microg/GmsCore · error · IOException

Could not find requested camera.

Error message

Could not find requested camera.

What it means

CameraSource.getFacingCameraId() iterates all hardware cameras via Camera.getCameraInfo() looking for one matching the requested facing (front/back) and throws IOException when no camera with that facing exists. This surfaces at camera-open time when the device simply lacks the requested camera.

Source

Thrown at play-services-vision-common/src/main/java/com/google/android/gms/vision/CameraSource.java:354

            });
            camera.addCallbackBuffer(new byte[(int) Math.ceil((double) ((long) (previewSize.getHeight() * previewSize.getWidth() * ImageFormat.getBitsPerPixel(parameters.getPreviewFormat()))) / 8.0D) + 1]);

            return camera;
        } catch (Exception e) {
            camera.release();
            throw e;
        }
    }

    private int getFacingCameraId() throws IOException {
        Camera.CameraInfo info = new Camera.CameraInfo();
        for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
            Camera.getCameraInfo(i, info);
            if (info.facing == facing) {
                return i;
            }
        }
        throw new IOException("Could not find requested camera.");
    }

    private int[] pickFpsRange(Camera camera) throws IOException {
        int requestsFpms = (int) (requestedFps * 1000.0F);
        int[] selectedFpsRange = null;
        int selectedPreviewFpsOffset = Integer.MAX_VALUE;

        for (int[] previewFpsRange : camera.getParameters().getSupportedPreviewFpsRange()) {
            int minOffset = requestsFpms - previewFpsRange[0];
            int maxOffset = requestsFpms - previewFpsRange[1];
            int previewFpsOffset;
            if ((previewFpsOffset = Math.abs(minOffset) + Math.abs(maxOffset)) < selectedPreviewFpsOffset) {
                selectedFpsRange = previewFpsRange;
                selectedPreviewFpsOffset = previewFpsOffset;
            }
        }
        if (selectedFpsRange == null) throw new IOException("Could not find suitable preview frames per second range.");
        return selectedFpsRange;

View on GitHub (pinned to 157c9d86ac)

Solutions

  1. Detect available facings first by iterating Camera.getNumberOfCameras()/getCameraInfo and pick a supported one
  2. Default to CAMERA_FACING_BACK if front is unavailable (or vice versa)
  3. Show a user-facing message when the device lacks the requested camera
  4. Guard start() in try/catch for IOException and fall back to the other facing

Example fix

// before
CameraSource source = new CameraSource.Builder(context, detector)
    .setFacing(CameraSource.CAMERA_FACING_FRONT)
    .build();
source.start(); // IOException on devices without a front camera
// after
int facing = hasCamera(CameraInfo.CAMERA_FACING_FRONT)
    ? CameraSource.CAMERA_FACING_FRONT : CameraSource.CAMERA_FACING_BACK;
try {
    CameraSource source = new CameraSource.Builder(context, detector)
        .setFacing(facing).build();
    source.start();
} catch (IOException e) {
    // no suitable camera on this device
}
Defensive patterns

Strategy: try-catch

Validate before calling

boolean hasFacing(int facing) {
    Camera.CameraInfo info = new Camera.CameraInfo();
    for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
        Camera.getCameraInfo(i, info);
        if (info.facing == facing) return true;
    }
    return false;
}

Type guard

null

Try / catch

try {
    cameraSource.start();
} catch (IOException e) {
    // no camera with the requested facing: fall back or inform the user
}

Prevention

When it happens

Trigger: Requesting CameraSource with CameraInfo.CAMERA_FACING_FRONT (or back) on a device that has no front (or back) camera; calling start() on devices with a single rear camera when front was requested.

Common situations: Desktop/emulator or IoT devices without the requested camera; enterprise tablets with rear-only cameras; hardcoded FRONT camera assumption in code running on rear-only hardware.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of microg/GmsCore@157c9d86ac (2026-09-06). Data as JSON: /api/errors/56f1478a457b53f5. Report an issue: GitHub.