MPB 13" Early 2015 - 4K @60fps works on Vimeo but not on YouTube (Google Chrome & FireFox)

[ccrary]

Hi,

I have an Early 2015 13" MBP Retina and I cannot get 4K @60fps streaming on YouTube within the most up-to-date versions of Google Chrome or FireFox without almost all frames being dropped. The external monitor that I am using is a Dell U2720Q, and the specs for my MBP are attached in the image immediately below. I have an internet download speed of 300+ Mbps.

From my research thus far, it seems like my MBP should be capable of driving 4K @60FPS, and it seems like this works on websites like Vimeo, but I cannot seem to figure out how to get it to function on YouTube.

As an example of a video that seems to stream correctly at 4K 60fps on Vimeo, see the first link given below. As an example of a video that cannot stream correctly at 4K 60fps on YouTube, see the second link given below. (For both videos, I have ensured that I correctly changed the resolution settings within the video players to be 4K, not anything else.)

[1]

[2]

Overall, with the hope that my issues may be fixed, I have tried toggling the hardware acceleration features of Google Chrome and FireFox, I have tried putting my MBP into clamshell mode, I have tried scaling the display within System Preferences to be 4K and to 1K, I have tried closing all other applications, etc.

I understand that there are encoding issues regarding Safari and YouTube, but it seems like this shouldn't be a problem for Chrome or FireFox.

Any help would be much, much appreciated.

Thank you,
Chris

 

[ccrary]

Bump.

 

[coffeeplease]

Vimeo uses H.264 codec while YouTube uses VP9. Your 2015 13" MBP has Broadwell Intel chip, which has hardware decoding support for H.264 but not VP9. When you play YouTube videos, it's software decoded on the CPU and is very intensive for a regular 4K video, let alone a 4K 60 FPS video.

 

[ccrary]

Ah, I see! Thank you, @coffeeplease! And hardware support for VP9 is to be added in the Big Sur update coming within the few months, or is this an inherent limitation of the Intel chip?

 

[coffeeplease]

Ah, I see! Thank you, @coffeeplease! And hardware support for VP9 is to be added in the Big Sur update coming within the few months?

Hardware decoding for VP9 was always on the newer machines, just Apple never enabled it. Apple has enabled it in Big Sur. I don't believe the Broadwell Intel chip has hardware decoding for VP9, but users with older MacBooks are reporting that playback is smooth, see this thread.

 

[ccrary]

After reading through the entire attached thread, it does seem plausible that Apple somehow enabled VP9 support within the Broadwell chips through Big Sur, but I will probably wait for an official release of Big Sur before I test it. Thanks so much for sharing!

 

[ilikewhey]

just tried it on my 13inch 2015, once the video loaded(i'm on wifi ac so it was constantly buffering) it was playing at the same speed as my 2018 mbp 15inch. however it was very taxing on the cpu. do you only have the youtube open?

 

[ccrary]

Yes, while testing that, I only had YouTube open through either Google Chrome or FireFox.

Are you using the latest beta of the new Big Sur MacOS update for your testing, or are you using a previous version of MacOS? It seems that there is no hardware support for the VP9 or AV1 encodings (of which VP9 should be used by YouTube for that video) on previous MacOS versions.

 

[ilikewhey]

i'm on mojave, the biggest struggle was just loading the video, and waiting for the cpu to cool a bit, after that i can play 10-15 seconds before the cpu heats up again. but during that 10-15 sec the video felt 60hz at 4k compare to my 2018 mbp.

 

[ccrary]

Gotcha, well I can only get like half a second of 4K @60fps before my video completely freezes and drops hundreds of frames. Hopefully Big Sur will ultimately fix this, as alluded to in the following thread previously linked above by @coffeeplease.

macOS 11 Big Sur Safari YouTube 4K HDR VP9 support

Safari and Webkit New Features in macOS Big Sur 11 beta 4 Support for 4K HDR playback of YouTube videos. (64824895) https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11-beta-release-notes/ Has anyone tried this? I assume this is available to any Mac that can run Big...

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