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Alpha Proxies and normal VP9

Posted: Wed Oct 09, 2019 11:15 am
by cyeary
I have been playing around with the different tasks of making the preview files.  The addition of having alpha is very much appreciated.  However now I have to choose.  Is there a way to have VP9 the default and then just any content that I have that is alpha i make into pro res 4444?  I am assuming I would have to do that manually? Feature request would be to have that auto sense.  So if it sees a file that has alpha it just does it for me. 

Re: Alpha Proxies and normal VP9

Posted: Thu Oct 10, 2019 11:50 am
by Michael Eckschlager
As you assumed, currently you have to choose between those "Preview Presets" so there is no way to create your own presets.
But can you let me know the background why you want to convert your alpha videos especially to ProRes ? 
Because VP9 is also capable of handling alpha. So if you have a video with alpha channel in the ressources and you set the preview preset to VP9 then you will also get a preview video with Alpha automatically.
 

Re: Alpha Proxies and normal VP9

Posted: Fri Oct 11, 2019 7:12 pm
by cyeary
SO I am not getting the alphas with VP9.  I am using the VP9.mov version. The Thumbnail should show alpha as well. This makes programming with a client over your shoulder in pre viz very worried. 

Re: Alpha Proxies and normal VP9

Posted: Mon Oct 14, 2019 12:27 pm
by Michael Eckschlager
Well, you were right about the VP9 and Alpha.
In my test where Alpha worked, the conversion from the preview files to VP9 were not finished completely and that was the reason why I saw the Alpha (from the original file).
After some research it's still difficult to say if Alpha is supported in VP9 or not. There are some example commands available for ffmpeg but they are still not working.
So for now you have to go with ProRes if you want Alpha in the preview.
I will talk to the developers if we can add an example like VP9/ProRes with Alpha
 

Re: Alpha Proxies and normal VP9

Posted: Mon Oct 14, 2019 12:45 pm
by cyeary
While we are on the topic of Proxies. 

Can you explain the difference between VP9/mp4 and VP9/WebM

And is there any reasons we would want Mpeg2/MXF? Isnt that all CPU based?

Re: Alpha Proxies and normal VP9

Posted: Wed Oct 16, 2019 12:28 pm
by Michael Eckschlager
Well, the reason why you can choose between several options in the preview transcoding is relatively simple.
Maybe you have noticed that these options are only available in the beta version (the release just has one default preview).
The reason is that we are trying to get some practical results (pro/conts) for each option.
Because then we are able to recommend some options to specific cases in the future.

So maybe in some cases also the Mpeg2/MXF option has some pro's.
If you have some experiences already, then please let us know.

Re: Alpha Proxies and normal VP9

Posted: Wed Oct 16, 2019 12:40 pm
by cyeary
Understood.  I have just been using the VP9 MOV . I will play around and test more. 

Thanks Michael