dnxhd alpha

[chriss0212]

hi christian...yes...of course my fault

regarding qt animation: problem is the file size...we need to store hundreds of clips on ssd....

greetz

chriss

[Christian Krix Schmidt]

oh boy. that is an issue. I am just right now playing around with the avid codec and the first clip i rendered out from after effects with alpha (750 frames) was 2.5GB. )))) The QT Animation was only 500MB. I definitely have to play around with the settings.

[Christian Krix Schmidt]

OK, i got it. I have the dnxHD codec running under Windows 7 64bit with Ventuz 3.06 with Alpha.
I downloaded the Avid codec pack v2.3.4 at http://avid.custkb.com/avid/app/selfser ... cId=392959

I used After Effects to convert an image sequence to Quicktime with the Avid dnxHD codec. Here are my settings that worked in the Avid DNxHD Configuration window:

Color Levels: RGB Levels
Alpha: Compressed
Resolutions: 1080p/25 DNxHD 36 8-bit

Do not forget to set the Channels to RGB+Alpha in the Video Output settings window of After Effects!!

I will definitely play around with that codec some more. My first 2.5GB file shrunk down to 250MB when I used only Quality of 30. Very nice indeed.

[chriss0212]

hi christian

will test it on the weekend


thx for quick answer and tests

greetz from very cold germany (-15°)

chriss

[chriss0212]

mmmhhhh....

the dnxhd mov definitly is encoded with alpha....and with krix settings...but in ventuz there is no alpha channel

any idear?

greetz

chriss

[Christian Krix Schmidt]

Tsk tsk tsk. My bad. Sorry I just found an alpha node in my scene which made the whole thing work. I will get back to testing the codec setttings. Should have paid more attention.

[ErikB]

Just to quickly comment on the whole codec issue.

It is not as simple as just adding a codec in. We need to implement, verify and test it. But, even that is nothing compared to the legal issues. DNxHD belongs to Avid. It is licenseable, but not entirely without strings attached, especially at a corporate level. When we implemented FFmpeg, we made sure we have proper legal backing for the codecs we implemented and removed all those we didn't want to mess with. We thus did not include DNxHD, even though FFmpeg could do it, simply becaause of the legal overhead it would require. If it works, it is because it is handling it through a different codec (e.g. QT), but I expect it won't.

If it is important, we can consider looking into the licensing agreements and figuring out what that means for us, and depending on that, including it in a future release. The same goes for any other codecs. There are a number of great codecs out there we will not implement because it would require handing over our firstborn, sign away our souls, paying millions of dollars, or other such things...

[chriss0212]

hi eric

dnxhd is working, only alpha channel is missing!

greetz

chriss

[chriss0212]

maybe it is not a problem of dnxhd.....maybe it is a problem of the advanced movie node itself? if i remember correct: it is impossible to use the transparent border option in the mapping properties for the new move nodes!

greetz

chriss

[joysprod]

Hi Guys,

Just realised that Ventuz 4 now supports the playback of Quicktime Pro Res movies. My Christmas has come early!! I have a lot of clients who want to play back with this codec and we have always had to re-encode.

I guess V4 just missed using version 2.1 of MMPEG released on the 28th October? searching Pro Res on their site I found

"- make decoding alpha optional for prores, ffv1 and vp6 by setting
the skip_alpha flag."

Future support in Ventuz 4?

Regards

Peter