Add 4k HW decode override flag and support larger bitstream buffers in V4L2VDA.

content/common/gpu/media/v4l2_video_decode_accelerator.h

 // Copyright 2014 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.
 //
 // This file contains an implementation of VideoDecodeAccelerator
 // that utilizes hardware video decoders, which expose Video4Linux 2 API
 // (http://linuxtv.org/downloads/v4l-dvb-apis/).
 
 #ifndef CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_
 #define CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_
@@ skipping 87 matching lines @@
 
   // VideoDecodeAcceleratorImpl implementation.
   virtual bool CanDecodeOnIOThread() OVERRIDE;
 
  private:
   // These are rather subjectively tuned.
   enum {
     kInputBufferCount = 8,
     // TODO(posciak): determine input buffer size based on level limits.
     // See http://crbug.com/255116.
-    kInputBufferMaxSize = 1024 * 1024,
+    // Input bitstream buffer size for up to 1080p streams.
+    kInputBufferMaxSizeFor1080p = 1024 * 1024,
+    // Input bitstream buffer size for up to 4k streams.
+    kInputBufferMaxSizeFor4k = 4 * kInputBufferMaxSizeFor1080p,
     // Number of output buffers to use for each VDA stage above what's required
     // by the decoder (e.g. DPB size, in H264).  We need
     // media::limits::kMaxVideoFrames to fill up the GpuVideoDecode pipeline,
     // and +1 for a frame in transit.
     kDpbOutputBufferExtraCount = media::limits::kMaxVideoFrames + 1,
   };
 
   // Internal state of the decoder.
   enum State {
     kUninitialized,      // Initialize() not yet called.
@@ skipping 317 matching lines @@
 
   // The WeakPtrFactory for |weak_this_|.
   base::WeakPtrFactory<V4L2VideoDecodeAccelerator> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(V4L2VideoDecodeAccelerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_