New method CreateScaledFrame in the VideoFrameFactory interface.

webrtc/media/engine/webrtcvideoframefactory.cc

 /*
  *  Copyright (c) 2014 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 <memory>
 
+#include "libyuv/convert.h"
+#include "libyuv/scale.h"
+
 #include "webrtc/base/logging.h"
+// #include "webrtc/common_video/include/video_frame_buffer.h"

[magjed_webrtc, 2016/05/09 10:58:08]

remove if not used

[nisse-webrtc, 2016/05/09 11:06:01]

Done.

 #include "webrtc/media/engine/webrtcvideoframe.h"
 #include "webrtc/media/engine/webrtcvideoframefactory.h"
 
+// TODO(nisse): Needed for the struct CapturedFrame. Move declaration
+// to videoframefactory.h instead?
+#include "webrtc/media/base/videocapturer.h"
+
 namespace cricket {
 
+std::unique_ptr<VideoFrame> WebRtcVideoFrameFactory::CreateScaledFrame(
+    const CapturedFrame* input_frame,
+    int width,
+    int height) const {
+  webrtc::VideoRotation rotation = input_frame->rotation;
+  int rotated_width;
+  int rotated_height;
+  if (apply_rotation_ && (rotation == webrtc::kVideoRotation_90 ||
+                          rotation == webrtc::kVideoRotation_270)) {
+    rotated_width = input_frame->height;
+    rotated_height = input_frame->width;
+  } else {
+    rotated_width = input_frame->width;
+    rotated_height = input_frame->height;
+  }
+  uint32_t format = CanonicalFourCC(input_frame->fourcc);

[magjed_webrtc, 2016/05/09 10:58:08]

Move this to the line above libyuv::ConvertToI420.

[nisse-webrtc, 2016/05/09 11:06:01]

Done.

+  rtc::scoped_refptr<webrtc::I420Buffer> buffer(
+      new rtc::RefCountedObject<webrtc::I420Buffer>(rotated_width,
+                                                    rotated_height));
+
+  // TODO(nisse): Do center crop if needed to preserve aspect ratio.

[magjed_webrtc, 2016/05/09 10:58:08]

I would like if you implemented this immediately. Maybe the name should be
changed as well? Also, if we want all implementations to center crop to preserve
aspect ratio, we should document it in the interface.

[nisse-webrtc, 2016/05/09 11:06:01]

Ok, I'll give it a try.

+  // Old code carried a comment saying that MJPG can only be cropped
+  // vertically, and disabled cropping in this case.
+
+  // Color space conversion, and rotation.
+  int r = libyuv::ConvertToI420(
+      static_cast<const uint8_t*>(input_frame->data), input_frame->data_size,
+      buffer->MutableDataY(), buffer->StrideY(),
+      buffer->MutableDataU(), buffer->StrideU(),
+      buffer->MutableDataV(), buffer->StrideV(),
+      0, 0, /* No cropping. */
+      buffer->width(), buffer->height(),
+      rotated_width, rotated_height,
+      static_cast<libyuv::RotationMode>(
+          apply_rotation_ ? rotation : webrtc::kVideoRotation_0),
+      format);
+  if (r) {
+    LOG(LS_ERROR) << "Error parsing format: " << GetFourccName(format)
+                  << " return code : " << r;
+    return nullptr;
+  }
+
+  // Scaling, if needed. Currently doesn't respect aspect ratio.
+  if (rotated_width != width || rotated_height != height) {
+    rtc::scoped_refptr<webrtc::I420Buffer> scaled(
+        new rtc::RefCountedObject<webrtc::I420Buffer>(width, height));
+
+    if (libyuv::I420Scale(buffer->DataY(), buffer->StrideY(),
+                          buffer->DataU(), buffer->StrideU(),
+                          buffer->DataV(), buffer->StrideV(),
+                          buffer->width(), buffer->height(),
+                          scaled->MutableDataY(), scaled->StrideY(),
+                          scaled->MutableDataU(), scaled->StrideU(),
+                          scaled->MutableDataV(), scaled->StrideV(),
+                          scaled->width(), scaled->height(),
+                          libyuv::kFilterBox) < 0) {
+      LOG(LS_ERROR) << "I420Scale failed: src size "
+                    << buffer->width() << " x " << buffer->height()
+                    << ", dst size: "
+                    << scaled->width() << " x " << scaled->height();
+      return nullptr;
+    }
+    buffer = scaled;
+  }
+  return std::unique_ptr<VideoFrame>(new WebRtcVideoFrame(
+      buffer, apply_rotation_ ? webrtc::kVideoRotation_0 : rotation,
+      input_frame->time_stamp / rtc::kNumNanosecsPerMicrosec));
+}
+
 VideoFrame* WebRtcVideoFrameFactory::CreateAliasedFrame(
     const CapturedFrame* aliased_frame, int width, int height) const {
   std::unique_ptr<WebRtcVideoFrame> frame(new WebRtcVideoFrame());
   if (!frame->Init(aliased_frame, width, height, apply_rotation_)) {
     LOG(LS_ERROR) <<
         "Failed to create WebRtcVideoFrame in CreateAliasedFrame.";
     return NULL;
   }
   return frame.release();
 }
 
 }  // namespace cricket