# `SSCMEx.Examples.CameraInference`

Full example: load model, configure camera to model input size, capture one frame,
then run inference.

Run from IEx (from the sscmex or example project):

    SSCMEx.load_nif()

    # run_once returns {:ok, result} or {:error, reason} — handle both
    case SSCMEx.Examples.CameraInference.run_once("/data/yolo11n_detection_cv181x_int8.cvimodel") do
      {:ok, result} -> IO.inspect(result.detections)
      {:error, reason} -> IO.puts("Failed: #{inspect(reason)}")
    end

If you get `{:error, ~c"retrieve_frame_failed"}`: check dmesg. "vpss_get_chn_frame fail" or
"vi err" means the camera/VI pipeline is not delivering frames (sensor or timing). Try
`preset_idx: 3` for a smaller resolution, or a longer warm-up. "ion allocated failed" means
out of ION memory. This example reduces peak usage by configuring the camera output
to the model input resolution before streaming.

# `run_once`

One-shot example: load model, configure camera to model input size, then run inference.

## Options

- `:model_path` (required) - Path to the .cvimodel file
- `:preset_idx` - Sensor preset index (default 3). Output size is still set from model input shape.
- `:camera_fps` - Camera FPS for the RAW channel (default 3)
- `:threshold_score` - Detection score threshold 0.0–1.0 (default 0.5)
- `:threshold_nms` - NMS threshold 0.0–1.0 (default 0.45)
- `:warm_up_ms` - Delay after start_stream before first retrieve (default 1500). Increase if dmesg shows "vi err".

## Returns

- `{:ok, %{frame: image, detections: detections, perf: perf}}` on success
- `{:error, reason}` on failure

## Example

    case SSCMEx.Examples.CameraInference.run_once(
           "/data/yolo11n_detection_cv181x_int8.cvimodel",
           preset_idx: 3,
           threshold_score: 0.5
         ) do
      {:ok, result} ->
        IO.inspect(result.detections)
        IO.inspect(result.perf)
      {:error, reason} ->
        IO.puts("Error: #{inspect(reason)}")
    end

Or use `run_once!/2` to raise on failure (so you get a clear error instead of MatchError):

    result = SSCMEx.Examples.CameraInference.run_once!(path, preset_idx: 3)

# `run_once!`

Same as `run_once/2` but raises on error so you get a clear exception instead of MatchError.

Use when you want to pattern-match only on success; on failure you get e.g.:
`raise SSCMEx.Examples.CameraInference.Error, "retrieve_frame_failed"`

    result = SSCMEx.Examples.CameraInference.run_once!(path, preset_idx: 3)

# `steps`

Step-by-step flow you can copy into your app.

This flow mirrors `sscma-elixir`: load model first, then configure camera output to
model input dimensions before starting the stream.

---

*Consult [api-reference.md](api-reference.md) for complete listing*