Profile vp9.2 supposedly implemented in Android 7.0 but broken

[Jecht_Sin]

The latest YouTube app (currently version 2.00.19) doesn't play Google's profile vp9.2 HDR videos. Interesting enough, downloading the videos in vp9.2 format from YouTube, using youtube-dl (option -F 337 for the vp9.2 format at 2160p) I get the following:

• Sony's stock Video app plays them in SDR
• Kodi plays them in SDR
• VLC Beta plays them in SDR
• Plex plays them in HDR!!

But the colours in Plex are very washed up. In a video the red colours become pink. Same for blue getting much lighter and all other colours. In another video, what is supposed to be a red button (the one at the end in harmony videos) is instead brown/orange. Chaging to BT.2020 manually it seems to fix it.

When playing the vp9.2 videos in Kodi, pressing "o" in a BT keyboard it shows that it is (rightly?) using the HW accelerated video decoder for vp9 (amc-vp9(HW)):

Now, if it wasn't for Plex playing them in HDR I would have said that Sony/Mediatek still have to implement the profile vp9.2 in Android 7.0 for supported televisions (and ATV2 TVs do support vp9.2 via HW). But Plex does play the videos in HDR! And Kodi does recognize them as vp9 videos. So what is it? The other apps fail to identify them as vp9.2? WHy is Plex doing it at least half right?

Obvioysly this is far from working as designed. As I don't believe we can blame Google on it. It seems to me more like yet another case where Sony and Mediatek should move their.. bottoms and fix it!

[cass_n]

Hi @Jecht_Sin,

If Plex can play the files, it sounds like it's probably an issue with the apps, rather than a hardware issue?

Cheers,
Cass

[Kuschelmonschter]

I actually don't think you can play VP9.2 HDR10 as SDR. IMHO hybrid is only spported with HLG.

[Jecht_Sin]

I don't know.. It seems like the other apps are able to decode the videos, but then they fail to enable the HDR in the TV. I am testing now with the stock Video app few HDR videos downloaded from YouTube. Forcing HDR10 in the "LG SDR vs HDR" video it looks very much like when played in Plex. Same for other videos.

The same HDR videos streamed directly from YouTube, with HDR10 in the TV still forced, look like junk. With the colours all over the place. It seems to me we have 3 cases:

1. Plex recognized it is an HDR video and so tells the TV to switch to HDR
2. The other apps (Sony's own Video app included) still manage to decode the vp9.2 format but "forgetting" to switch the TV to HDR
3. YouTube either doesn't recognize the TV as an HDR TV, or HDR in YouTube for Android TV isn't supported yet. In either case it decides to stream the SDR vp9 version of the videos.

Still I'm quite confident point 2. has to do with the implementation of the Codec for the profile vp9.2. And 3. may still depend on the Codec that fails to say to YouTube "Hey! Look! I can do HDR!!" and so the servers stream a vp9 video instead.

Also I have the feeling (but on this I may be wrong) that all apps fail to get the right Colour Extension. In some cases forcing BT.2020 the colours in HDR look much more like in the SDR version in YouTube. With "Auto"  they may look instead quite washed.