Add support for more resolutions on iOS/macOS

webrtc/sdk/objc/Framework/Classes/avfoundationvideocapturer.mm

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "avfoundationvideocapturer.h"
 
 #import <AVFoundation/AVFoundation.h>
 #import <Foundation/Foundation.h>
 #if TARGET_OS_IPHONE
 #import <UIKit/UIKit.h>
 #endif
 
 #import "RTCDispatcher+Private.h"
 #import "WebRTC/RTCLogging.h"
 #if TARGET_OS_IPHONE
 #import "WebRTC/UIDevice+RTCDevice.h"
 #endif
 
 #include "webrtc/base/bind.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/thread.h"
 #include "webrtc/common_video/include/corevideo_frame_buffer.h"
 
-// TODO(tkchin): support other formats.
-static NSString *const kDefaultPreset = AVCaptureSessionPreset640x480;
-static NSString *const kIPhone4SPreset = AVCaptureSessionPreset352x288;
-static cricket::VideoFormat const kDefaultFormat =
-    cricket::VideoFormat(640,
-                         480,
-                         cricket::VideoFormat::FpsToInterval(30),
-                         cricket::FOURCC_NV12);
-// iPhone4S is too slow to handle 30fps.
-static cricket::VideoFormat const kIPhone4SFormat =
-    cricket::VideoFormat(352,
-                         288,
-                         cricket::VideoFormat::FpsToInterval(15),
-                         cricket::FOURCC_NV12);
+struct AVCaptureSessionPresetResolution {
+  NSString *sessionPreset;
+  int width;
+  int height;
+  cricket::VideoFormat getVideoFormat(int framerate) const {

[magjed_webrtc, 2016/08/15 10:10:23]

Structs are not allowed to have methods providing behavior.
https://google.github.io/styleguide/cppguide.html#Structs_vs._Classes

I suggest you just inline this function and use preset.width/preset.height
directly.

+    return cricket::VideoFormat(height, width,
+                                cricket::VideoFormat::FpsToInterval(framerate),
+                                cricket::FOURCC_NV12);
+  }
+};
+
+#if TARGET_OS_IPHONE
+static const AVCaptureSessionPresetResolution kAvailablePresets[] = {
+  { AVCaptureSessionPreset352x288, 352, 288},
+  { AVCaptureSessionPreset640x480, 640, 480},
+  { AVCaptureSessionPreset1280x720, 1280, 720},
+  { AVCaptureSessionPreset1920x1080, 1920, 1080},
+};
+#else // macOS
+static const AVCaptureSessionPresetResolution kAvailablePresets[] = {
+  { AVCaptureSessionPreset320x240, 320, 240},
+  { AVCaptureSessionPreset352x288, 352, 288},
+  { AVCaptureSessionPreset640x480, 640, 480},
+  { AVCaptureSessionPreset960x540, 960, 540},
+  { AVCaptureSessionPreset1280x720, 1280, 720},
+};
+#endif
+
+// mapping from cricket::VideoFormat to AVCaptureSession presets

[magjed_webrtc, 2016/08/15 10:10:23]

Super-nit: comments should have proper capitalization and punctuation.
https://google.github.io/styleguide/cppguide.html#Punctuation,_Spelling_and_G...

This applies to your other comments as well.

+static NSString *GetSessionPresetForVideoFormat(
+  const cricket::VideoFormat& format) {
+  for (const auto preset : kAvailablePresets) {
+    // Check both orientations
+    if ((format.width == preset.width && format.height == preset.height) ||
+        (format.width == preset.height && format.height == preset.width)) {
+      return preset.sessionPreset;
+    }
+  }
+  // Nothing found, use default
+  return AVCaptureSessionPreset640x480;
+}
 
 // This class used to capture frames using AVFoundation APIs on iOS. It is meant
 // to be owned by an instance of AVFoundationVideoCapturer. The reason for this
 // because other webrtc objects own cricket::VideoCapturer, which is not
 // ref counted. To prevent bad behavior we do not expose this class directly.
 @interface RTCAVFoundationVideoCapturerInternal : NSObject
     <AVCaptureVideoDataOutputSampleBufferDelegate>
 
 @property(nonatomic, readonly) AVCaptureSession *captureSession;
 @property(nonatomic, readonly) dispatch_queue_t frameQueue;
@@ skipping 300 matching lines @@
 #pragma mark - Private
 
 - (BOOL)setupCaptureSession {
   AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
 #if defined(__IPHONE_7_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_7_0
   NSString *version = [[UIDevice currentDevice] systemVersion];
   if ([version integerValue] >= 7) {
     captureSession.usesApplicationAudioSession = NO;
   }
 #endif
-  NSString *preset = kDefaultPreset;
-#if TARGET_OS_IPHONE
-  if ([UIDevice deviceType] == RTCDeviceTypeIPhone4S) {
-    preset = kIPhone4SPreset;
-  }
-#endif
-  if (![captureSession canSetSessionPreset:preset]) {
-    RTCLogError(@"Session preset unsupported.");
-    return NO;
-  }
-  captureSession.sessionPreset = preset;

[kthelgason, 2016/08/15 08:43:37]

I don't see why we set the sessionPreset here, and again in `Start`. 
I tried removing this and everything _seems_ to work. Please let me know if/why
this should be here.

