profile 1 features

[Ronald S. Bultje]

Hello guys,

so, it looks like profile 1 was recently finalized. I'm trying to support it correctly in FFmpeg. Two questions:

- how is RGB channel order defined? I don't see test samples and RGB is not mentioned in the source, other than the colorspace entry in the header. H264/HEVC uses GBR, so for now I've assumed that's identical in VP9, but I'd like to make sure. Could you guys add a 1-2 frame sample to the conformance suite to make this more obvious?

- where did alpha channel go?

As for profile 2/3, is it stable yet? Are the main differences between profile 0/1 and 2/3 (in terms of how many bits per coefficient, clipping behaviour, etc.) documented somewhere, or should I go by the source?

I a profile 4 and up planned? I see extension bits in the header so I'm wondering what's in store.

Thanks,

Ronald

[Aℓex Converse]

On Thu, Apr 30, 2015 at 11:29 PM, Ronald S. Bultje <rsbu...@gmail.com> wrote:

Hello guys,

Hi,

 

so, it looks like profile 1 was recently finalized. I'm trying to support it correctly in FFmpeg. Two questions:

- how is RGB channel order defined? I don't see test samples and RGB is not mentioned in the source, other than the colorspace entry in the header. H264/HEVC uses GBR, so for now I've assumed that's identical in VP9, but I'd like to make sure. Could you guys add a 1-2 frame sample to the conformance suite to make this more obvious?

The RGB channel order never got formally defined. 

- where did alpha channel go?

It was removed because:

• It was broken in a whole host of ways. 
• Nobody was using the WebM container level alpha channel for VP8. 
• The reason nobody was using it didn't appear to be related to coding efficiency. 

As for profile 2/3, is it stable yet? Are the main differences between profile 0/1 and 2/3 (in terms of how many bits per coefficient, clipping behaviour, etc.) documented somewhere, or should I go by the source?

I a profile 4 and up planned? I see extension bits in the header so I'm wondering what's in store.

Thanks,

Ronald

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[Ronald S. Bultje]

Hi Alex,

On Tue, May 5, 2015 at 7:32 AM, 'Aℓex Converse' via Codec Developers <codec...@webmproject.org> wrote:

On Thu, Apr 30, 2015 at 11:29 PM, Ronald S. Bultje <rsbu...@gmail.com> wrote:

Hello guys,

Hi,

 

so, it looks like profile 1 was recently finalized. I'm trying to support it correctly in FFmpeg. Two questions:

- how is RGB channel order defined? I don't see test samples and RGB is not mentioned in the source, other than the colorspace entry in the header. H264/HEVC uses GBR, so for now I've assumed that's identical in VP9, but I'd like to make sure. Could you guys add a 1-2 frame sample to the conformance suite to make this more obvious?

The RGB channel order never got formally defined.

So, can I ask you guys to formally define it? I would personally propose GBR since that's identical to other codecs, but anything is better than not defining it... As said, a sample in the conformance suite (to visually confirm the ordering, and because the header is slightly different for RGB vs. YUV - so full code coverage) would be helpful.

Thanks,

Ronald