HEVC (High-Efficiency Video Coding), also known as H.265 and MPEG-H Part 2, is a new video compression standard that significantly surpasses the efficiency of its precedent, AVC (the Advanced Video Coding), creating files that are up to 40 percent smaller. It ensures the same video quality while consuming less bandwidth or provides greater quality with the same bandwidth.
The better the results, the more resources need to be spent. HEVC is greedy when it comes to computing power demanding a tenfold increase compared to AVC to process files with the same speed. That is the reason why some users who have bought their Macs Pro may be unpleasantly surprised by the amount of time taken by HEVC encoders.
For example, encoding a 3-minute 18-second H.264 clip will take a 2012 Mac Pro about 45 minutes compared to about a minute for a new 2017 iMac Pro given both computers run High Sierra.
As we can see, it’s hardware that plays the main role in ensuring fast encoding. The difference between an old Mac Pro and a new iMac Pro is huge although it is not visible on the outside. iMac’s is all flash-based, and when the need in a 3.5” hard drive is eliminated, the space it used to occupy is effectively used for innovative dual blowers, a massive heatsink, and extra venting. That adds more CPU and GPU power.
Hardware Requirements for Fast HEVC Encoding
Thus, without hardware upgrade or buying a new machine with hardware acceleration for HEVC, it is impossible to achieve acceptable speed.
If purchasing a new computer for HEVC encoding with an optimal price-performance ratio, one should consider a model with 3.0GHz, 8-core Intel Xeon W processor, Turbo Boost up to 4.2GHz, 32GB 2666MHz DDR4 EEC memory and 1TB SSD. A weaker machine will be incapable of running the encoding process of such complexity. The best option currently available is an iMac Pro with 3.0GHz, 10-core Intel Xeon W processor, Turbo Boost up to 4.5GHz, 64GB 2666MHz DDR4 EEC memory and 1TB SSD.
In general, the more cores, the better, but 10 cores are perfectly fine for HEVC. Also, consider upgrading to the Vega 64 graphics card and 64GB RAM, as well as purchasing a Thunderbolt 3 RAID system known for its high speed.
Native Encoding with Compressor 4.4
As for the encoding software, there are several solutions on the market. However, iMacs are equipped with a built-in solution – Compressor 4.4 available only on High Sierra. It is integrated with Final Cut Pro. To access this tool, choose Window > Show Settings and Locations, then click a disclosure triangle next to Apple Devices. Then drag one of the HEVC settings onto the file in the batch area.
To encode a file into HEVC, click Video in the Inspector, and choose Change. Select HEVC from the Compression Type list.
Thus, users who want to do HEVC encoding have no choice but to use modern machines with dedicated H.265 hardware within the system, since the resulting compression requires much processing power.