New method CreateScaledFrame in the VideoFrameFactory interface.

webrtc/common_video/video_frame_buffer.cc

Index: webrtc/common_video/video_frame_buffer.cc
diff --git a/webrtc/common_video/video_frame_buffer.cc b/webrtc/common_video/video_frame_buffer.cc
index 700dcaf02b7af098798eb51e344f065b232a8700..19b2bc25441b4d724265f73a9bf09e67933d9e2a 100644
--- a/webrtc/common_video/video_frame_buffer.cc
+++ b/webrtc/common_video/video_frame_buffer.cc
@@ -13,6 +13,7 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/keep_ref_until_done.h"
 #include "libyuv/convert.h"
+#include "libyuv/scale.h"
 
 // Aligning pointer to 64 bytes for improved performance, e.g. use SIMD.
 static const int kBufferAlignment = 64;
@@ -207,6 +208,56 @@ rtc::scoped_refptr<I420Buffer> I420Buffer::Copy(
   return copy;
 }
 
+rtc::scoped_refptr<I420Buffer> I420Buffer::CropAndScale(
+    const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
+    int offset_x,
+    int offset_y,
+    int crop_width,
+    int crop_height,
+    int dst_width,
+    int dst_height) {
+  RTC_CHECK_LE(crop_width, buffer->width());
+  RTC_CHECK_LE(crop_height, buffer->height());
+  RTC_CHECK_LE(crop_width + offset_x, buffer->width());
+  RTC_CHECK_LE(crop_height + offset_y, buffer->height());
+
+  rtc::scoped_refptr<I420Buffer> scaled =
+      new rtc::RefCountedObject<I420Buffer>(dst_width, dst_height);
+
+  // Make sure offset is even so that u/v plane becomes aligned.
+  // TODO(nisse): Duplicated in ShallowCrop.

[perkj_webrtc, 2016/05/16 06:48:47]

remove this todo. I am fine with this duplication.

+  const int uv_offset_x = offset_x / 2;
+  const int uv_offset_y = offset_y / 2;
+  offset_x = uv_offset_x * 2;
+  offset_y = uv_offset_y * 2;
+
+  const uint8_t* y_plane = buffer->DataY() +
+      buffer->StrideY() * offset_y + offset_x;
+  const uint8_t* u_plane = buffer->DataU() +
+      buffer->StrideU() * uv_offset_y + uv_offset_x;
+  const uint8_t* v_plane = buffer->DataV() +
+      buffer->StrideV() * uv_offset_y + uv_offset_x;
+  if (libyuv::I420Scale(y_plane, buffer->StrideY(),
+                        u_plane, buffer->StrideU(),
+                        v_plane, buffer->StrideV(),
+                        crop_width, crop_height,
+                        scaled->MutableDataY(), scaled->StrideY(),
+                        scaled->MutableDataU(), scaled->StrideU(),
+                        scaled->MutableDataV(), scaled->StrideV(),
+                        dst_width, dst_height, libyuv::kFilterBox) < 0) {
+    return nullptr;
+  }
+  return scaled;
+}
+
+rtc::scoped_refptr<I420Buffer> I420Buffer::Scale(
+    const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
+    int dst_width,
+    int dst_height) {
+  return CropAndScale(buffer, 0, 0, buffer->width(), buffer->height(),
+                      dst_width, dst_height);
+}
+
 NativeHandleBuffer::NativeHandleBuffer(void* native_handle,
                                        int width,
                                        int height)
@@ -324,22 +375,21 @@ rtc::scoped_refptr<VideoFrameBuffer> WrappedI420Buffer::NativeToI420Buffer() {
   return nullptr;
 }
 
-rtc::scoped_refptr<VideoFrameBuffer> ShallowCenterCrop(
+rtc::scoped_refptr<WrappedI420Buffer> WrappedI420Buffer::ShallowCrop(
     const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
+    int offset_x,
+    int offset_y,
     int cropped_width,
     int cropped_height) {
   RTC_CHECK(buffer->native_handle() == nullptr);
   RTC_CHECK_LE(cropped_width, buffer->width());
   RTC_CHECK_LE(cropped_height, buffer->height());
-  if (buffer->width() == cropped_width && buffer->height() == cropped_height)
-    return buffer;
 
-  // Center crop to |cropped_width| x |cropped_height|.
   // Make sure offset is even so that u/v plane becomes aligned.
-  const int uv_offset_x = (buffer->width() - cropped_width) / 4;
-  const int uv_offset_y = (buffer->height() - cropped_height) / 4;
-  const int offset_x = uv_offset_x * 2;
-  const int offset_y = uv_offset_y * 2;
+  const int uv_offset_x = offset_x / 2;
+  const int uv_offset_y = offset_y / 2;
+  offset_x = uv_offset_x * 2;
+  offset_y = uv_offset_y * 2;
 
   const uint8_t* y_plane = buffer->DataY() +
                            buffer->StrideY() * offset_y + offset_x;
@@ -355,4 +405,18 @@ rtc::scoped_refptr<VideoFrameBuffer> ShallowCenterCrop(
       rtc::KeepRefUntilDone(buffer));
 }
 
+// TODO(nisse): Used only by
+// AndroidVideoCapturer::FrameFactory::CreateAliasedFrame. Delete when
+// the CreateAliasedFrame method is removed.
+rtc::scoped_refptr<VideoFrameBuffer> ShallowCenterCrop(
+    const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
+    int cropped_width,
+    int cropped_height) {
+  return WrappedI420Buffer::ShallowCrop(
+      buffer,
+      (buffer->width() - cropped_width) / 2,
+      (buffer->height() - cropped_height) / 2,
+      cropped_width, cropped_height);
+}
+
 }  // namespace webrtc