luke/esp32-poe-scrypted-viewport/main/http_api.c, branch v1.3.0

firmware: split stream recv into its own task with 3-buffer ping-pong

2026-06-21T01:50:43+00:00

handle_client previously ran recv → decode → paint serially on one FreeRTOS task. The kernel TCP buffer filled during decode+paint (~6ms), and against the IDF-default 5760-byte window the sender naturally stop-go-rate-limited to ~consumption. Raising the window to 65535 (previous experiment) regressed g2g from ~100ms to 17s growing unbounded — the sender pumped 45+ segments per round into a kernel buffer the app couldn't drain in time, and there was no way to skip-oldest on the kernel queue. This commit decouples recv from decode+paint: recv-task: owns the socket. Reads header + body into one of three preallocated PSRAM body buffers. On body complete, swaps the just-filled buffer into a 1-deep pending slot and picks a free buffer for the next recv. If the slot already held a frame (decode is slow), drops oldest in place — mirror of the Scrypted-side skip-oldest from e5acf93. decode-task: waits on a binary semaphore. On signal, claims pending, then decodes + paints without holding any shared lock. Frees its prior buffer implicitly by overwriting s_decode_idx on the next claim. 3 PSRAM body buffers (~3MB of 28MB free) ensure the invariant {recv_idx, pending_idx, decode_idx} are pairwise distinct without ever blocking recv. jpeg_decoder.c grew an alloc_input_buffer helper + jpeg_decoder_decode now takes an explicit input pointer so the stream and http_api snapshot paths don't share scratch. New stats: - recv_dropped_oldest: per-window count of pending-slot overwrites - decode_idle_min/avg/max_us: time decode-task spent waiting on signal Measurement at IDF-default 5760 window, Unifi medium substream: before split: recv_avg=32ms recv_max~44ms fps=22-26 (recv blocked during 6ms decode+paint; chunk_max capped at 5760) after split: recv_avg=17ms recv_max=18-37ms fps=21-29 steady, decode_idle_avg=27-40ms (decode mostly waiting), drop_oldest=0, painted at source rate The bottleneck moved from 'decode+paint serializes recv' to the wire's own send rate. Bigger windows are now safe (recv-task drains continuously, can't bury us), but won't add fps until source rate goes up — that's a separate conversation.

firmware: recv-throughput instrumentation (FIONREAD pre-body, recv() call/chunk stats, SO_RCVBUF probe)

2026-06-21T01:16:01+00:00

Per-frame samples aggregated over the existing 30-frame window: - queued_at_body_start (FIONREAD just before body recv loop): how much of the frame the kernel already absorbed during the previous decode+paint. Close to jpeg_len → wire delivered the full frame while we were busy (we're decode/paint-bound). Much smaller → wire is throttled (window or buffer too small to absorb a frame in our paint window). - recv_calls: number of recv() syscalls the body read needed per frame. High → small chunks → window-throttled sender. - recv_chunk min/avg/max: bytes returned per recv() return in the window. Avg = window body bytes / total syscalls. - SO_RCVBUF: one-shot getsockopt at accept, logged and stashed in stats. Confirms whether sdkconfig values reached the build — TCP_WND_DEFAULT discrepancies are otherwise invisible. All surfaced in the windowed log and in /state JSON alongside the existing recv/dec/paint/idle stats. No behavior change yet.

firmware: OTA firmware updates via POST /firmware + rollback

2026-06-20T18:03:23+00:00

Streams the raw .bin to the inactive ota_0/ota_1 slot via esp_ota_*, flips otadata, replies 200, reboots after 500 ms. Single-shot guarded by atomic_flag (409 on concurrent). CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE armed: new images boot pending-verify and ota_arm_healthy_timer marks them valid after 30 s of healthy uptime; otherwise the bootloader reverts on next reset. /state gains ota_state.

