DaVinci Resolve (Studio) video editing applications are highly optimized for hardware acceleration by GeForce RTX graphics cards. These can dramatically reduce the time of some tasks, turning hours into minutes or, for larger projects, days into hours. We’ll take a look at what exactly this is about in a two-part miniseries dedicated to streamlining work in Black Magic Studio video editors with NVIDIA Ada Lovelace GPUs.
AV1 and HEVC encoding
The new GeForce RTX 4000 cards introduce the capability to performa hardware video compression to AV1 format, whereas previous generations of cards only support HEVC format. This is significant as the NVENC encoder is expected to perform better when using AV1 compression compared to using HEVC compression.
Higher compression quality in this sense means that you achieve a certain level of visual quality at a lower bitrate than you would need when outputting in HEVC format, so the file will take up less space or need a lower bitrate when streaming.
Alternatively, you can also achieve better detail reproduction and fewer compression artifacts at the same bitrate. With two equally sized video files, the one in AV1 format should look better.
Meanwhile, NVENC’s performance when compressing to AV1 should be comparable to HEVC, so these benefits are not at the expense of processing speed.
Dual compression engines for faster compression speeds
GeForce RTX 4000 generation graphics cards have one more advantage when compressing to AV1 format. Their GPUs provide two parallel NVENC compression engines. If the video has a higher resolution (4K or higher), these engines can be combined to work on the same video, increasing compression speeds by roughly double compared to a situation where only one engine would be used.
This should be making use of the tile feature in the AV1 format, where video is processed in two (or at least two) tiles forming a single frame. Similarly, on the GeForce RTX 4000 it should also be possible to speed up encoding 2× when using the HEVC format, where the dual encoder can also be used in 4K and higher resolutions (with HEVC the frame is not divided into tiles, but into multiple “slices” instead, but this still allows parallel encoding). The use of this technique does not in any way degrade the compatibility of the video with decoders in devices or video players, everything is within the standards, which allow for multiple tiles or slices per frame.
For the performance tests, we have (and so do you, but beware, this is a large, 60-gigabyte archive) two 30 fps videos in 4K and 8K in Prores422HQ with very high bitrates (805 and 3056 Mb/s).
The output settings for each codec (AV1 and HEVC) are adjusted so that the same bitrate is achieved across different encoders (NVENC and QuickSync). The ICQ of QuickSync is reduced to 12 compared to the default value (26), and according to the bitrate of such video, the bitrate for NVENC is set manually by specifying a limitation to the desired 67 Mbps.
In addition to 3840×2160 px resolution, performance will also be measured at 7680×4320 px (with a bitrate of 158 Mbps).
⠀
