New method CreateScaledFrame in the VideoFrameFactory interface.

webrtc/api/androidvideocapturer.cc

 /*
  *  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.
  */
 
@@ skipping 46 matching lines @@
     buffer_ = nullptr;
     captured_frame_.width = 0;
     captured_frame_.height = 0;
     captured_frame_.time_stamp = 0;
   }
 
   const cricket::CapturedFrame* GetCapturedFrame() const {
     return &captured_frame_;
   }
 
+  std::unique_ptr<cricket::VideoFrame> CreateCroppedAndScaledFrame(
+      const cricket::CapturedFrame* input_frame,
+      int crop_x,
+      int crop_y,
+      int crop_width,
+      int crop_height,
+      int dst_width,
+      int dst_height) const override {
+    // Check that input_frame is actually our frame.
+    RTC_CHECK(input_frame == &captured_frame_);
+    // TODO(nisse): Must handle texture frames too.

[perkj_webrtc, 2016/05/16 06:48:46]

I think you have to do this now. CreateAliasedFrame handles textures but since
you override CreateCroppedAndScaledFrame it will not be called?

+    RTC_CHECK(buffer_->native_handle() == nullptr);
+
+    rtc::scoped_refptr<VideoFrameBuffer> scaled_buffer;
+    if (dst_width == crop_width && dst_height == crop_height) {
+      if (dst_width == buffer_->width() && dst_height == buffer_->height()) {
+        scaled_buffer = buffer_;
+      } else {
+        scaled_buffer = WrappedI420Buffer::ShallowCrop(
+            buffer_, crop_x, crop_y, dst_width, dst_height);
+      }
+    }
+    else {
+      scaled_buffer = I420Buffer::CropAndScale(
+          buffer_, crop_x, crop_y, crop_width, crop_height,
+          dst_width, dst_height);
+    }
+    std::unique_ptr<cricket::VideoFrame> frame(
+        new cricket::WebRtcVideoFrame(scaled_buffer,
+                                      input_frame->time_stamp,
+                                      input_frame->rotation));
+    return apply_rotation_ ? std::unique_ptr<cricket::VideoFrame>(
+        frame->GetCopyWithRotationApplied()->Copy())

[perkj_webrtc, 2016/05/16 06:48:46]

nit: Should there be a TODO here to fix GetCopyWithRotationApplied()->Copy()) ?
ie- should GetCopyWithRotationApplied() return a new I420Buffer  so you don't
need to call Copy? The capturer  could potentially cash the rotated buffer if it
has multiple sinks. 

(or we we just pretend that we have not seen this funny thing at the
moment.....)  

+        : std::move(frame);
+  }
+
   cricket::VideoFrame* CreateAliasedFrame(
       const cricket::CapturedFrame* captured_frame,
       int dst_width,
       int dst_height) const override {
     // Check that captured_frame is actually our frame.
     RTC_CHECK(captured_frame == &captured_frame_);
     RTC_CHECK(buffer_->native_handle() == nullptr);
 
     std::unique_ptr<cricket::VideoFrame> frame(new cricket::WebRtcVideoFrame(
         ShallowCenterCrop(buffer_, dst_width, dst_height),
@@ skipping 121 matching lines @@
 
 bool AndroidVideoCapturer::GetBestCaptureFormat(
     const cricket::VideoFormat& desired,
     cricket::VideoFormat* best_format) {
   // Delegate this choice to VideoCapturer.startCapture().
   *best_format = desired;
   return true;
 }
 
 }  // namespace webrtc