HEVC 10-bit Compressor HW Encode

[Alchemist]

Hi all. Colour me confused.

I am exporting a home movie from our honeymoon using compressor. I initially started out doing it on my iMac Pro in HEVC 10-bit. It was set to take a couple of days as the iMac Pro’s Xeon W doesn’t support hardware encode of HEVC in 10-bit (only 8-bit).

Initially I was set to just let it run but then I remembered that I’d read that the M1 supports hardware encode of 10-bit HEVC. Thing is, after testing it on my M1 MacBook Air, I was presented with something that was also looking like it was going to take multiple days. Can anyone confirm? I am perplexed. This is using the latest version of Apple Compressor and the built in preset for Apple Devices 4K HEVC 10-bit.

Would love some more insight - I’ve searched the web but found scant info on this.

 

[Mr Screech]

Try latest handbrake beta + videotoolbox.
Keep in mind that hardware encoding is nearly always inferior to software encoding.

 

[Alchemist]

Try latest handbrake beta + videotoolbox.
Keep in mind that hardware encoding is nearly always inferior to software encoding.

Thanks. That’s interesting. Two questions:

1. Why would Handbrake support it if Apple’s own Compressor (that has just been updated) not support it? I thought hardware encoding would be independent of the software it’s running through?

2. When you say inferior, do you mean in terms of image quality? I didn’t know that. What’s the reasoning?

 

[Ritsuka]

M1 has got an hardware HEVC 10bit encoder, HandBrake doesn't support it yet. I don't know if Compressor does.

Hardware encoders image quality at the same bitrate is lower because they are implemented in hardware, they need use only a small part of the whole SoC, and once they are shipped they can't be improved, and their target is real-time encoding.
Software encoders are usually better.

 

[Alchemist]

M1 has got an hardware HEVC 10bit encoder, HandBrake doesn't support it yet. I don't know if Compressor does.

Hardware encoders image quality at the same bitrate is lower because they are implemented in hardware, they need use only a small part of the whole SoC, and once they are shipped they can't be improved, and their target is real-time encoding.
Software encoders are usually better.

Thanks for the insight. Unless I am doing something seriously wrong, Compressor does not yet support the M1 HEVC 10-bit encoder. Which is frustrating seeing as it's just been updated. I thought the update was to support the M1 but perhaps I am wrong about that... I found the compressor release notes and it doesn't make any mention of hardware HEVC 10-bit sadly.

As a home movie maker I am interested in decent quality but I'd rather have my encodes take a few hours rather than a few days!

EDIT - I should also add that I left the iMac Pro doing it's thing on the Software encode. Sometime over night, the machine encountered an error and restarted. 24hrs of encoding down the pan!

 

[Mr Screech]

My bad, with hardware encoding I immediately thought about GPU encoding like NVENC.
A CPU with hardware accelerated encoding shouldn't be any different from encoding without acceleration, besides speed.

 

[Ritsuka]

It will still be different. Because an hardware encoder is a complete encoder, it's not something you use to accelerate a software encoder. It's a black block, you pass some frames to it, and it outputs he encoded frames.

@Alchemist: you should try the x265 encoder in HandBrake. It could be faster than Compressor HEVC encoder.

 

[Alchemist]

Hi all. Thought I'd come back and explain some findings. Apple Silicon M1 chips will do a 4k 10-bit HEVC encode using hardware via compressor, but you need to check the 'faster' option under 'Encoder Type'. As default, the Apple Devices 4K HEVC output preset selects the 'Slower (Higher quality)' option.

Took me a few days to pin this information down so I thought it might be of use to someone else out there who is also running into this issue.

Thanks for all your assistance guys - learned a few things along the way.

 

[Peepo]

Hi all. Thought I'd come back and explain some findings. Apple Silicon M1 chips will do a 4k 10-bit HEVC encode using hardware via compressor, but you need to check the 'faster' option under 'Encoder Type'. As default, the Apple Devices 4K HEVC output preset selects the 'Slower (Higher quality)' option.

View attachment 1703286

Took me a few days to pin this information down so I thought it might be of use to someone else out there who is also running into this issue.

Thanks for all your assistance guys - learned a few things along the way.

How much faster is it now? Your original post indicated it was going to take days.

 

[Alchemist]

With hardware encode on my MacBook Air it did the encode in about 2hrs I believe. Would have to check exactly as I left it running, but it is orders of magnitude faster. It also looks better than the same file encoded at 8-bit using hardware encode. You have to look closely, but the qualitative difference is there.

 

[Peepo]

I just did some tests using a short 50 second clip 1080p. With the Apple Devices 4K HEVC 10-Bit setting default to default slower high quality it took about 6 minutes to encode. Flipping it to fast low quality it was like a few seconds and the progress bar just blipped across right away. Was so fast I though it had cached the file or something so I grabbed an entirely different test clip that was never encoded before and was just as fast.

The HEVC 8-bit preset defaults to fast for some reason so it uses hardware by default but for some reason Apple default the 10-bit to the slower software. A 42 second clip at HEVC 8-bit took 4:52 with software and 0:08 with hardware!!!

EDIT - encoding tests for an hour or so makes my MBA M1 warm on bottom for first time LOL!

 

[snakes-]

With compressor for final cut pro you can select 4k 10-bit HEVC. The good thing is compressor shows you on which devices the video is compatible for playback then.

 

[workerbee]

With hardware encode on my MacBook Air it did the encode in about 2hrs I believe. Would have to check exactly as I left it running, but it is orders of magnitude faster. It also looks better than the same file encoded at 8-bit using hardware encode. You have to look closely, but the qualitative difference is there.

Can you compare the resulting files sizes?
I'm still using software x265 encoding because every file I've tried using T2-based hardware encoding so far was either over twice the size or less half the visual quality. If M1 does better in this respect, that'd be quite a selling point for me.

 

[Pskordilis]

Hi all. Thought I'd come back and explain some findings. Apple Silicon M1 chips will do a 4k 10-bit HEVC encode using hardware via compressor, but you need to check the 'faster' option under 'Encoder Type'. As default, the Apple Devices 4K HEVC output preset selects the 'Slower (Higher quality)' option.

View attachment 1703286

Took me a few days to pin this information down so I thought it might be of use to someone else out there who is also running into this issue.

Thanks for all your assistance guys - learned a few things along the way.

The problem with that option is that you can’t go over 50mbs bitrate. i observe that too. i still can’t understand why with slower encoder is too much slower ?