phase 4: glass-to-glass via 16-byte stream header + /state stream stats

2026-06-20T16:38:14+00:00

Wire format change: stream frames now carry a 4-byte "VPRT" magic + 4-byte jpeg_len + 4-byte seq + 4-byte event_us_low. Total 16 bytes (was 8). The firmware sniffs the first 4 bytes per frame: if they spell VPRT it reads the remaining 12 bytes of v1 header; otherwise it interprets bytes 0-3 as jpeg_len for the old v0 8-byte format and reads 4 more for seq. Lets a v1 firmware accept a v0 (legacy) Scrypted script during the rollout window. v0 will be removed once all field deployments roll forward. event_us_low is the low 32 bits of the Scrypted host's monotonic µs at camera-event arrival. The firmware does NOT interpret it (the clocks aren't sync'd); it just stamps it on every painted frame and exposes the most recent value via /state. The script polls /state every 5s during an active stream, reads last_paint_event_us_low, and computes glass-to-glass = (now_us_low - last_paint_event_us_low) with 32-bit wrap. 30s sanity ceiling on the wrap to discard event timestamps from before the stream started. Also expose the firmware's just-closed 30-frame window stats via /state under the "stream" key — frames, bytes, window_us, plus min/avg/max for recv/dec/paint/idle. Lets external tools (a curl loop, the Scrypted plugin, etc) poll the firmware's view without parsing serial logs. Firmware: - stream_server.h: 16-byte v1 wire spec, stream_server_stats_t struct, stream_server_snapshot_stats(out) getter. - stream_server.c: magic-detect header read path, last_event_us_low capture into per-connection state, portMUX-protected window-stats snapshot at every 30-frame roll. - http_api.c: GET /state JSON gains a "stream" sub-object with the full snapshot. - viewport_state.h: VIEWPORT_VERSION 1.0.0 → 1.1.0 (new /state shape). Scrypted: - startStream captures eventUsLow = (tEvent * 1000) >>> 0. - TCP demux loop writes the 16-byte v1 header with the VPRT magic. - New fwPoller setInterval (5s) fetches /state, parses .stream, computes g2g, emits one summary line per poll cycle.

cleanup phase 2: delete HTTP-streaming-era dead code

2026-06-20T16:23:23+00:00

Both sides simultaneously because the script's X-Frame-Seq sender and the firmware's X-Frame-Seq receiver negotiated a contract that's now retired entirely. Firmware (main/http_api.c): - Delete static uint32_t s_last_painted_seq (declaration + reset in state_post_handler + the read in frame_post_handler + the assignment after paint). - Delete the X-Frame-Seq header read (httpd_req_get_hdr_value_str + strtoul block). - Delete the X-Frame-Drop: stale-seq response path. - Delete the entire Server-Timing httpd_resp_set_hdr block. - Delete the setsockopt(TCP_NODELAY) at frame_post_handler entry. /frame is a single body POST → empty 204; no second packet for Nagle to coalesce with on the response side. - Delete static int64_t s_last_post_us + the idle_us computation. /frame fires at most once per wake; idle gap between wakes is dominated by user/event timing, not anything firmware-controllable. - Drop the per-10-frames condition on the timing log — /frame fires rarely enough that one log per snapshot is the right cadence — and rename "frame N: ..." → "snapshot: ..." to match. - Drop cfg.max_open_sockets 4 → 2 (snapshot POST + concurrent /state or /config). - Drop #include "lwip/sockets.h" (orphaned with TCP_NODELAY). Script (scrypted/scrypted-viewport.ts): - Delete the agents Map + agentFor() method (per-host keepAlive Agent pool; over-engineered for ~1 POST/min control plane). - Delete httpRequest() helper (40 lines wrapping http.request to surface tHeaders/tDone — no consumer reads those fields anymore). - Rewrite postJSON() to a 10-line fetch() with AbortSignal.timeout. - Delete the frameSeq Map + the seq counter + X-Frame-Seq header on the snapshot fetch + the X-Frame-Drop response check + the frameSeq.delete in stopStream. - Extract buildVf(orientation, panelW, panelH) helper near top of ScryptedViewportProvider — used by both startStream (live) and pushSnapshot (one-shot ffmpeg fallback). TCP_NODELAY references remain in the live-stream socket path (scrypted-viewport.ts:773, 788). That's a different socket (raw net.Socket on TCP/81) and noDelay there is what eliminates Nagle stalls under the streaming-heavy live workload. Load-bearing.

