Any MV-HEVC encoders?

[rwill]

Well if one does not need inter layer prediction it is pretty easy to merge two HEVC streams into one MV-HEVC stream...

Doing inter layer is pretty easy too if one can modify the reference picture list setup of layer > 0.

I wonder why there is no patch for x265 yet.

[benwaggoner]

Originally Posted by rwill

Well if one does not need inter layer prediction it is pretty easy to merge two HEVC streams into one MV-HEVC stream...

Doing inter layer is pretty easy too if one can modify the reference picture list setup of layer > 0

And interlayer is pretty important! That gives ~20% instead of 100% added bitrate for stereo 3D.

I wonder why there is no patch for x265 yet.

Why? It's work that engineers would have to do instead of doing something else.

Among other things, x265 would need a way to input multiple synchronized sources to encode from. Getting interlayer working, including rate control. Getting all the signaling working and tested. The R&D is much more D than R, but it's still work for multiple developers for multiple months.

[kagami.h]

Ben, could you please look at https://forum.doom9.org/showthread.p...69#post1997769
I made a post here, but then it disappeared for some reason.

[rwill]

Originally Posted by benwaggoner

And interlayer is pretty important! That gives ~20% instead of 100% added bitrate for stereo 3D.

Well from my tests the second layer is more like 40%-70% of the first layer, depending on how clean the content is or if there is grain etc. For real 3D Cinema content anyway. Sure one can make the second view a little worse quality but this was not accepted here.

Originally Posted by benwaggoner

Why? It's work that engineers would have to do instead of doing something else.

Among other things, x265 would need a way to input multiple synchronized sources to encode from. Getting interlayer working, including rate control. Getting all the signaling working and tested. The R&D is much more D than R, but it's still work for multiple developers for multiple months.

Strange, I know of one HEVC production encoder that got extended to MV-HEVC where it took a single engineer around 2 weeks, including changing certain parts of the reference decoder for testing.

[kagami.h]

Originally Posted by rwill

Well from my tests the second layer is more like 40%-70% of the first layer, depending on how clean the content is or if there is grain etc. For real 3D Cinema content anyway. Sure one can make the second view a little worse quality but this was not accepted here.

Right, they report 32% savings for MV-HEVC versus simulcast in the paper.

[MSwanson]

Thought I'd weigh-in on some of this. For context, I've written a bit about what Apple is doing with MV-HEVC here: https://blog.mikeswanson.com/post/74.../spatial-video

Also, the Apple streams I've looked at show ~50% savings for the second layer. Interestingly, this doesn't appear to be the same encoder as what is currently provided in AVFoundation. Or at least it's a much more customized/future version. As far as I can tell, AVFoundation (Mac, iPhone, and Vision Pro) is encoding two separate HEVC streams and stitching them together with no inherent savings or inter-layer prediction. The AVFoundation encoder also doesn't seem to support multi-pass encoding or rate control beyond simple bitrate averages. I'm hoping that all of this improves with an upcoming release or perhaps at WWDC24.

[benwaggoner]

Originally Posted by MSwanson

Thought I'd weigh-in on some of this. For context, I've written a bit about what Apple is doing with MV-HEVC here: https://blog.mikeswanson.com/post/74.../spatial-video

Also, the Apple streams I've looked at show ~50% savings for the second layer. Interestingly, this doesn't appear to be the same encoder as what is currently provided in AVFoundation. Or at least it's a much more customized/future version. As far as I can tell, AVFoundation (Mac, iPhone, and Vision Pro) is encoding two separate HEVC streams and stitching them together with no inherent savings or inter-layer prediction. The AVFoundation encoder also doesn't seem to support multi-pass encoding or rate control beyond simple bitrate averages. I'm hoping that all of this improves with an upcoming release or perhaps at WWDC24.

Yeah, the 32% efficiency improvement always seemed much lower than what should be achievable with a perceptually optimized encode; most times the eyes look pretty similar, with big regions often identical.

I'm pleased but unsurprised Apple has done better.