libaom AV1 decoder failed due to CONFIG_REALTIME_ONLY is 1

[Wei Fei]

I found libaom AV1 decoder failed with the latest Chrome version(m98), due to CONFIG_REALTIME_ONLY is 1 in aom_config.h file ( https://chromium.googlesource.com/chromium/src/third_party/+/refs/heads/main/libaom/source/config/linux/x64/config/aom_config.h)
With CONFIG_REALTIME_ONLY turned on, some AV1 features are disabled. I have checked other libaom release version, CONFIG_REALTIME_ONLY is actually turned off.

My question is why CONFIG_REALTIME_ONLY is turn on for WebRTC? Considering performance? Will It be fixed by turned off CONFIG_REALTIME_ONLY? 

Thanks.

[Johann Koenig]

On Fri, Mar 4, 2022 at 7:22 AM Wei Fei <feiwe...@gmail.com> wrote:
> I found libaom AV1 decoder failed with the latest Chrome version(m98), due to CONFIG_REALTIME_ONLY is 1 in aom_config.h file ( https://chromium.googlesource.com/chromium/src/third_party/+/refs/heads/main/libaom/source/config/linux/x64/config/aom_config.h)
> With CONFIG_REALTIME_ONLY turned on, some AV1 features are disabled. I have checked other libaom release version, CONFIG_REALTIME_ONLY is actually turned off.

Can you be more specific about the failure? There have been issues
where CONFIG_REALTIME_ONLY was missing some features
(https://bugs.chromium.org/p/aomedia/issues/detail?id=3077) but they
were generally found and fixed quickly. It may be best to file a bug
on that tracker: https://bugs.chromium.org/p/aomedia/issues/entry

> My question is why CONFIG_REALTIME_ONLY is turn on for WebRTC? Considering performance? Will It be fixed by turned off CONFIG_REALTIME_ONLY?

As a build-time option CONFIG_REALTIME_ONLY generally has more to do
with library size considerations. You should be able to get identical
results with it disabled as long as you set the encoding parameters
the same.

[feiwei]

Understood AV1 encoder is configured as realtime mode, but it is unreasonable to configure AV1 decoder as realtime mode, The decoder should support full of the features defined by AV1 spec.

Thanks.

[feiwei]

Already reported as an issue. It was said libaom decoder will be eventually replaced with dav1d, but not scheduled yet.

https://bugs.chromium.org/p/chromium/issues/detail?id=1302623#c5

On Tue, Mar 22, 2022 at 5:27 PM Johann Koenig <johann...@google.com> wrote:

On Tue, Mar 22, 2022, 17:07 feiwei <feiwe...@gmail.com> wrote:

Understood AV1 encoder is configured as realtime mode, but it is unreasonable to configure AV1 decoder as realtime mode, The decoder should support full of the features defined by AV1 spec.

Correct. The decoder should accept all streams. If there is a feature that does not work in Chrome please file a bug with libaom:

https://bugs.chromium.org/p/aomedia/issues/entry

From your comments here I can't tell where your error is coming from.