MJPEG acceleration for video capture, browser part

content/browser/renderer_host/media/video_capture_device_client.cc

Index: content/browser/renderer_host/media/video_capture_device_client.cc
diff --git a/content/browser/renderer_host/media/video_capture_device_client.cc b/content/browser/renderer_host/media/video_capture_device_client.cc
index b739aca1967fb8176190fb2f9b0c7272d542623d..1cbfd40675959dca6569e53e65cac65af5eadeaf 100644
--- a/content/browser/renderer_host/media/video_capture_device_client.cc
+++ b/content/browser/renderer_host/media/video_capture_device_client.cc
@@ -11,6 +11,7 @@
 #include "content/browser/gpu/browser_gpu_channel_host_factory.h"
 #include "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
+#include "content/browser/renderer_host/gpu_jpeg_decoder.h"
 #include "content/browser/renderer_host/media/video_capture_buffer_pool.h"
 #include "content/browser/renderer_host/media/video_capture_controller.h"
 #include "content/common/gpu/client/context_provider_command_buffer.h"
@@ -123,6 +124,9 @@ class AutoReleaseBuffer : public media::VideoCaptureDevice::Client::Buffer {
   ClientBuffer AsClientBuffer() override {
     return buffer_handle_->AsClientBuffer();
   }
+  base::PlatformFile AsPlatformHandle() override {
+    return buffer_handle_->AsPlatformHandle();
+  }
 
  private:
   ~AutoReleaseBuffer() override { pool_->RelinquishProducerReservation(id_); }
@@ -196,13 +200,17 @@ VideoCaptureDeviceClient::VideoCaptureDeviceClient(
     const scoped_refptr<VideoCaptureBufferPool>& buffer_pool,
     const scoped_refptr<base::SingleThreadTaskRunner>& capture_task_runner)
     : controller_(controller),
+      external_jpeg_decoder_initialized_(false),
       buffer_pool_(buffer_pool),
       capture_task_runner_(capture_task_runner),
       last_captured_pixel_format_(media::PIXEL_FORMAT_UNKNOWN) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 }
 
-VideoCaptureDeviceClient::~VideoCaptureDeviceClient() {}
+VideoCaptureDeviceClient::~VideoCaptureDeviceClient() {
+  DCHECK(capture_task_runner_->BelongsToCurrentThread());
+  external_jpeg_decoder_.reset();
+}
 
 void VideoCaptureDeviceClient::OnIncomingCapturedData(
     const uint8* data,
@@ -216,6 +224,23 @@ void VideoCaptureDeviceClient::OnIncomingCapturedData(
     OnLog("Pixel format: " + media::VideoCaptureFormat::PixelFormatToString(
                                  frame_format.pixel_format));
     last_captured_pixel_format_ = frame_format.pixel_format;
+
+    if (frame_format.pixel_format == media::PIXEL_FORMAT_MJPEG &&
+        !external_jpeg_decoder_initialized_) {
+      external_jpeg_decoder_initialized_ = true;
+      if (GpuJpegDecoder::Supported()) {
+        // base::Unretained is safe because |this| outlives
+        // |external_jpeg_decoder_|.
+        external_jpeg_decoder_.reset(new GpuJpegDecoder(
+            base::Bind(&VideoCaptureDeviceClient::OnIncomingCapturedVideoFrame,

[piman, 2015/06/05 23:07:51]

Maybe you can bind to DoIncomingCapturedVideoFrameOnIOThread directly to avoid
the extra PostTask?

That way you don't need Unretained(this) - you can pass the controller_ WeakPtr
directly.

[kcwu, 2015/06/17 14:35:37]

Done.

+                       base::Unretained(this)),
+            // TODO(kcwu): fallback to software decode if error.
+            base::Bind(&VideoCaptureDeviceClient::OnError,

[piman, 2015/06/05 23:07:51]

Same here, bind to DoErrorOnIOThread?

[kcwu, 2015/06/17 14:35:37]

Not exactly. VideoCaptureDeviceClient::OnError = OnLog + DoErrorOnIOThread.

Since error callback is not on the critical path, I'd prefer less code with the
cost of extra PostTask. What do you think?

+                       base::Unretained(this))));
+        if (!external_jpeg_decoder_->Initialize())
+          external_jpeg_decoder_.reset();
+      }
+    }
   }
 
   if (!frame_format.IsValid())
@@ -329,6 +354,14 @@ void VideoCaptureDeviceClient::OnIncomingCapturedData(
   // paddings and/or alignments, but it cannot be smaller.
   DCHECK_GE(static_cast<size_t>(length), frame_format.ImageAllocationSize());
 
+  if (external_jpeg_decoder_ &&
+      frame_format.pixel_format == media::PIXEL_FORMAT_MJPEG && rotation == 0 &&
+      !flip) {
+    external_jpeg_decoder_->DecodeCapturedData(data, length, frame_format,
+                                               timestamp, buffer.Pass());
+    return;
+  }
+
   if (libyuv::ConvertToI420(data,
                             length,
                             yplane,