media/video/capture/mac/coremedia_glue.mm

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/video/capture/mac/coremedia_glue.h"
   6
   7 #include <dlfcn.h>
   8
   9 #include "base/logging.h"
  10 #include "base/lazy_instance.h"
  11
  12 namespace {
  13
  14 // This class is used to retrieve some CoreMedia library functions. It must be
  15 // used as a LazyInstance so that it is initialised once and in a thread-safe
  16 // way. Normally no work is done in constructors: LazyInstance is an exception.
  17 class CoreMediaLibraryInternal {
  18  public:
  19   typedef CoreMediaGlue::CMTime (*CMTimeMakeMethod)(int64_t, int32_t);
  20   typedef CVImageBufferRef (*CMSampleBufferGetImageBufferMethod)(
  21       CoreMediaGlue::CMSampleBufferRef);
  22   typedef FourCharCode (*CMFormatDescriptionGetMediaSubTypeMethod)(
  23       CoreMediaGlue::CMFormatDescriptionRef desc);
  24   typedef CoreMediaGlue::CMVideoDimensions
  25       (*CMVideoFormatDescriptionGetDimensionsMethod)(
  26           CoreMediaGlue::CMVideoFormatDescriptionRef videoDesc);
  27
  28   CoreMediaLibraryInternal() {
  29     NSBundle* bundle = [NSBundle
  30         bundleWithPath:@"/System/Library/Frameworks/CoreMedia.framework"];
  31
  32     const char* path = [[bundle executablePath] fileSystemRepresentation];
  33     CHECK(path);
  34     void* library_handle = dlopen(path, RTLD_LAZY | RTLD_LOCAL);
  35     CHECK(library_handle) << dlerror();
  36
  37     // Now extract the methods.
  38     cm_time_make_ = reinterpret_cast<CMTimeMakeMethod>(
  39         dlsym(library_handle, "CMTimeMake"));
  40     CHECK(cm_time_make_) << dlerror();
  41
  42     cm_sample_buffer_get_image_buffer_method_ =
  43         reinterpret_cast<CMSampleBufferGetImageBufferMethod>(
  44             dlsym(library_handle, "CMSampleBufferGetImageBuffer"));
  45     CHECK(cm_sample_buffer_get_image_buffer_method_) << dlerror();
  46
  47     cm_format_description_get_media_sub_type_method_ =
  48         reinterpret_cast<CMFormatDescriptionGetMediaSubTypeMethod>(
  49             dlsym(library_handle, "CMFormatDescriptionGetMediaSubType"));
  50     CHECK(cm_format_description_get_media_sub_type_method_) << dlerror();
  51
  52     cm_video_format_description_get_dimensions_method_ =
  53         reinterpret_cast<CMVideoFormatDescriptionGetDimensionsMethod>(
  54             dlsym(library_handle, "CMVideoFormatDescriptionGetDimensions"));
  55     CHECK(cm_video_format_description_get_dimensions_method_) << dlerror();
  56   }
  57
  58   const CMTimeMakeMethod& cm_time_make() const { return cm_time_make_; }
  59   const CMSampleBufferGetImageBufferMethod&
  60       cm_sample_buffer_get_image_buffer_method() const {
  61     return cm_sample_buffer_get_image_buffer_method_;
  62   }
  63   const CMFormatDescriptionGetMediaSubTypeMethod&
  64       cm_format_description_get_media_sub_type_method() const {
  65     return cm_format_description_get_media_sub_type_method_;
  66   }
  67   const CMVideoFormatDescriptionGetDimensionsMethod&
  68       cm_video_format_description_get_dimensions_method() const {
  69     return cm_video_format_description_get_dimensions_method_;
  70   }
  71
  72  private:
  73   CMTimeMakeMethod cm_time_make_;
  74   CMSampleBufferGetImageBufferMethod cm_sample_buffer_get_image_buffer_method_;
  75   CMFormatDescriptionGetMediaSubTypeMethod
  76       cm_format_description_get_media_sub_type_method_;
  77   CMVideoFormatDescriptionGetDimensionsMethod
  78       cm_video_format_description_get_dimensions_method_;
  79
  80   DISALLOW_COPY_AND_ASSIGN(CoreMediaLibraryInternal);
  81 };
  82
  83 }  // namespace
  84
  85 static base::LazyInstance<CoreMediaLibraryInternal> g_coremedia_handle =
  86     LAZY_INSTANCE_INITIALIZER;
  87
  88 // static
  89 CoreMediaGlue::CMTime CoreMediaGlue::CMTimeMake(int64_t value,
  90                                                 int32_t timescale) {
  91   return g_coremedia_handle.Get().cm_time_make()(value, timescale);
  92 }
  93
  94 // static
  95 CVImageBufferRef CoreMediaGlue::CMSampleBufferGetImageBuffer(
  96     CMSampleBufferRef buffer) {
  97   return g_coremedia_handle.Get().cm_sample_buffer_get_image_buffer_method()(
  98       buffer);
  99 }
 100
 101 // static
 102 FourCharCode CoreMediaGlue::CMFormatDescriptionGetMediaSubType(
 103       CMFormatDescriptionRef desc) {
 104   return g_coremedia_handle.Get()
 105       .cm_format_description_get_media_sub_type_method()(desc);
 106 }
 107
 108 // static
 109 CoreMediaGlue::CMVideoDimensions
 110     CoreMediaGlue::CMVideoFormatDescriptionGetDimensions(
 111         CMVideoFormatDescriptionRef videoDesc) {
 112   return g_coremedia_handle.Get()
 113       .cm_video_format_description_get_dimensions_method()(videoDesc);
 114 }