feat: Add pixelFormat field (#559)

* Add `mediaSubType` field to device formats

* Create FourCharCode `toString` extension

* Move pixelFormat -> `AVCaptureDevice.Format+toDictionary`

* `mediaSubType` -> `pixelFormat` + non-optional

* ts pixelFormat `string` -> specific formats

* Add default pixelFormat value of `420v` on Android

Co-authored-by: tcoldwell72 <31568400+tcoldwell72@users.noreply.github.com>

android/src/main/java/com/mrousavy/camera/CameraViewModule.kt

@@ -244,6 +244,9 @@ class CameraViewModule(reactContext: ReactApplicationContext) : ReactContextBase
                 }
               }
 
+              // TODO: Get the pixel format programatically rather than assuming a default of 420v
+              val pixelFormat = "420v"
+
               val format = Arguments.createMap()
               format.putDouble("photoHeight", size.height.toDouble())
               format.putDouble("photoWidth", size.width.toDouble())
@@ -260,6 +263,7 @@ class CameraViewModule(reactContext: ReactApplicationContext) : ReactContextBase
               format.putArray("frameRateRanges", frameRateRanges)
               format.putString("autoFocusSystem", "none") // TODO: Revisit getAvailableCameraDevices (autoFocusSystem) (CameraCharacteristics.CONTROL_AF_AVAILABLE_MODES or CameraCharacteristics.LENS_INFO_FOCUS_DISTANCE_CALIBRATION)
               format.putArray("videoStabilizationModes", videoStabilizationModes)
+              format.putString("pixelFormat", pixelFormat)
               formats.pushMap(format)
             }
           }

ios/Extensions/AVCaptureDevice.Format+toDictionary.swift

@@ -42,6 +42,7 @@ extension AVCaptureDevice.Format {
           "maxFrameRate": $0.maxFrameRate,
         ]
       },
+      "pixelFormat": CMFormatDescriptionGetMediaSubType(formatDescription).toString()
     ]
 
     if #available(iOS 13.0, *) {

ios/Extensions/FourCharCode+toString.swift

@@ -0,0 +1,17 @@
+//
+//  FourCharCode+toString.swift
+//  VisionCamera
+//
+//  Created by Thomas Coldwell on 28/10/2021.
+//  Based off this SO answer: https://stackoverflow.com/a/25625744
+//
+
+extension FourCharCode {
+    func toString() -> String {
+        var s: String = String (UnicodeScalar((self >> 24) & 255)!)
+        s.append(String(UnicodeScalar((self >> 16) & 255)!))
+        s.append(String(UnicodeScalar((self >> 8) & 255)!))
+        s.append(String(UnicodeScalar(self & 255)!))
+        return (s)
+    }
+}

src/CameraDevice.ts

@@ -1,4 +1,5 @@
 import type { CameraPosition } from './CameraPosition';
+import type { PixelFormat } from './PixelFormat';
 
 /**
  * Indentifiers for a physical camera (one that actually exists on the back/front of the device)
@@ -171,6 +172,10 @@ export interface CameraDeviceFormat {
    * All supported video stabilization modes
    */
   videoStabilizationModes: VideoStabilizationMode[];
+  /**
+   * Specifies the pixel format on iOS. e.g. 420v, 420f
+   */
+  pixelFormat: PixelFormat;
 }
 
 /**

src/PixelFormat.ts

@@ -0,0 +1,7 @@
+/**
+ * Represents the pixel format of a `Frame`.
+ * * `420v`: 420 YpCbCr 8 Bi-Planar Video Range
+ * * `420f`: 420 YpCbCr 8 Bi-Planar Full Range
+ * * `x420`: 420 YpCbCr 10 Bi-Planar Video Range
+ */
+export type PixelFormat = '420f' | '420v' | 'x420';