iOS: Add new RTCVideoSource interface

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

+/*
+ *  Copyright (c) 2017 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 "webrtc/sdk/objc/Framework/Classes/objcvideotracksource.h"
+
+#import "RTCVideoFrame+Private.h"
+
+#include "webrtc/common_video/include/corevideo_frame_buffer.h"
+
+namespace webrtc {
+
+ObjcVideoTrackSource::ObjcVideoTrackSource() {}
+
+void ObjcVideoTrackSource::OnOutputFormatRequest(int width,
+                                                 int height,
+                                                 int fps) {
+  cricket::VideoFormat format(width, height,
+                              cricket::VideoFormat::FpsToInterval(fps), 0);
+  video_adapter()->OnOutputFormatRequest(format);
+}
+
+void ObjcVideoTrackSource::OnCapturedFrame(RTCVideoFrame* frame) {
+  const int64_t timestamp_us = frame.timeStampNs / rtc::kNumNanosecsPerMicrosec;
+  const int64_t translated_timestamp_us =
+      timestamp_aligner_.TranslateTimestamp(timestamp_us, rtc::TimeMicros());
+
+  int adapted_width;
+  int adapted_height;
+  int crop_width;
+  int crop_height;
+  int crop_x;
+  int crop_y;
+  if (!AdaptFrame(frame.width, frame.height,
+                  timestamp_us,
+                  &adapted_width, &adapted_height,
+                  &crop_width, &crop_height,
+                  &crop_x, &crop_y)) {
+    return;
+  }
+
+  rtc::scoped_refptr<VideoFrameBuffer> buffer;
+  if (adapted_width == frame.width && adapted_height == frame.height) {
+    // No adaption - optimized path.
+    buffer = frame.videoBuffer;
+  } else if (frame.nativeHandle) {
+    // Adapted CVPixelBuffer frame.
+    buffer = new rtc::RefCountedObject<CoreVideoFrameBuffer>(
+        static_cast<CVPixelBufferRef>(frame.nativeHandle),
+        adapted_width, adapted_height,
+        crop_width, crop_height,
+        crop_x, crop_y);
+  } else {
+    // Adapted I420 frame.
+    // TODO(magjed): Optimize this I420 path.
+    rtc::scoped_refptr<I420Buffer> i420_buffer =
+        I420Buffer::Create(adapted_width, adapted_height);
+    i420_buffer->CropAndScaleFrom(*frame.videoBuffer,
+                                  crop_x, crop_y,
+                                  crop_width, crop_height);
+    buffer = i420_buffer;
+  }
+
+  // Applying rotation is only supported for legacy reasons and performance is
+  // not critical here.
+  webrtc::VideoRotation rotation =
+      static_cast<webrtc::VideoRotation>(frame.rotation);
+  if (apply_rotation() && rotation != kVideoRotation_0) {
+    buffer = I420Buffer::Rotate(buffer->NativeToI420Buffer(), rotation);
+    rotation = kVideoRotation_0;
+  }
+
+  OnFrame(webrtc::VideoFrame(buffer, rotation, translated_timestamp_us));
+}
+
+}  // namespace webrtc