RESOURCE_UTILIZATION in VideoFrameMetadata, a consumer feedback signal.

content/browser/renderer_host/media/video_capture_controller.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 "content/browser/renderer_host/media/video_capture_controller.h"
 
 #include <map>
 #include <set>
 
 #include "base/bind.h"
@@ skipping 10 matching lines @@
 #include "content/public/common/content_switches.h"
 #include "gpu/command_buffer/common/mailbox_holder.h"
 #include "media/base/video_frame.h"
 
 #if !defined(OS_ANDROID)
 #include "content/browser/compositor/image_transport_factory.h"
 #endif
 
 using media::VideoCaptureFormat;
 using media::VideoFrame;
+using media::VideoFrameMetadata;
 
 namespace content {
 
 namespace {
 
 static const int kInfiniteRatio = 99999;
 
 #define UMA_HISTOGRAM_ASPECT_RATIO(name, width, height) \
     UMA_HISTOGRAM_SPARSE_SLOWLY( \
         name, \
@@ skipping 186 matching lines @@
   if (client) {
     client->session_closed = true;
     client->event_handler->OnEnded(client->controller_id);
   }
 }
 
 void VideoCaptureController::ReturnBuffer(
     VideoCaptureControllerID id,
     VideoCaptureControllerEventHandler* event_handler,
     int buffer_id,
-    uint32 sync_point) {
+    uint32 sync_point,
+    double consumer_resource_utilization) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   ControllerClient* client = FindClient(id, event_handler, controller_clients_);
 
   // If this buffer is not held by this client, or this client doesn't exist
   // in controller, do nothing.
   ControllerClient::ActiveBufferMap::iterator iter;
   if (!client || (iter = client->active_buffers.find(buffer_id)) ==
                      client->active_buffers.end()) {
     NOTREACHED();
     return;
   }
+
+  // Set the RESOURCE_UTILIZATION to the maximum of those provided by each

[hubbe, 2015/06/04 22:08:53]

This comment is confusing me a bit as it seems to suggest that there are
multiple consumers of the frame...

There is definitely two different sources of resource_utilization here though,
perhaps the comment can clarify where they come from?

[miu, 2015/06/06 00:29:22]

There are!  :)  Throughout the VideoCaptureController, this is a known part of
the design.

Clarified the comment, in that multiple calls of the method are coming from
different consumers that all reference the same VideoFrame.

+  // consumer.  A producer of the VideoFrame may check this value to make
+  // quality versus performance trade-off decisions.
   scoped_refptr<VideoFrame> frame = iter->second;
+  if (std::isfinite(consumer_resource_utilization) &&
+      consumer_resource_utilization >= 0.0) {
+    double resource_utilization = -1.0;
+    if (frame->metadata()->GetDouble(VideoFrameMetadata::RESOURCE_UTILIZATION,
+                                     &resource_utilization)) {
+      frame->metadata()->SetDouble(VideoFrameMetadata::RESOURCE_UTILIZATION,
+                                   std::max(consumer_resource_utilization,
+                                            resource_utilization));
+    } else {
+      frame->metadata()->SetDouble(VideoFrameMetadata::RESOURCE_UTILIZATION,
+                                   consumer_resource_utilization);
+    }
+  }
+
   client->active_buffers.erase(iter);
   buffer_pool_->RelinquishConsumerHold(buffer_id, 1);
 
 #if defined(OS_ANDROID)
   DCHECK_EQ(0u, sync_point);
 #endif
   if (sync_point)
     BrowserThread::PostTask(BrowserThread::UI,
                             FROM_HERE,
                             base::Bind(&ReturnVideoFrame, frame, sync_point));
@@ skipping 152 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   int active_client_count = 0;
   for (ControllerClient* client : controller_clients_) {
     if (!client->paused)
       ++active_client_count;
   }
   return active_client_count;
 }
 
 }  // namespace content