Extend media glue code to support the VideoToolbox cast video encoder.

media/base/mac/videotoolbox_glue.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.
+
+#ifndef MEDIA_BASE_MAC_VIDEOTOOLBOX_GLUE_H_
+#define MEDIA_BASE_MAC_VIDEOTOOLBOX_GLUE_H_
+
+#include "base/basictypes.h"
+#include "media/base/mac/coremedia_glue.h"
+#include "media/base/media_export.h"
+
+// VideoToolbox API is available in OS X 10.9 and iOS 8 (10.8 has support for
+// software encoding, but this class exposes the 10.9 API level). Chromium
+// requires OS X 10.6 or iOS 6. Linking with VideoToolbox therefore has to
+// happen at runtime. This class is defined to try and load the VideoToolbox
+// library. If it succeeds, clients can use VideoToolbox via this class.
+class MEDIA_EXPORT VideoToolboxGlue {
+ public:
+  class Loader;

[Robert Sesek, 2014/09/12 16:16:16]

Move to private: ?

[jfroy, 2014/09/12 17:11:46]

Loader is the lazy instance class in the implementation and needs to be a public
member to declare the static lazy instance variable. I wasn't sure if this was
better or worse than declaring Loader in the private section along with the
static lazy instance variable (i.e. a class static vs a file static). Both are
ugly exposé of the guts.

+
+  // Returns a glue object if VideoToolbox is supported or null otherwise.
+  // Using a glue object allows to avoid expensive atomic operations on every
+  // function call. The object has process life duration and must not be
+  // deleted.
+  static const VideoToolboxGlue* Get();
+
+  // Originally from VTErrors.h
+  typedef UInt32 VTEncodeInfoFlags;
+  enum {
+    kVTEncodeInfo_Asynchronous = 1UL << 0,
+    kVTEncodeInfo_FrameDropped = 1UL << 1,
+  };
+
+  // Originally from VTCompressionSession.h
+  typedef struct OpaqueVTCompressionSession* VTCompressionSessionRef;
+  typedef void (*VTCompressionOutputCallback)(
+      void* outputCallbackRefCon,
+      void* sourceFrameRefCon,
+      OSStatus status,
+      VTEncodeInfoFlags infoFlags,
+      CoreMediaGlue::CMSampleBufferRef sampleBuffer);
+
+  // Originally from VTSession.h
+  typedef CFTypeRef VTSessionRef;
+
+  // Originally from VTCompressionProperties.h
+  CFStringRef kVTCompressionPropertyKey_AllowFrameReordering() const;
+  CFStringRef kVTCompressionPropertyKey_AverageBitRate() const;
+  CFStringRef kVTCompressionPropertyKey_ColorPrimaries() const;
+  CFStringRef kVTCompressionPropertyKey_ExpectedFrameRate() const;
+  CFStringRef kVTCompressionPropertyKey_MaxKeyFrameInterval() const;
+  CFStringRef kVTCompressionPropertyKey_MaxKeyFrameIntervalDuration() const;
+  CFStringRef kVTCompressionPropertyKey_ProfileLevel() const;
+  CFStringRef kVTCompressionPropertyKey_RealTime() const;
+  CFStringRef kVTCompressionPropertyKey_TransferFunction() const;
+  CFStringRef kVTCompressionPropertyKey_YCbCrMatrix() const;
+
+  CFStringRef kVTEncodeFrameOptionKey_ForceKeyFrame() const;
+
+  CFStringRef kVTProfileLevel_H264_Baseline_AutoLevel() const;
+  CFStringRef kVTProfileLevel_H264_Main_AutoLevel() const;
+  CFStringRef kVTProfileLevel_H264_Extended_AutoLevel() const;
+  CFStringRef kVTProfileLevel_H264_High_AutoLevel() const;
+
+  CFStringRef
+      kVTVideoEncoderSpecification_EnableHardwareAcceleratedVideoEncoder()
+      const;
+
+  // Originally from VTCompressionSession.h
+  OSStatus VTCompressionSessionCreate(
+      CFAllocatorRef allocator,
+      int32_t width,
+      int32_t height,
+      CoreMediaGlue::CMVideoCodecType codecType,
+      CFDictionaryRef encoderSpecification,
+      CFDictionaryRef sourceImageBufferAttributes,
+      CFAllocatorRef compressedDataAllocator,
+      VTCompressionOutputCallback outputCallback,
+      void* outputCallbackRefCon,
+      VTCompressionSessionRef* compressionSessionOut) const;
+  OSStatus VTCompressionSessionEncodeFrame(
+      VTCompressionSessionRef session,
+      CVImageBufferRef imageBuffer,
+      CoreMediaGlue::CMTime presentationTimeStamp,
+      CoreMediaGlue::CMTime duration,
+      CFDictionaryRef frameProperties,
+      void* sourceFrameRefCon,
+      VTEncodeInfoFlags* infoFlagsOut) const;
+  CVPixelBufferPoolRef VTCompressionSessionGetPixelBufferPool(
+      VTCompressionSessionRef session) const;
+  void VTCompressionSessionInvalidate(VTCompressionSessionRef session) const;
+
+  // Originally from VTSession.h
+  OSStatus VTSessionSetProperty(VTSessionRef session,
+                                CFStringRef propertyKey,
+                                CFTypeRef propertyValue) const;
+
+ private:
+  struct Library;
+  VideoToolboxGlue();
+  Library* library_;
+  DISALLOW_COPY_AND_ASSIGN(VideoToolboxGlue);
+};
+
+#endif  // MEDIA_BASE_MAC_VIDEOTOOLBOX_GLUE_H_