Chromecast Ultra updated their codec support

[scott.albertine 0]

Previously, Chromecast Ultra only supported H.264 High Profile up to level 4.2. It now (as of a few weeks ago) supports up to level 5.2. I've got some H.264 files that are at level 5.0, that get transcoded when playing on my Chromecast Ultra, even though it now can support them in direct play (without the quality loss and server load). I suspect this is because my Emby for Android app is still telling my Emby server that the maximum supported level for the Chromecast Ultra is 42. I suspect that it's a hardcoded value for that device model, due to it only supporting that level until recently. Can we get an update that allows the newly supported h264 levels to cast appropriately?

 

For reference, here's how I know it's now supported:
https://developers.google.com/cast/docs/media

Edited February 21, 2020 by scott.albertine

[Luke 42083]

Cool, thanks for sharing. I'll try and test this out very soon.

[Luke 42083]

Are you on a 4k display?

[scott.albertine 0]

Yes. And I've confirmed that the Chromecast is outputting a 4k signal (the TV is seeing a 4k signal coming in). The level 5.0 content I've got is all 1080p stuff though, if that matters.

[Luke 42083]

Ok the thing is we're already doing what we're supposed to be doing to detect the supported h264 level and at least on my ultra it's still saying 4.2.

[scott.albertine 0]

Huh. You mean the Chromecast Ultra itself reports, to you, that it can still only take 4.2? Dang. The only evidence I have that 5.2 is now enabled, is the google-official documentation I linked in the original post. They may have goofed in their documentation, or they may not have released the firmware that supports it, or you may not have gotten it, or there may be a new version of Chromecast Ultra hardware that they've stealth released... It could be almost anything.

Only things I can think of to suggest are:

1) You could turn on the "Preview Program" setting on your Ultra, and see if that newer firmware has it (keep in mind, it may take a while for it to get around to updating, take a screenshot of your previous firmware version so you can compare).
2) There's a slim chance that they've added 5.2 support but failed to update the supported level. Can you try casting some level 5.0+ stuff directly to the Chromecast, outside of Emby, to see if the support is actually there? All my 5.0 stuff is contained in .mkv files, and I'm not confident enough at manual transcoding to repackage them into a container the Chromecast can take natively (with the Default Media Receiver app). Alternatively, can you point me to a level 5.0+ sample video file? I googled around and couldn't find anything.
3) We just wait and it eventually updates the supported level and actual support, and it suddenly just starts working.

I appreciate the quick responses, and I understand if this is a "leave it and it'll take care of itself" item.

[Luke 42083]

Well another way to test support is to temporarily restrict transcoding access from the emby user. But keep in mind just because it starts playing doesn't necessarily prove anything. You really need to see that it plays smoothly through the whole thing.

[scott.albertine 0]

...It works. I've got direct streaming to a Chromecast Ultra, of H264, level 5.0 content, as reported in the Emby server dashboard. I've tried it with multiple different files, both TV and movies, animated and live action, and it works great. I also let one of them play out for 10 minutes, with no observed hitching or dropped frames. Is that sufficient, or do I need to watch a full 2-hour movie to know? What effects should I be looking for, other than video stutter? I also skipped around a bunch in both files, and performance was great.

I re-enabled transcoding for that user, and am now seeing it transcode due "video level not supported". Same file, same server, same Chromecast.

My chromecast version is 1.42.183786. 

 

This does provide a work-around, which is nice, and basically solves my issue, but I'm curious why the Chromecast is reporting level 4.2 when it can handle more than that? Is there an updated reporting API for the new versions?

[Luke 42083]

 

 

but I'm curious why the Chromecast is reporting level 4.2 when it can handle more than that?

I don't know yet, still trying to get to the bottom of  that. Thanks for testing.