<prompt> "Talk to me about it."
 

<claude> Good question, because the honest answer has layers, and most of the "8K" in the ads lives in only one of them.

What's real: the decoder. The RK3588's video engine (RKVDEC2) really does decode 8K: HEVC and VP9 at 8K@60, H.264 and AV1 at 8K@30, in silicon. That's not marketing. It's the same block Deep Ink talks to for our 4K HDR work, and 8K is just more macroblocks through the same pipe. So "8K video decoding" is a true statement about the chip.

Where it thins out: the display. The VOP2 display controller's big port (VP0) tops out at 8K@30 or 4K@120, and here's the nugget: those are the same number. 7680×4320×30 = 995 million pixels per second; 3840×2160×120 = 995 million. The 4K@120 we fought for this month (the dclk patch, the FRL link-up on rkr7.2, the vp0 done bit timeout at the edge) is literally the chip at its 8K@30 ceiling. There is no 8K@60 output from this silicon, whatever the HDMI 2.1 badge implies. 8K@30 at 4:2:0 over a 48G cable to an 8K TV is the whole display story, and nothing in mainline Linux drives an 8K mode on VOP2 today.

Where it falls apart: everything between decode and glass. A decoded 8K 10-bit frame is about 62 MB; a reference buffer set is half a gigabyte, so CMA would need to go to a gigabyte-plus just to open the file. Then someone has to get 33 million pixels per frame onto the screen. The Mali-G610 compositing a full 8K desktop through Mutter would be a slideshow. The only sane path is the one TV boxes use: the decoder hands frames straight to a VOP video plane and the GPU never touches them. That's a Kodi/direct-scanout architecture, not a GNOME desktop. And there's no browser path at all: YouTube's 8K is VP9/AV1, and we already know what the browsers do with those on this chip.

Who it's really for. Rockchip's 8K line is aimed at media-box and signage makers, who get one 8K TV, one app, direct plane output, and no desktop. For a desktop distro it's a spec-sheet number, not a feature.

What's honest to say for Plaid: "decodes 8K; displays 4K at up to 120 Hz." Playing an 8K HEVC file in mpv, hardware-decoded, scaled down to your 4K panel, is a thing this box can do, and that's the version that's true in your living room. "8K desktop" is a mirage, and that's the brand line.

If you want numbers rather than theory, I can make an 8K HEVC clip and measure what mpv + rkmpp does with it on the Plaid: decode rate, CPU, whether the 512 MB CMA even lets it open. That would give the website a measured sentence instead of a claim.

<prompt> "Ok, that's where it becomes a development board... We can do it... now you make it work"


<claude> Here's what "8K" turned out to mean, measured rather than argued.
 

The decoder is real. With frames left on the GPU, the VPU chewed through 8K30 HEVC at 55.8 fps, one decoder interrupt per frame, nearly double real time. Rockchip's "8K@60 decode" is silicon, not a brochure. And CMA never moved: the driver uses its own buffer pool, so the 1 G bump won't change decode (fine to reboot whenever; it only matters if an 8K output ever exists).

The screen is the problem, and it's the Mali blob's desktop, not the chip. The stutter you saw was the only on-screen hardware path, copy-back, at 11 fps, because shoving 50 MB per frame through the CPU costs ~90 ms. The fast path, zero-copy, dies before the first frame: mpv needs a VA display tied to its GL context, and under Mutter-on-libmali there's no way to get one. The compositor only offers dmabuf protocol v3 and no wl_drm (I read the Wayland registry to confirm), libva's Wayland backend needs v4, and XWayland has no accelerated EGL on the blob. Behind that door is the GR88 wall Firefox hit. Also a trap: mpv 0.41 tries Vulkan first, fails on the blob, and silently goes software unless told --gpu-api=opengl; your shipped mpv.conf effectively runs copy-back for everything.

The honest website line: "decodes 8K; displays 4K at up to 120 Hz." And a nice symmetry for the curious: 8K30 and 4K120 are the same 995 Mpx/s, which is VOP2's ceiling. No 8K60 output exists on this chip, HDMI 2.1 badge or not.

Routes to actually playing 8K, ranked: a ~10-line mpv patch to open the VA display from the render node directly, then PC's R16 trick for the import (same problem, same fix as Firefox); or the Mesa/panthor stack, where Mutter offers v5 and Mesa imports everything, so it very likely just works. One more point for mainline.

 

Built Finagled Measured Rendered Verdict
Claude Fable 5

I was watching Weezer and it came up

defcom5-rockchip

I recommend using "caveman ultra" skill to reduce the barfed out walls of slop