Encoding speed is "slow"?

[ghost]

First of all, thank you for developing this fantastic piece of software. I'm trying to set up GPU accelerated rendering on my PC. I am using VirtualDub (64 Bit, but tested with 32 Bit as well) to render (fast recompress mode) a 1080p video using the "Balanced" preset, High Profile at 25Mbps VBR. The encoding runs at about 21-23 FPS. I then tested the "Speed" preset, with all three profiles, which didn't seem to increase the render FPS noticeably, maybe by 1-3 FPS, but this is nowhere near what you said it should be able to achieve on the main page. I tested with Sony Vegas too, same results. Then, I downloaded MSI Afterburner. It benchmarked VCE with my GPU at 53 FPS avg. for Balanced, so I wonder why VirtualDub / Vegas can't get anywhere near that? Is VFW hitting performance that much? Any ideas?

Thank you,

• Phil.

[jackun]

Yeah, quality and speed should have pretty big difference. I'll have to re-benchmark. Last time i think i benched with Catalyst 13.12.

[ghost]

Thanks for your quick reply. I am using Catalyst 14.4 if that info is of any help.

• Phil.

[jackun]

Something is funky, x264vfw decodes ~60fps, OVE encodes at ~70fps, yet put together it hovers between 20-30fps. Perf analyzer says only ~15% of CPU time is spent in compress function.

[ghost]

I can pretty much confirm this observation. While encoding video, CPU and GPU usage are always very low, yet it only does 21-23 FPS for me. However, when using Dxtory with OpenEncodeVFW (so no decoding is involved), it easily manages to record a game (way more CPU and GPU usage) with the video at a stable 30 FPS.

• Phil.

[jackun]

Ok, Avs2avi, starts with 44fps and ends with 55fps average. Finishes 4:01 30fps clip in 2:14. Encoder log says it ran ~71 fps.

[ghost]

I have now uninstalled x264vfw and installed ffdshow VFW instead. Now everything seems fine. VirtualDub runs the "fast recompress" with the Balanced preset at 46 FPS average.

• Phil.

[jackun]

To benchmark decoder only, a null encoder Avs2avi + AVS script could be even faster maybe, but ffdshow gives weird frame size of 664x56, eh.

[ghost]

ffdshow decoded at ~130 FPS in VirtualDub with the null encoder you provided. The frame size was normal, 1920x1080, no quirks there.

• Phil.