cleanup phase 1: stale-comment refresh, zero behavior change

2026-06-20T16:16:52+00:00

Removes/rewrites every comment that referenced the dead HTTP-streaming architecture so a reader of v1.0.0+ source isn't chasing a model that's been gone for several releases. No code paths changed; this is the safe pre-pass before Phase 2's actual deletions. Firmware (main/http_api.c): - s_last_painted_seq / s_last_post_us / X-Frame-Seq parse / stale- frame guard / Server-Timing emission / TCP_NODELAY setsockopt / max_open_sockets=4 — each block now leads with "(Legacy from the HTTP-streaming era; removed in Phase 2)" so the reader knows the block is doomed, not load-bearing. - /frame dim-mismatch comment narrowed: panel-native is always 800x480 BGR888, no Scrypted-side variation expected; Scrypted does the rotation+scale via sharp/mediaManager/ffmpeg cascade (snapshot) or ffmpeg -vf (stream). - "Single in-flight frame. Concurrent posts get 503" rewritten to reflect: decoder mutex now mostly serves to fence /frame snapshots against an active stream_server decode. Firmware (main/stream_server.c:136-142): - FIONREAD-skip rationale reduced from a 7-line paragraph to one sentence; the savings/tradeoff math now lives in the plan, not the per-line comment. Script (scrypted/scrypted-viewport.ts): - Top-of-file tuning constants block drops the "frame_interval_ms removed", "fps filter", "in-flight back-to-back startStream" rationale; one short line covers the model: "Stream rate is paced by camera + TCP backpressure; no app-level fps cap." - agentFor() rationale rewritten: this Agent is over-engineered for control-plane traffic (~1 POST/min steady state) — a legacy of when it backed per-frame /frame POSTs. Marked for Phase 2 retirement. - noDelay on Agent: clarified it's now a no-op safety for control plane (was load-bearing for live-stream pipelining). - snapshot fire-and-forget comment: replaced X-Frame-Seq-race rationale with the actual TCP-streaming truth (sharp/mediaManager/ ffmpeg cascade race against stream socket bring-up). - writeLatencies probe: rewrote the "keep-alive socket" comment (live stream uses raw net.Socket, not the http.Agent pool). - socketBackpressured: explicit "diagnostic only, never gates writes" comment added at declaration site. - skipLogger header: rewrote the inFlight/MAX_INFLIGHT/fps-filter rationale into a one-line description of what the log line actually emits today. - frameSeq map: now flagged as legacy of HTTP-streaming era, retired in Phase 2.

firmware: build fixes — esp_app_format component + forward-declare s_last_painted_seq

2026-06-20T00:31:23+00:00

Two build breaks discovered when actually compiling the prior commits: - main/CMakeLists.txt missing esp_app_format requirement, so esp_app_desc.h couldn't be resolved when app_main.c included it for the boot-time git-hash log. - s_last_painted_seq is referenced inside state_post_handler (reset to 0 on /state wake) but the static was declared further down the file alongside the other /frame state. C requires declaration before use — forward declare it above state_post_handler and keep a stub comment at the original location.