[magjed_webrtc, 2016/08/15 10:10:23]

sessionPreset used to be set only from here, so you have simply moved it to
'Start'. I think that is fine.

 
   // Add the output.
   AVCaptureVideoDataOutput *videoDataOutput = [self videoDataOutput];
   if (![captureSession canAddOutput:videoDataOutput]) {
     RTCLogError(@"Video data output unsupported.");
     return NO;
   }
   [captureSession addOutput:videoDataOutput];
 
   // Get the front and back cameras. If there isn't a front camera
@@ skipping 185 matching lines @@
 
 struct AVFoundationFrame {
   AVFoundationFrame(CVImageBufferRef buffer, int64_t time)
     : image_buffer(buffer), capture_time(time) {}
   CVImageBufferRef image_buffer;
   int64_t capture_time;
 };
 
 AVFoundationVideoCapturer::AVFoundationVideoCapturer()
     : _capturer(nil), _startThread(nullptr) {
-  // Set our supported formats. This matches preset.
+  // Set our supported formats. This matches kAvailablePresets
+  _capturer =
+    [[RTCAVFoundationVideoCapturerInternal alloc] initWithCapturer:this];
+
   std::vector<cricket::VideoFormat> supported_formats;
+  int framerate = 30;
+
 #if TARGET_OS_IPHONE
   if ([UIDevice deviceType] == RTCDeviceTypeIPhone4S) {
-    supported_formats.push_back(cricket::VideoFormat(kIPhone4SFormat));
     set_enable_video_adapter(false);
-  } else {
-    supported_formats.push_back(cricket::VideoFormat(kDefaultFormat));
+    framerate = 15;
   }
-#else
-  supported_formats.push_back(cricket::VideoFormat(kDefaultFormat));
 #endif
+
+  for (const auto preset : kAvailablePresets) {
+    if ([_capturer.captureSession canSetSessionPreset:preset.sessionPreset]) {
+      supported_formats.push_back(preset.getVideoFormat(framerate));
+    }
+  }
+
   SetSupportedFormats(supported_formats);
-  _capturer =
-      [[RTCAVFoundationVideoCapturerInternal alloc] initWithCapturer:this];
 }
 
 AVFoundationVideoCapturer::~AVFoundationVideoCapturer() {
   _capturer = nil;
 }
 
 cricket::CaptureState AVFoundationVideoCapturer::Start(
     const cricket::VideoFormat& format) {
   if (!_capturer) {
     LOG(LS_ERROR) << "Failed to create AVFoundation capturer.";
     return cricket::CaptureState::CS_FAILED;
   }
   if (_capturer.isRunning) {
     LOG(LS_ERROR) << "The capturer is already running.";
     return cricket::CaptureState::CS_FAILED;
   }
-  if (format != kDefaultFormat && format != kIPhone4SFormat) {
-    LOG(LS_ERROR) << "Unsupported format provided.";
+
+  NSString *desiredPreset = GetSessionPresetForVideoFormat(format);
+
+  [_capturer.captureSession beginConfiguration];
+  if (![_capturer.captureSession canSetSessionPreset:desiredPreset]) {
+    LOG(LS_ERROR) << "Unsupported video format.";
     return cricket::CaptureState::CS_FAILED;
   }
+  _capturer.captureSession.sessionPreset = desiredPreset;
+  [_capturer.captureSession commitConfiguration];
 
   // Keep track of which thread capture started on. This is the thread that
   // frames need to be sent to.
   RTC_DCHECK(!_startThread);
   _startThread = rtc::Thread::Current();
 
   SetCaptureFormat(&format);
   // This isn't super accurate because it takes a while for the AVCaptureSession
   // to spin up, and this call returns async.
   // TODO(tkchin): make this better.
@@ skipping 101 matching lines @@
   }
 
   OnFrame(cricket::WebRtcVideoFrame(buffer, webrtc::kVideoRotation_0,
                                     translated_camera_time_us, 0),
           captured_width, captured_height);
 
   CVBufferRelease(image_buffer);
 }
 
 }  // namespace webrtc