Fix DCHECKs in V4l2VideoDevice.

media/base/video_frame.h

 // 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.
 
 #ifndef MEDIA_BASE_VIDEO_FRAME_H_
 #define MEDIA_BASE_VIDEO_FRAME_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 201 matching lines @@
 
   // Returns the required allocation size for a (tightly packed) plane of the
   // given coded size and format.
   static size_t PlaneAllocationSize(Format format,
                                     size_t plane,
                                     const gfx::Size& coded_size);
 
   // Returns horizontal bits per pixel for given |plane| and |format|.
   static int PlaneHorizontalBitsPerPixel(Format format, size_t plane);
 
+  // Returns the number of bytes per row for the given plane, format, and width.
+  // This refers to the bytes representing frame data scanlines without stride

[Pawel Osciak, 2014/08/18 07:52:03]

We do align the given width though in the impl...

[wuchengli, 2014/08/18 09:09:00]

It refers only to the stride. The original function comments is at line 237.
I'll leave it as is...

[Pawel Osciak, 2014/08/20 10:46:06]

The issue is that it used to not take width, so it returned the result for row
bytes of actual instance of VF.
This method however takes width and aligns it if needed. This is unexpected,
especially since this doc says "without padding". So it suggests width is
unchanged. Please instead say that width may be aligned to format requirements.

[wuchengli, 2014/08/22 05:32:05]

Done.

+  // padding.
+  static int RowBytes(size_t plane, Format format, int width);
+
   Format format() const { return format_; }
 
   const gfx::Size& coded_size() const { return coded_size_; }
   const gfx::Rect& visible_rect() const { return visible_rect_; }
   const gfx::Size& natural_size() const { return natural_size_; }
 
   int stride(size_t plane) const;
 
   // Returns the number of bytes per row and number of rows for a given plane.
   //
@@ skipping 45 matching lines @@
   // VideoFrame.
   // This method is thread safe. Both blink and compositor threads can call it.
   void UpdateReleaseSyncPoint(SyncPointClient* client);
 
   // Used to keep a running hash of seen frames.  Expects an initialized MD5
   // context.  Calls MD5Update with the context and the contents of the frame.
   void HashFrameForTesting(base::MD5Context* context);
 
  private:
   friend class base::RefCountedThreadSafe<VideoFrame>;
+
+  // Returns true if |plane| is less than the number of planes for the given
+  // format. This can be used to DCHECK() plane parameters.
+  static bool IsValidPlane(size_t plane, VideoFrame::Format format);
+
   // Clients must use the static CreateFrame() method to create a new frame.
   VideoFrame(Format format,
              const gfx::Size& coded_size,
              const gfx::Rect& visible_rect,
              const gfx::Size& natural_size,
              scoped_ptr<gpu::MailboxHolder> mailbox_holder,
              base::TimeDelta timestamp,
              bool end_of_stream);
   virtual ~VideoFrame();
 
   void AllocateYUV();
 
-  // Used to DCHECK() plane parameters.
-  bool IsValidPlane(size_t plane) const;
-
   // Frame format.
   const Format format_;
 
   // Width and height of the video frame, in pixels. This must include pixel
   // data for the whole image; i.e. for YUV formats with subsampled chroma
   // planes, in the case that the visible portion of the image does not line up
   // on a sample boundary, |coded_size_| must be rounded up appropriately and
   // the pixel data provided for the odd pixels.
   const gfx::Size coded_size_;
 
@@ skipping 36 matching lines @@
   uint32 release_sync_point_;
 
   const bool end_of_stream_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_