CUDA Video Engine Load stays 0%, no hardware acceleration?

[johnny808]

Mediacoder x64 0.8.32.5680
Nvidia GTX 670, Nvidia drivers 340.52
Windows 8.1 64-bit

I've used the H.264 CUDA Encoder to convert MPEG-2 .ts to H.264 .mkv and also H.264 .mkv to H.264 .ts

In both cases, the CUDA Encoder performance is not as high as it could be. GPU Load is at 98%+, but Video Engine Load stays at 0%. I believe Video Engine Load going up is an indication of true graphics hardware acceleration.

I've tried the trial version of 3 different commercial software with CUDA acceleration support. With all 3 commercial software, the CUDA encoding FPS rate is much higher than with MediaCoder and for all 3 commercial software, they all have in common that the Video Engine Load goes over 20%+, not just the GPU Load.

In addition to that with MediaCoder, I get the same CUDA encoding FPS rate whether I enable partial GPU offload or full GPU offload.

It's true that GPU Load is at 98%+, but the fact that Video Engine Load stays at 0%, combine with the fact that CUDA encoding FPS rate is the same with GPU full/partial offload, I may be wrong here, but all this leads me to believe that the graphics card is really only doing CUDA software encoding with MediaCoder, not CUDA hardware accelerated encoding. This CUDA software based encoding also has the disadvantage of giving poorer picture quality if the source is low bitrate.

I had made the same observations about Video Engine Load when I was testing an OpenGL based 3D interlaced renderer on Windows. OpenGL hardware acceleration doesn't really work on Windows. The 3D renderer was working, but it was showing the same symptoms of no hardware acceleration: high GPU Load and 0% Video Engine Load.