VSO Software Forum

cedric wrote:Hello cribber,

"Try the test yourself, it doesn't happen on Handbrake."
Do you used CUDA when encoding with handbrake? (I don't think because I can't find hardware encoding option in handbrake...)
So, if you want to do some comparison tests, you need to use same encoder mode in both programs (software H264 encoding).

I will check if I can found something wrong in CUDA high profile, but keep in mind that choosing CUDA encoding will give higher speed BUT lower video quality, you need to choose...
CUDA encoder video bitrate is often limited to 12Mbits/s (depending on graphic card), when software encoding is not limited.
I done same test as your, and handbrake result gives 24Mbits/s video bitrate when CUDA gives 12 Mbits/s, so we can't really compare these 2 files.

Regards,

Now I can't get the Main profile to encode like it did yesterday !! Something weird is going on. The thing i'm trying to explain has (I don't think) nothing to do with Handbrake's 'Software' encoding. The 'High 4.1' profile works fine with 'Constant Quantizer 20' but when you use 'Constant Rate Factor 20' the quality falls apart (both with CUDA). It also works fine with DVDFab CRF 20 (QuickSync & CUDA).

Please download this clip to see what i'm talking about. High 4.1 Profile, Constant Rate Factor 20, CUDA.
http://www.firedrive.com/file/3EE55140741FEEF9

This clip is the same settings but with Constant Quantizer 20, CUDA. (I shortened the length because of my slow upload speed).
http://www.firedrive.com/file/9CD803D0ADFFDADF

Don't stream them as the quality will be poop, download them and you will be able to see the Media Info. Also notice the filesize (CRF 16.8mb, CQ 118mb clipped 234mb originally).

These were encoded from the link I posted on the other page h264_1080p_hp_4.1_40mbps_birds.mkv (original file size 109mb)

Hello cribber,

I worked on your CUDA/Constant Rate Factor issue and I found that CUDA need some additional init when using CRF...
So, you will get better video quality using next beta version (coming soon)

Thank you for uploading your test files.

Regards,

PS: Some converted files from my tests can be found there:
http://oasis.vso-software.fr/Cedric/CUDA_TESTS

I just gave the new version a quick test this morning before work and CRF seems to be working the way it should. I knew there was something wrong and now the bug has been found so thanks for doing this. I'll test a bit more later. I just hope NVENC doesn't cause too many problems when released !

Hi cribber,

Like newly implemented CUDA rate control methods was never used before, I think it's normal that they don't work good on first versions...
I will use same way to init NVENC and NVCUVENC, so you shouldn't have any problems using it. (do you checked if your graphic card will support NVENC?)

Regards,