# signal:// ASCII

> Convert images and video into ASCII / ANSI art. The browser studio streams
> video and webcam in real time; the HTTP API renders single images for agents
> and automations. Version 0.1.1.

## What it does
- Live video-to-ASCII studio (runs entirely client-side in the browser).
- Trusted A2V handoff: open https://a2v.platphormnews.com and stream latest ASCII frames from video or webcam with fixed-origin window.postMessage.
- Server API to convert uploaded/base64 images or trusted HTTPS image URLs to text, ANSI (24-bit color), HTML, JSON, or SVG.
- MCP server so agents can render ASCII as a tool call.
- Public-safe W3C render and MCP lifecycles in Trace when server-side platform auth is configured; image bytes remain redacted.
- Source-aware Auto Director with bounded quality-rubric rounds and honest target_met/best_effort evidence.
- Adaptive rate-distortion glyph codebooks with measured RMSE, plus compact rgb24-b64-v1 chroma for deASCII/A2V handoffs.

## Math under the hood
- Linear-light perceptual luminance (sRGB -> linear -> Rec.709 -> re-encode).
- High-quality pyramid downscaling for clean, alias-free source sampling.
- Unsharp-mask detail enhancement that restores fine texture lost when the
  frame is shrunk to the character grid.
- Floyd-Steinberg error-diffusion dithering for gradient fidelity.
- Adaptive recursive Bayesian temporal filter (Kalman-style gain) that denoises
  static regions while staying crisp on motion — the key to a stable stream.

## Endpoints
- GET  https://v2a.platphormnews.com/api/health — liveness + capabilities
- POST https://v2a.platphormnews.com/api/v1/render — image -> ascii (multipart image, or JSON { imageUrl | imageBase64 })
- GET  https://v2a.platphormnews.com/api/v1/a2v-handoff — public-safe V2A -> A2V handoff protocol
- POST https://v2a.platphormnews.com/api/mcp — Model Context Protocol (JSON-RPC 2.0), tool: render_ascii
- GET  https://v2a.platphormnews.com/api/openapi.json — OpenAPI 3.1 spec
- GET  https://v2a.platphormnews.com/api/docs — platform route and limitation reference
- GET  https://v2a.platphormnews.com/api/v1/interoperability — ASCII/deASCII/V2A/A2V roles, APIs, MCP endpoints, and handoff boundaries

## Render parameters
- columns (integer 8–400, default 120): Output width in characters.
- charset (enum, default detailed): One of: standard, detailed, blocks, binary, dots, minimal.
- format (enum, default text): text | ansi | html | json | json-compact | svg.
- color (boolean, default false): Per-cell 24-bit color (ignored by plain text).
- invert (boolean, default false): Invert luminance mapping.
- contrast (float 0.2–4, default 1.15): Tonal contrast multiplier.
- brightness (float -150–150, default 0): Luminance offset.
- saturation (float 0–4, default 1.4): Color-mode saturation boost.
- gamma (float 0.2–3, default 1): Perceptual midtone response.
- edges (boolean, default false): Sobel edge-detection line-art mode.
- edgeStrength (float 0.1–5, default 1.8): Edge magnitude multiplier.
- dither (boolean, default false): Floyd–Steinberg error diffusion.
- sharpen (float 0–1, default 0.35): Unsharp-mask detail enhancement.
- autoLevels (float 0–1, default 0.9): Automatic percentile histogram stretch.
- structure (float 0–1, default 0.55): Contour-aware directional glyph substitution ( - / | \ ).
- denoise (float 0–1, default 0.35): Edge-preserving bilateral denoising before detail recovery.
- motionSensitivity (float 0–1, default 0.7): Motion responsiveness in the final Bayesian posterior update.
- autoOptimize (float 0–1, default 0.9): Strength of source-aware Auto Director tuning against the selected quality rubric.
- qualityTarget (enum, default balanced): balanced | portrait | motion | low-light | round-trip.
- glyphStrategy (enum, default adaptive): adaptive chooses the smallest glyph codebook under maxGlyphRmse; fixed preserves the selected ramp.
- maxGlyphRmse (float 0.005–0.1, default 0.03): Maximum normalized luminance quantization RMSE for adaptive glyph selection.
- monoColor (hex, default #e5e5e5): Color for mono/ansi/svg/html output.

## Quick start
curl -F "image=@photo.jpg" "https://v2a.platphormnews.com/api/v1/render?columns=120&format=ansi&color=true"

Remote imageUrl hosts are restricted to asciicast.stream, *.platphormnews.com,
and explicit V2A_IMAGE_FETCH_ALLOWLIST entries. Redirects, DNS results,
content type, response size, and time are bounded.

## A2V handoff
- Target: https://a2v.platphormnews.com
- Protocol: platphorm.v2a.a2v.handoff.v1
- Webcam launch: https://a2v.platphormnews.com/?handoff=v2a&protocol=platphorm.v2a.a2v.handoff.v1&mode=webcam-stream&source=v2a.platphormnews.com&traceId=TRACE_ID
- Backend async checks use PLATPHORM_API_KEY when configured.
- REST and MCP responses expose the accepted or generated trace ID and Trace URL; measured output evidence is linked to the producing render span.
- Boundary: webcam/video media stays local; only ASCII text frames and render metadata are posted to the trusted A2V origin.
- Chroma: exact optional rgb24-b64-v1 per-cell RGB; connection status requires platphorm:a2v:ack.

## deASCII handoff
- Fixed target: https://deascii.platphormnews.com
- Small frames use an inline base64url JSON fragment; every frame also uses trusted postMessage.
- Payload: platphorm-v2a-handoff.v2 with line-preserving ASCII, optional rgb24-b64-v1 colorGrid, and processing evidence.
- Connection status requires platphorm.deascii.acceptedAsciiPayload.

curl -X POST https://v2a.platphormnews.com/api/v1/render \
  -H "Content-Type: application/json" \
  -d '{"imageUrl":"https://asciicast.stream/test-portrait.png","columns":160,"format":"html","color":true}'

## MCP
POST https://v2a.platphormnews.com/api/mcp with a JSON-RPC body:
{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"render_ascii","arguments":{"imageUrl":"https://asciicast.stream/test-portrait.png","columns":100,"color":true}}}