decoding 5k (and higher res) videos

[Stan2292]

tech nood here. i just recently found out my reletively new and moderately powerful i5-11500 can't even decode 5k 2880p video from youttube. the usage shoots up to 100% and the video starts to stutter like crazy. as i understand, 5k videos essentially have twice the pixels as a 4k video, is that correct? why can i watch two 4k videos with ease (less than 10% cpu usage with no hardware acceleration) but can't watch a single 5k video?

[mariushm]

Your video card has hardware decoders in it, specialized for this, the processor only separates the video part from audio, the player 'uploads' the video to the video card, and the video card decodes it.

Depending on your video card, only SOME video formats (some codecs) can be decoded. For example MPEG2, H264 (mpeg-4 avc, used in blurays) , VC1 (microsoft's bluray codec) and VP9 (Google's better than H264 codec) are most likely to be hardware decoded by the video card. Some most recent video cards support AV1 as well.

 

It's not only an issue about what codecs are supported but also resolution and refresh rates ... some codecs are supported up to 8K resolution, some are supported only up to 4K

 

It's possible the 5K video was encoded with a codec like AV1 which your video card maybe can't decode in hardware, so now the CPU has to be used to decode it.

Or, it's possible the video card can decode that codec, but only up to 4K so again, the job of decoding the video falls back to the CPU.

 

If your monitor is smaller than 5K, you add extra work by making the cpu resize the image from 5K to whatever the size is on screen.

 

Right click on the video and select stats for nerds and it will tell you the codecs used.

[Stan2292]

11 minutes ago, mariushm said:

Your video card has hardware decoders in it, specialized for this, the processor only separates the video part from audio, the player 'uploads' the video to the video card, and the video card decodes it.

Depending on your video card, only SOME video formats (some codecs) can be decoded. For example MPEG2, H264 (mpeg-4 avc, used in blurays) , VC1 (microsoft's bluray codec) and VP9 (Google's better than H264 codec) are most likely to be hardware decoded by the video card. Some most recent video cards support AV1 as well.

 

It's not only an issue about what codecs are supported but also resolution and refresh rates ... some codecs are supported up to 8K resolution, some are supported only up to 4K

 

It's possible the 5K video was encoded with a codec like AV1 which your video card maybe can't decode in hardware, so now the CPU has to be used to decode it.

Or, it's possible the video card can decode that codec, but only up to 4K so again, the job of decoding the video falls back to the CPU.

 

If your monitor is smaller than 5K, you add extra work by making the cpu resize the image from 5K to whatever the size is on screen.

 

Right click on the video and select stats for nerds and it will tell you the codecs used.

wait...my graphic card is shit (6gb gtx1060) but i thought the CPU does the heavy lifting when it comes to decoding videos? i mean, obviously you can watch ultra high res videos on laptops/tablets with no discrete GPU right? so how does youtube work when i have hardware acceleration turned off? does it only use GPU? i've always thought it only uses CPU with no hardware acce...? i'm confused...

[mariushm]

Your GTX1060 is NOT shit. It has quite a good hardware decoder.

You can use a tool like DXVA Checker to see what it supports : https://www.majorgeeks.com/files/details/dxva_checker.html

 

Here's what it reports on the old laptop I use on the road :

SD is standard resolution (<720x576 typically, HD is 720p-ish, FHD is full HD as in 1080p, 4K is 4K)

so my integrated graphics supports mpeg2, wmv9, vc1, and h264 up to 4K