Hi

We have a QTKit-based app which a customer has contacted us to report a problem with DNxHD. Basically the alpha channel isn't being output correctly and is full frame white, regardless of the content of the file. I've replicated this myself with the 2.6.0 codec release using any variant of DNxHD.

The app works perfectly with ProRes 4444 or Animation codec files that have alpha, so I'm not sure what is going on here. Any ideas?

thanks

Martin

Are you using DNxHD SDK or QuickTime DNxHD Codec Component?

This is with the QT component.

Martin

Are you setting right Alpha compression parameters in Compression settings window?

This is playback issue not encoding. My test files were made in AE and definitely have alpha channel.

Interestingly the same problem happens when files are imported into FCPX, but they are fine in FCP7.

Martin

digitalheaven2:

the same problem happens when files are imported into FCPX, but they are fine in FCP7.

That is strange. I am sorry, but I could not help you anymore with this issue.

So there are no known issues with this? If not, how do I submit a bug report?

thanks

Martin

** ? **

This is not a known issue. Could you please provide more information in order to create a bug description.

Which resolution is selected in Standard Video Compression Settings? Which alpha? How the movie file was created? What OS(es) are you using? Is it possible to provide 1 frame long movie with the issue?

Oleksii.

Hi Oleksii

I have some more information on this. As I said before this is not a problem with the encoded file, it is the decoding within QT. I've since discovered it only happens in a 32 bit app build and in a 64 bit app the alpha channel is decoded correctly.

It can be replicated by using the CALayerEssentials sample code from Apple, and updating the -(void)setupQTMovieLayer method to use a DNxHD file with alpha. The target architecture will also need to be changed to "32-bit Intel (i386)".

Martin

Any update on this issue please? 

digitalheaven2:

Any update on this issue please? 

Hello, apologize for the inconvenience. Please allow me to escalate this on the right department and provide you an update.

digitalheaven2:

Any update on this issue please? 

I will also ask to get some assistance as soon as possible.

digitalheaven2:

Any update on this issue please? 

Hello, can you please provide a sample file (you can send it on my email) so we can test it from our end.

I've sent sample apps and media file but link will expire in 2 days, so please download ASAP.

thanks

Martin