Does GPU usage reduce picture quality?

[Kugli123]

Hello Forum.

I just found out about DVDfab and its capability to compress and burn a 50GB Blu-ray to a 25GB disc.

Allthough I have no problems or errors when copying movies, I wonder if GPU (incl. Lightning Shrink etc.) reduces the picture quality.

I often read that you should only use your CPU to re-encode video for maximum picture quality, allthough I didn't really understand why...

Again, I am not talking about ripping Blu-rays to a H.264, x264 standard or anything... I am just talking about compressing and burning untouched blu-rays (main movie only) to a BD-R 25 GB and if I should use CPU encoding only (takes even with my 2013 i7 machine up to 3 hours) or if I can go for all the GPU-tools that DVDfab offers me without any limitations or worries. (30min. compressing).

Hope you can help me out!


Thanks a lot,


Jorg

[SuperFist]

I haven't heard or read about this making a difference in picture quality. Most people, I suspect, use the CPU encoding option because it would be faster than using their not-that-up-to-date GPU. However, if you're experiencing no performance issues using GPU encoding and it cuts that much time out of the process, by all means continue to use it!

[Kugli123]

Hey, thanks for your reply.

Here are some articles & posts about the problem:

http://forum.dvdfab.cn/showthread.php?t=15842 (Copy to BD-R)
http://www.extremetech.com/computing...pu-transcoding (Copy to file)

http://forums.guru3d.com/showthread.php?t=371688

[90312]

I use Intel Quick Sync on everything and if there is a problem I haven't seen it. Compressing a 50GB disc 50% to 25GB there will be loss GPU or not.