Why pixelated transition with HDV rendered to WMV?

prairiedogpics wrote on 5/29/2008, 11:42 AM

I render to .wmv file from HDV footage (Sony HC7) with project properties set to progressive (for use on Vimeo) and when I play the .wmv file on my PC the transition from a Pro Title clip to footage is severely pixelated during the transition; after the transition the footage looks fine.
I uploaded a sample of this to Vimeo for you to see; after they convert it to flash it looks fine. (?) Please download the wmv version onto on your PC (see link on lower right) and tell me if you see the pixelation:

http://www.vimeo.com/1086580

Thanks,
Dan

Comments

busterkeaton wrote on 5/29/2008, 11:50 AM

Looking at the clip, I don't see the pixelation. What bitrate are you rendering to?

Some transitions do not work well in the online world. The reason is the bitrate. If you are something like a dissolve where every pixel in the frame is affected, the encoder is going to have to struggle to keep up. If the bitrate is too low to capture the changes to all the pixels you will have artifacts like pixelation. I believe a longer dissolve would be be more likely to have artifacts. It also depends on the footage. Footage with more movement would be more likely to have artifacts during a dissolve.

When you edit for online you have to be aware that the you may not be able to use all the transitions you would be able to use for broadcast work.

prairiedogpics wrote on 5/29/2008, 12:03 PM

Buster, did you actually download the wmv version on the lower right and play it on your PC? (the flash version looks fine on my screen too, it's the wmv version that's weird.)

busterkeaton wrote on 5/29/2008, 12:08 PM

Whoa, this is wierd.

The first 2-3 times I played the clip, I didn't see any pixelation.

I went away from that page and did some more surfing and posting in my browswer. Then I went back and played that clip again and the entire clip is super pixelatted.

However, when I tried it again. It worked fine several times in a row. So this probably is due to deliver/browser caching of the file, not the actual render.

Also if you send Vimeo a WMV file, do they convert it to something else? It seems there preference is for an mp4/h.264 file.

busterkeaton wrote on 5/29/2008, 12:10 PM

No, I didn't download the WMV.

You have to be a member of VIMEO to do that.

prairiedogpics wrote on 5/29/2008, 12:25 PM

yeah, they convert it to Flash. You can upload wmv or mp4 (h.264).
Signing up is pretty painless; they just need an email address. I used my "disposable" hotmail account.

I really want someone to download the wmv version.... :)

rs170a wrote on 5/29/2008, 12:37 PM

Dan, I played the download in Windows Media Player, Media Player Classic and VLC.
I didn't see any pixelation anywhere.

Mike

prairiedogpics wrote on 5/29/2008, 12:46 PM

Thanks, Mike.
that's good news. Could the pixelation I see be product of my video chipset or or my LCD screen?