DXV picture quality ?

[ondrejsevcik]

Good morning,
is the picture quality of DXV codec really not so good or my eyes are so bad already?
I've converted one nice sunrise shot which has really smooth gradient from orange to black in apple prores but the smoothness is gone in DXV.
The same in many other cases. Everythink looks worse in DXV than in prores for example. I know it probably is because of data rate and playback smoothness but ... ?

[edwin]

ProRes is an intermediate codec, which means it is intended for use during video editing. So comparing the two is not really fair. But we do agree on the fact that DXV's picture quality can be improved, and especially gradients suffer from the compression. If you have some footage converted to DXV that doesn't live up to your standards use Photo-Jpeg as a fallback.
Could you send us a short clip of the sunset (uncompressed) so we can have a look and use it in the future as test material? send it to mail [at] resolume [.com]

[the_psychologist]

I would stay far away from DXV. The file sizes are massive, even larger than other HQ codecs. I ended up going with Picvideo MJPEG, and you can buy a personal use license for pretty cheap. What all these codecs do is render every frame as a keyframe, which allows for really smooth playback (forward, reverse, random, speed up/down). Why DXV pumps out such large files is beyond me.

[Basic]

I find that DXV works fine. ive never had a problem and i dont see why people have issues with large files sizes. its part and parcel of being a vjing. ever hear a dj complain "i have to many songs?"

[the_psychologist]

Well, file sizes tend to be much larger for video, yes? And I want to keep all my clips on SSD, so the smaller, the better (as long as quality stays high). Why would you want to have a DXV collection that is way larger than it needs to be?

[edwin]

DXV is a codec that was developed to minimize the CPU load, all decompression is done on the GPU. The file sizes are quite big, although in some cases files encoded with a mjpeg codec are actually bigger. So the tradeoff is CPU load versus size. The DXV codec enables you to run much higher resolution video on less powerful machines, if you're machine can handle the resolution you want to work on encoded in mjpeg en the performance is good enough go for it. But you can't advise someone to stay far away from DXV because the files size are too big.
We can make the files smaller by adding some more compression but this will increase the CPU load, but it is something we are investigating and hopefully we can reduce the file sizes in future versions of the codec.

[the_psychologist]

It all depends on your needs. For my case, space is still a priority because I need to fit the clips on SSD. SSD is expensive, so I tend to buy 60GB volumes (which also seem more stable than larger SSD). I also want to be able to play my clips in VLC and other media players (one never knows what sort of casual VJing one will be doing) and I think DXV doesn't play outside of Resolume? Thanks for the info, though. Good to know that low-spec computers are happier with DXV.

[Joris]

I think DXV doesn't play outside of Resolume?

The file should play, but it is only GPU accelerated when played in Resolume, so it could stutter a bit on slow harddrives.

DXV was designed to achieve the highest and smoothest playback framerate possible, not the smallest file size possible. If you feel that for your workflow and VJ style M-Jpeg is best, of course there's no reason to use anything else. I'd be curious to see an AB comparison of the FPS of your clips in M-Jpeg vs DXV though.

Joris

[edwin]

DXV is a quicktime codec, only when played in Resolume it will be GPU accelerated. When the DXV codec is installed on a system all DXV quicktime files will just play fine. The files play just fine on my machine in Quicktime Player or any other tool that supports Quicktime playback. VLC doesn't seem to like it though, they probably don't support all quicktime codecs but use FFMPEG for playback.