[xservzeroman]

Stacked on #128. Submodule third-party/chiaki-ng points at chiaki-ng-mooncast perf/decode-latency @ 227e79dd (two commits on top of c5fa7fad).

Saleh: PXPlay shows decode < 1 ms on the Odin 2 Portal (Snapdragon 8 Gen 2, "kalama"); MoonCast showed up to 5 ms on the same device and network.

What the numbers measured

• MoonCast before: queued to MediaCodec → output buffer dequeued, but taken after the frame was handed to the screen (releaseOutputBuffer / …AtTime), smoothed over about 20 frames.
• PXPlay most likely measures queued → output available.

What I found on the Odin

• The device has c2.qti.hevc.decoder and c2.qti.hevc.decoder.low_latency (also AVC). createDecoderByType always picked the default one.
• The low-latency instance accepts all our keys (level 0). On a mostly still PS5 home screen, though, it only saved about 0.2 ms over the default.
• Diagnostics: frames were ~600–2000 bytes. Feeding a frame (dequeue input + copy + queue) takes 0.4–0.6 ms, so the codec2 pipeline itself costs ~2–3 ms even for tiny frames.
• A plain releaseOutputBuffer(render) never fired the frame-rendered callback on this codec2 decoder. Releasing with a timestamp (now) does, and shows the frame just as soon.

Changes (chiaki-ng-mooncast fd5b9a23 + 227e79dd)

1. Decoder Low / Ultra use the <name>.low_latency (Qualcomm) or .lowlatency (MediaTek) instance when the device has one. Standard keeps the default.
2. Qualcomm: operating-rate 32767.
3. Output thread at priority -8 (logged: "output thread at priority -8").
4. Decode = queued → decoded, measured before release.
5. New render wait = decoded → on screen, via AMediaCodec_setOnFrameRenderedCallback (Android 13+). Lowest delay now releases with releaseOutputBufferAtTime(now) so it reports.
6. Both are shown in Detailed stats ("decode (queued to decoded)", "render wait (decoded to on screen)") and logged as stats … decode= render=. A diagnostics line is logged every 1800 frames.

Measurements (Odin 2 Portal, PS5-423, 1080p60 HEVC, home screen ~0.3 Mbps, 30 s each, test268)

Decoder	Frame pacing	decoder instance	decode	render wait
Standard	Lowest delay	c2.qti.hevc.decoder	3.92 ms	0.20 ms
Low	Lowest delay	.low_latency	3.72 ms	0.22 ms
Ultra	Lowest delay	.low_latency + sw fences	2.77 ms	0.22 ms
Low	Balanced	.low_latency	3.67 ms	7.40 ms
Low	Smoothest	.low_latency	3.65 ms	12.33 ms
Ultra	Balanced	.low_latency	2.78 ms	8.30 ms

• Before: test237 (2026-10-21) measured 7.4 / 8.5 / 9.0 ms, and Saleh saw "up to 5 ms". Both counted the release-to-screen step inside "decode".
• Biggest real delay: Frame pacing. Saleh's Odin was set to Smoothest, which adds ~12 ms. Lowest delay adds ~0.2 ms.
• Not reached: sub-1 ms decode. On this device the codec2 path seems to have a ~2.5–3.5 ms floor even for tiny frames. PXPlay's "< 1 ms" may start its clock later (e.g. after queueInputBuffer returns, which alone is ~0.5 ms here) or use a different measure; we can't see its code.
• Not measured: a high-bitrate moving game. All runs were on the PS5 home screen.

Test notes

• The Odin was driven over adb with Saleh's OK: PS5-423 woken and streamed, then put back in rest via the Quick menu.
• The Odin's MoonCast settings were backed up and restored (checksum identical), and it's back on its launcher.
• test268 (final, 67ce10f) is installed on the Odin.

🤖 Generated with Claude Code