Puget Systems print logo


Read this article at https://www.pugetsystems.com/guides/1211
Article Thumbnail

Video: H.264 Hardware Acceleration in Adobe Media Encoder - Good or Bad?

Written on August 2, 2018 by Matt Bach

Video Summary

In the update notes for Media Encoder and Premiere Pro CC 2018, Adobe has listed support for "hardware accelerated" when exporting to H.264 and H.265 when exporting. What this feature does is to utilize the Quicksync functionality built into some Intel CPUs in order to dramatically decrease the time it takes to export to these codecs. At first glace, this feature provides a huge boost in performance for many users, but unfortunately it is not perfect.

The first issue is that it requires a CPU that supports Quicksync (a list can be found here) and you also have to make sure the onboard graphics on your motherboard is enabled. You do not need to have a monitor plugged into the onboard graphics, it just needs to be on so that Quicksync can be active. The problem is that most of the best CPUs for Premiere Pro and Media Encoder (the Intel X-series) do not support Quicksync so many high-end professionals simply won't be able to take advantage of it.

The second issue with hardware accelerated encoding is that it is not the same quality as using the normal "Software only" mode. In fact, in our testing we found that the target bitrate was not always being met when using hardware acceleration. And even when it was, the quality was still lower than "Software only" mode. The odd thing was that when the bitrate was being matched, the time to export was identical in both modes - so we only saw a performance gain when the final exported file was at a lower actual bitrate.

If you are simply looking for the fastest encoding times (proxy generation, etc.) of H.264/H.265, hardware acceleration is a pretty neat and useful feature. If quality is a concern, however, it may not be worth the loss in quality unless you are on extremely tight deadlines.

H.264 Match Source - High Bitrate

Software Only
33 Sec export - 23.8MB exported file
[View Full Image]

Hardware Accelerated
33 Sec export - 23.9MB exported file
[View Full Image]

H.264 High Quality 2160p 4K

Software Only
58 Sec export - 183.4MB exported file
[View Full Image]

Hardware Accelerated
31 Sec export - 34.4MB exported file
[View Full Image]

Tags: Media Encoder, Quicksync, Hardware Acceleration.H.264

I can not believe Adobe never warned about this. So ridiculously unprofessional. Nice findings, Puget, guess I'll go and disable this.

Posted on 2018-08-02 18:23:18

I wouldn't jump to conclusions so quickly; encoding hardware acceleration is an extremely valuable feature that Adobe UNDER-played at launch. These results are not comprehensive, though a helpful start - and besides the time factor (are you in a rush or not), another important factor is simply whether or not you're pixel peeping down to that level. Whether anybody would ever notice is an unavoidable question.

And this also focuses in on codec encoding acceleration even though such nominal degradation caused by hardware acceleration has also loomed over the usual kind of hardware acceleration from GPUs that Puget Systems actually never attacks, yet always incorporates into its tests. Put another way, there's prior evidence widely discussed -- again, of tiny differences -- showing that GPUs encode worse than software-only.

If there's any work to be done first, it's the target bitrate issue that appears to be a bug in the Adobe encoding hardware acceleration design. By getting the target bitrate right, these apples-to-oranges comparisons would become more apples-to-apples: comparing hardware versus software codec encoding with the same RESULTANT bitrate.

More here: www.focuspulling.com/cc2018

Posted on 2018-08-02 18:34:49

Sure, I can see this feature being useful. I'm mostly just disappointed that Adobe never acknowledged this in the patch notes or Media Encoder's UI itself. Without prior knowledge of this, it might appear as if you should expect same quality from both options. Personally I don't mind waiting a bit longer, for a better quality off of similar bitrate and file size. I mostly render After Effects projects, so I don't think I'm affected by faster H.264 encoding as much as Premiere.

Posted on 2018-08-02 20:13:37

I just want to point out that the "H.264 Match Source - High Bitrate" preset did actually use the correct bitrate in both "Software Only" and "Hardware Accelerated" mode. So that test is definitely an apples-to-apples comparison and the quality difference is pretty easy to see. Interestingly, that is also the one where we didn't see any performance gain at all. It makes me wonder how much of the performance gain people talk about is actually due to Media Encoder not actually setting the bitrate correctly so people are actually comparing two completely different export settings without being aware of it.

Posted on 2018-08-02 20:18:19

Good point; I'm getting different results than yours, though, when it comes to achieving a high target bitrate that's equivalent between hardware vs. software codec encoding, but vastly faster codec encoding in hardware mode. Pixel peeping down to magna-zoom levels can vary greatly depending on the footage, but that's where I'm headed next. I don't think it's fair to be conclusive at this point -- yet Adobe itself doesn't seem to care either, having totally buried this feature launch (purposefully?).

Posted on 2018-08-02 20:41:42

Quicksync also doesn't stand on its own 2 feet next to AME or NVenc offerings in hardware encoding. So the entire concept of hardware support is still amazing as you suggested.

Posted on 2019-03-05 11:56:22

It is something that people who are familiar with encoding have known for a very long time. Have you ever looked at the doom9.org forums?
Anyone who uses x264 / x265 / ffmpeg knows the hardware encoders are crap. Quicksync is better than NVENC and AMD's encoder, but all 3 hw encoders are total crap, worsening with lower bitrates especially for difficult scenes. Unfortunately so few professional videographers and editors realize this.

Posted on 2018-08-19 16:38:59

You're being unreasonably (and transparently) dramatic, proclaiming that few of us know this, and that everyone in the world would compare the differences and conclude that hardware-encoded exports "are total crap." Even the flawed pixel-peeping referenced in this article here, is barely enough reason to forego the dramatic speed improvements for high-productivity environments. The differences significantly narrow when you use common codecs like XAVC or other typical compression formats that already compromise image quality -- normal folks live in a world of trade-offs.

