Comments

MUTTLEY wrote on 8/8/2005, 4:51 PM

Can't say that I ever noticed, crossfades always seem to look fine to me, but than I'm not watching the numbers.

- Ray

www.undergroundplanet.com

Marco. wrote on 8/8/2005, 5:02 PM

I cannot state this, not for the final render. Whilst it is not rendered - o.k., here I have a loss of 1 bit rgb in the preview. But after I rendered it (to dv) everything is fine - not a single bit lost.

Marco

jasman wrote on 8/8/2005, 5:47 PM

I only tested during preview with the video scopes, etc. Interesting that it behaves properly after rendering. I'll test this myself later. Can anyone else confirm either observation?

TheHappyFriar wrote on 8/8/2005, 7:33 PM

I can confirm it. In fact, nobody responded to my thread:
http://www.sonymediasoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=404956

after you render it's still dark (that's how I found it). you don't need to use solid colors, it does it for anything.

however, I found out I had the "ignore 3rd party codec's" UNchecked. I checked it & there were no problems after that.

jasman wrote on 8/8/2005, 9:21 PM

I have "ignore third party DV codecs" checked, and "use Microsoft DV codec" unchecked, and it renders wrong, both to AVI and mpg. The render is just like the preview, all r,g,b values are down one bit from where they should be. With V6,V5, and V4.

TheHappyFriar wrote on 8/8/2005, 9:40 PM

what's the fade type you're doing?

I did this with the default fade (fadetype: linear in linear out) & got no problems.

if you're using a crossfade that doesn't always fade in an equal ammount it's fading out (ie linear in fast log out) then this will happen, but that's not a bug that's by design.

jasman wrote on 8/9/2005, 8:50 AM

Good point about the crossfade type. I was using one of the symmetrical s curve types. I think it should behave properly with any symmetrical pair, since by definition the two scalars are (1-x) and x and that should add up to 1.

I'll try some others when I get a chance.

Sony, what say you?