VP9 Status Update

[Paul Wilkins]

VP9 progress update.

I just thought I would give everyone an update on what the team have been up to for the last few weeks since the official freeze of the VP9 bitstream mid June.

Encoder speed improvements.

We have been working hard to improve the encoder speed / quality trade off. This involves a mixture of code optimization, code clean up and algorithmic experiments that limit the number of modes etc. that are searched.  Most of the experiments are controlled by flags which are turned on and off using different command line speed settings.

The quality/speed settings used for all previously quoted results were “--good --cpu-used=0” so the results below are compared to this baseline, using a build just before the freeze.

Command line setting Speedup Quality impact

--good --cpu-used=0 ~x6.5 ~ +1% !

--good --cpu-used=1 ~x21 ~ -5.5%

--good --cpu-used=2 ~x48 ~ -12%

Obviously our aim is to continue to increase the speed multiplier for all settings and decrease the quality penalty for speeds 1 and 2. Stay tuned.....

Decoder speed

On the decoder side we have recently started optimizing for arm and so far have about a x2 speed up. For Intel architectures we have improved decode speed by about x1.3. Plenty more to come!

Bug fixes

I also want to draw your attention to the following bugs that have identified and fixed since the formal freeze. All these have been incorporated into the Chrome M29 branch.

Loop filter edge cases.

Change-Id: Ib2fbbcb40166e90af31b1a0e13b85b68c226cbd3

Change-Id: I4a0b65056c64f97478827c2ff41e0914fc7779d0

Bug in prediction context for compound reference frame.

Change-Id: I4cc00b761e9473f92f180a9fc3a0c607f0aaae56

Border extension when using reference buffers at different scales.

Change-Id: I5184443e6731cd6721fc6a5d430a53e7d91b4f7e

Change-Id: I02d15bfde4d926b50a4e58b393d8c4062d1be70f

Key frame context initialization (with scalable coding)

Change-Id: I08b53e3a30c8289491212311682ff1b8028cff6c

Define fixed quant tables to avoid possible architecture dependant rounding issues.

Change-Id: I6ed260aebd49feb4cfb5596a5370c44be5f72167

Documentation.

We now have someone working full time on properly documenting the bitstream and will hopefully make this a priority in the coming weeks.

Regards,

Paul Wilkins

[Pieter Kapsenberg]

Is there a plan and/or timeline to support segmentation in the encoder?

[nob...@gmail.com]

Are there any combinations of parameters that yield such a speed boost for single-pass encoding?

I'm attempting to encode a VGA stream in real-time with VP9 and it takes ~2 secs per frame on a high-end desktop.

On Wednesday, July 24, 2013 1:32:22 PM UTC-7, Paul Wilkins wrote:

[James Zern]

On Wed, Jul 31, 2013 at 2:59 PM, <nob...@gmail.com> wrote:
> Are there any combinations of parameters that yield such a speed boost for
> single-pass encoding?
>

Not yet. The first release of vp9 was targeted at 2-pass encoding.
Realtime will likely come next, but currently all 1-pass can be viewed
as unstable.

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[Aaz MP]

четверг, 25 июля 2013 г., 0:32:22 UTC+4 пользователь Paul Wilkins написал:

Documentation.

We now have someone working full time on properly documenting the bitstream and will hopefully make this a priority in the coming weeks.

Regards,

Paul Wilkins

So? Where is documentation?

[Aaz MP]

Any updates in past weeks?)