Posted on 2018-08-19 19:56:47

One can only speculate as to why did Adobe release this now and at the same time keep it under wraps? This seems like a significant change indeed and the performance cannot really go unnoticed, bar the bitrate settings.
Talking about bitrate, while can understand the quality loss due to hardware encoding, be it QuickSync or NVENC, not sure about the results for Match Source Rate target 10Mbps, this is usually HD quality preset. Being 4K exports isn't the target supposed to be (a lot) higher?
There is a video from the guys at GamersNexus testing a 1080p video and same as here, HW encoding time is almost identical compared to SW only encoding - thing is that was a simple timeline, with no effects. You are testing with Red footage compared to 1080p, does this point to QuickSync being more efficient at higher bitrates, regardless of resolution?

GN also make a point that the digital artifacts / loss of quality may not be so important for some people and this feature can potentially make a significant impact on the decision to purchase a certain hardware configuration - for example, the 8700K will get a lot closer to the Intel-X and TR, if only in terms of exports.

On another point, Nvidia, of course CUDA still plays a role here and it's not just for encoding. Have you noticed any changes in the dGPU utilization when the iGPU is enabled as well, either during exports or regular usage in Premiere? It may seem like 2 competing resources for the same task, so it'd be interesting to gauge the impact on each other.

Lastly, wonder if the likes of FCP, Vegas or other NLE have this QuickSync acceleration feature enabled already.

Thank you again.

Posted on 2018-08-03 03:23:20

GN? No idea what that is.

Posted on 2018-08-03 04:56:22

as far as i know FCP uses quicksync for decode & encode on mac's to achieve max speed on lower end cpu's

Posted on 2018-08-06 08:40:04

For Nvidia, the default and preferred method is to use NVENC, which is the fixed function encoder block and does not use CUDA at all. The fully accelerated encoders in nvidia, intel and gpu do not use the GPU's shaders, they are relegated only to the fixed function encoding block.

Posted on 2018-08-19 16:41:18

A couple considerations:
1) Did you compare more than just the first frame in the video to see if the quality delta exists throughout the clip? In my own testing, I found comparing a single frame can be misleading with these Long GOP codecs. Frame to frame, the winner can flip back and forth throughout the clip.

2) For your second test you seemed to have encountered a bug with QuickSync encoding at high bitrates. If you chose a preset such at YouTube 4K, which targets 40Mbps, you'll see that the export file is much larger and better in quality. After some quick googling there might be a bug/artificial limit of ~65Mbps with QS but I haven't tested that myself.

Posted on 2018-08-05 20:52:52

I hope someone from Puget Systems will reply to your points.

They both might have merit.

Posted on 2018-08-16 05:19:03
Lars Emanuelsson

Still no answer. Maby a bitrate under 65Mbps did the trick?
I'm about to build a 4k video editing pc and try to find more information about this since it will save a lot of money on the CPU.
I can't find any other report about quality loss when using Igpu hardware encoding so I guess the exaple in this article was just bad luck.

Posted on 2018-10-31 21:17:30

Personally I'm resolved to completely ignore these results and keep on the lookout for any other evidence. So far, nothing besides microscopic pixel-peeping.

Posted on 2018-10-31 21:19:43

Ryzen Or Intel Best For Premiere pro CC ??

recommend Best Cpu For Edting My pc rig Ryzen 1700 lagging For HD
Pls Help ME

Posted on 2018-08-10 14:41:46
Nate Porter

I'd love to see an analysis on davinci resolve's hardware acceleration for encoding now that it supports it as of 15.2

Posted on 2018-12-04 16:04:03

does it makes any difference when you export for youtube as youtube re encodes videos at even lower bitrates ? has someone downloaded youtube videos to check bitrates ?

Posted on 2019-01-07 10:48:44

I'm actually working on an update to this right now since the latest versions of Premiere Pro and Media Encoder are supposed to have improvements for H.264 Quicksync hardware acceleration. As a part of it I was going to do a Youtube upload and grab screenshots directly from Youtube to compare. As long as I don't run into a complication (or if the updates made it so that the quality loss is smaller than it was in this testing), hopefully that will work.

Posted on 2019-01-08 21:06:25
Ian Green

I have Handbrake which is open source and it can encode anything on hand fairly good

Posted on 2019-02-28 03:27:30
J Dor

In the light of the new Adobe 2019 NAB update, has this issue been resolved, or is hardware acceleration still much poorer, not respecting the target bitrate etc.?

Posted on 2019-04-04 07:31:43

Hardware acceleration at rendering H.265 and H.264 has never been "much poorer" and this flawed comparison is indeed quite outdated now.

Posted on 2019-04-04 16:52:56

We have found that much of the quality issue with Hardware Accelerated encoding is due to it being limited to ~60mbps. If you try to set it higher than that (which the "H.264 High Quality 2160p 4K" preset does), Premiere Pro and Media Encoder don't follow the target bitrate and revert back to a very low bitrate. This explains both the low quality and faster performance found in our testing.

From everything I've tried, it looks like at least in Premiere Pro and AME, hardware accelerated encoding isn't that much faster if you have a relatively high-end CPU like a Core i9. Lower-end CPUs should still see a decent performance benefit, however.

Posted on 2019-04-04 17:03:22

Appreciate this updated information, if it is not tentative and is proven by lab results -- but 60 Mbps is a very high threshold for the alleged problem, that implicitly defies the whole point of using the H.264 and especially H.265 codecs designed for portability and efficiency. Almost all of the UHD presets offered by Adobe (e.g., Vimeo) do not come near 60 Mbps (e.g., 48 Mbps) and that is the real-world use case, where the hardware acceleration is warmly welcomed and proven to work well.

Posted on 2019-04-04 17:12:01