disable Nagle on /frame socket + add min/max/worst-frame to script log

2026-06-20T00:15:28+00:00

#1: TCP_NODELAY for /frame ESP-IDF lwIP defaults Nagle ON. /frame is the worst Nagle workload: ~140KB body POST followed by an empty 204 response, no follow-up data either way. Both the final partial-MTU body packet and the response packet can sit in the kernel send buffer up to 40ms waiting for an ACK that the other side is delaying-ACKing — silently adding tens of ms to every frame's wall time and showing up as a fat net_up bucket on the Scrypted side. setsockopt(TCP_NODELAY) at handler entry on every /frame. Cheap and idempotent. Includes the /state and /config sockets too — those are infrequent but small responses also benefit. #2: min/max + worst-frame decomposition in the Scrypted log The p50/p95 line answered "what's typical" but not "what happened in the worst frame this window". Now every 10-fetch log adds: - min and max columns alongside p50/p95 per bucket - a worst-frame breakdown row: identifies the single slowest fetch in the window and decomposes its wall time across all stages. Answers "did the slow frame get gated by emit→post (ffmpeg backed up), net_up (TCP/handshake spike), or fw_dec (large JPEG)?" directly, instead of us inferring from percentiles. Together these are the prerequisites for evaluating whether further optimization (HTTP keep-alive, chunked streaming) is worth pursuing.

unified end-to-end per-frame instrumentation + version stamps

2026-06-20T00:07:55+00:00

Cross-side timing was opaque: script saw "req=70ms" but couldn't split TCP/dispatch overhead from firmware decode time, and firmware serial logs and Scrypted console logs couldn't be correlated. Firmware /frame handler now emits Server-Timing on every response with per-stage breakdown: Server-Timing: recv;dur=X, dec;dur=Y, paint;dur=Z, post;dur=W, handle;dur=total Script parses it, joins by X-Frame-Seq implicitly (one POST per seq), derives net_up = req − fw_total, and logs a multi-line p50/p95 breakdown every 10 fetches: fetch "kitchen" #10 (jpeg=137KB) wall p50=65ms p95=140ms emit→post p50=0ms p95=2ms (queue wait) req p50=62ms p95=135ms (fetch → Response headers) net_up p50=43ms p95=110ms (TCP + body wire + dispatch) fw_recv p50=12ms p95=18ms (body off the wire) fw_dec p50=6ms p95=8ms (hardware JPEG) fw_paint p50=0.1ms p95=0.2ms (backbuffer flip) fw_post p50=0.4ms p95=0.6ms body-read p50=1ms (drain — empty body) inflight d0=8 d1=2 d2=0 stale-drops=0 Plus version stamps on both sides for the "is the user on the right code" question: - CMakeLists: PROJECT_VER = git short hash + -dirty marker if dirty. esp_app_get_description()->version exposes it at runtime. Boot log: "Scrypted Viewport boot (v0.1.0 build=4cf36e2-dirty)". - TS: SCRIPT_VERSION const at the top, bumped per commit, logged at script-eval: "Scrypted Viewport up (script=4cf36e2). Callback ..."

add X-Frame-Seq monotonic ordering for pipelined /frame POSTs

2026-06-15T14:32:57+00:00

With two /frame POSTs in flight on separate sockets, the firmware's JPEG decoder mutex serialises decode but FreeRTOS semaphore acquisition is not FIFO — under jitter the later-arriving older frame can grab the lock first and paint over the newer one, producing brief "panel travels backward in time" glitches. Scrypted side: - Per-viewport monotonic frameSeq counter, sent as X-Frame-Seq on every /frame POST. Reset on stopStream so each new stream starts at 1. Firmware side: - s_last_painted_seq tracks the highest seq we've painted. Frame arrives, mutex acquired, body received — if seq <= s_last_painted_seq the frame is dropped (200 OK + X-Frame-Drop: stale-seq header) and the mutex released without touching the back buffer. - s_last_painted_seq resets to 0 on POST /state {wake} so the next stream's seq=1 isn't rejected because the previous session reached a higher counter. - Missing/zero X-Frame-Seq (legacy clients) skips the check entirely — preserves pre-pipelining behaviour.