I got a new Nvidia GPU to speed up my video encoding. I am working with x264 files to x265 and wanted to go faster. Using the library libx265 I am getting about 85fps when working on a file that is 720p, but if I use the nvenc_hevc I get around 600-700fps
My input file is 269M and when I use the nvenc_hevc it grows to 394M. Doing the exact same command with libx265 gives me a file size of only 68M. Obviously I would like to keep the low file size, but take advantage of the GPU to process it 15X faster.
Anyone else have any experience with this video codec? My understanding is that the difference between libx265 and nvenc_hvec is not the algorithm that is used to do the compression, but that it utilizes the GPU to accelerate processing. With that understanding the resulting file sizes would be identical regardless of which I used, just the nvenc_hvec would be faster. Is that a faulty assumption?
My command is: ffmpeg -i infile.avi -c:v nvenc_hevc -rc vbr_2pass -rc-lookahead 20 -gpu any out7.mp4
vs
ffmpeg -i infile.avi -c:v libx265 -rc vbr_2pass -rc-lookahead 20 -gpu any out7.mp4
When encoding I seem to only be using a small percentage of the GPU despite the huge performance increase:
nvidia-smi -l
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 21954 C ffmpeg 93MiB |
+-----------------------------------------------------------------------------+
Tue Nov 8 20:41:45 2016
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 367.48 Driver Version: 367.48 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 960 Off | 0000:42:00.0 Off | N/A |
| 1% 63C P2 37W / 160W | 95MiB / 4037MiB | 11% Default |
+-------------------------------+----------------------+----------------------+