Memory copy the VideoFrame to match the requirement for HW encoders.

media/base/video_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/video_util.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/numerics/safe_math.h"
 #include "media/base/video_frame.h"
 #include "media/base/yuv_convert.h"
+#include "third_party/libyuv/include/libyuv.h"
 
 namespace media {
 
 namespace {
 
 // Empty method used for keeping a reference to the original media::VideoFrame.
 void ReleaseOriginalFrame(const scoped_refptr<media::VideoFrame>& frame) {}
 
+// Helper to apply padding to the region outside visible rect with the repeated
+// last column / row of the visible rect.
+void FillRegionOutsideVisibleRect(uint8_t* frame,
+                                  const gfx::Size& frame_size,
+                                  const gfx::Size& visible_size) {
+  if (visible_size.IsEmpty())

[miu, 2016/05/03 19:05:43]

This just occurred to me: If coded_size is non-empty, perhaps you should still
memset(frame->data(x), 0, len) for each plane?

[xjz, 2016/05/03 23:30:15]

Done. 

+    return;
+
+  const int stride = frame_size.width();
+  if (visible_size.width() < stride) {
+    const int pad_length = stride - visible_size.width();
+    uint8_t* dst = frame + visible_size.width();
+    for (int i = 0; i < visible_size.height(); ++i, dst += stride)
+      std::memset(dst, *(dst - 1), pad_length);
+  }
+
+  if (visible_size.height() < frame_size.height()) {
+    uint8_t* dst = frame + visible_size.height() * stride;
+    uint8_t* src = dst - stride;
+    for (int i = visible_size.height(); i < frame_size.height();
+         ++i, dst += stride)
+      std::memcpy(dst, src, stride);
+  }
+}
+
 }  // namespace
 
 gfx::Size GetNaturalSize(const gfx::Size& visible_size,
                          int aspect_ratio_numerator,
                          int aspect_ratio_denominator) {
   if (aspect_ratio_denominator == 0 ||
       aspect_ratio_numerator < 0 ||
       aspect_ratio_denominator < 0)
     return gfx::Size();
 
@@ skipping 300 matching lines @@
       media::VideoFrame::WrapVideoFrame(frame, PIXEL_FORMAT_I420,
                                         frame->visible_rect(),
                                         frame->natural_size());
   if (!wrapped_frame)
     return nullptr;
   wrapped_frame->AddDestructionObserver(
       base::Bind(&ReleaseOriginalFrame, frame));
   return wrapped_frame;
 }
 
+bool I420CopyWithPadding(const VideoFrame& src_frame, VideoFrame* dst_frame) {
+  if (!dst_frame)

[miu, 2016/05/03 19:05:43]

Need to check for non-memory-backed VideoFrames:

  if (!dst_frame || !dst_frame->IsMappable())
    return false;

[xjz, 2016/05/03 23:30:15]

Done.

+    return false;
+
+  DCHECK_GE(dst_frame->coded_size().width(), src_frame.visible_rect().width());
+  DCHECK_GE(dst_frame->coded_size().height(),
+            src_frame.visible_rect().height());
+  DCHECK(dst_frame->visible_rect().origin().IsOrigin());
+
+  if (libyuv::I420Copy(src_frame.visible_data(media::VideoFrame::kYPlane),
+                       src_frame.stride(media::VideoFrame::kYPlane),
+                       src_frame.visible_data(media::VideoFrame::kUPlane),
+                       src_frame.stride(media::VideoFrame::kUPlane),
+                       src_frame.visible_data(media::VideoFrame::kVPlane),
+                       src_frame.stride(media::VideoFrame::kVPlane),
+                       dst_frame->data(media::VideoFrame::kYPlane),
+                       dst_frame->stride(media::VideoFrame::kYPlane),
+                       dst_frame->data(media::VideoFrame::kUPlane),
+                       dst_frame->stride(media::VideoFrame::kUPlane),
+                       dst_frame->data(media::VideoFrame::kVPlane),
+                       dst_frame->stride(media::VideoFrame::kVPlane),
+                       src_frame.visible_rect().width(),
+                       src_frame.visible_rect().height()))
+    return false;
+
+  // Padding the region outside the visible rect with the repeated last
+  // column / row of the visible rect. This can improve the coding efficiency.
+  FillRegionOutsideVisibleRect(dst_frame->data(media::VideoFrame::kYPlane),
+                               dst_frame->coded_size(),
+                               src_frame.visible_rect().size());
+  FillRegionOutsideVisibleRect(
+      dst_frame->data(media::VideoFrame::kUPlane),
+      VideoFrame::PlaneSize(PIXEL_FORMAT_I420, media::VideoFrame::kUPlane,
+                            dst_frame->coded_size()),
+      VideoFrame::PlaneSize(PIXEL_FORMAT_I420, media::VideoFrame::kUPlane,
+                            src_frame.visible_rect().size()));
+  FillRegionOutsideVisibleRect(
+      dst_frame->data(media::VideoFrame::kVPlane),
+      VideoFrame::PlaneSize(PIXEL_FORMAT_I420, media::VideoFrame::kVPlane,
+                            dst_frame->coded_size()),
+      VideoFrame::PlaneSize(PIXEL_FORMAT_I420, media::VideoFrame::kVPlane,
+                            src_frame.visible_rect().size()));
+  return true;
+}
+
 }  // namespace media