MediaRecorder: use VideoTrackRecorder::GetPreferredCodecId() when available

content/renderer/media/video_track_recorder.cc

Index: content/renderer/media/video_track_recorder.cc
diff --git a/content/renderer/media/video_track_recorder.cc b/content/renderer/media/video_track_recorder.cc
index 011c633e3d1e90f8db0bf692b6185ad8c67ff4b1..eebcb327fb34d68d82a3b932f459f486c6495947 100644
--- a/content/renderer/media/video_track_recorder.cc
+++ b/content/renderer/media/video_track_recorder.cc
@@ -60,60 +60,98 @@ const int kVEADefaultBitratePerPixel = 2;
 // encoders.
 const int kVEAEncoderOutputBufferCount = 4;
 
-static struct {
-  VideoTrackRecorder::CodecId codec_id;
-  media::VideoCodecProfile min_profile;
-  media::VideoCodecProfile max_profile;
-} const kSupportedVideoCodecIdToProfile[] = {
-    {VideoTrackRecorder::CodecId::VP8,
-     media::VP8PROFILE_MIN,
-     media::VP8PROFILE_MAX},
-    {VideoTrackRecorder::CodecId::VP9,
-     media::VP9PROFILE_MIN,
-     media::VP9PROFILE_MAX},
-    {VideoTrackRecorder::CodecId::H264,
-     media::H264PROFILE_MIN,
-     media::H264PROFILE_MAX}};
-
-// Returns the corresponding codec profile from VEA supported codecs. If no
-// profile is found, returns VIDEO_CODEC_PROFILE_UNKNOWN.
-media::VideoCodecProfile CodecIdToVEAProfile(
-    content::VideoTrackRecorder::CodecId codec) {
-  // See https://crbug.com/616659.
+using CodecId = VideoTrackRecorder::CodecId;
+
+// Class to encapsulate the enumeration of CodecIds/VideoCodecProfiles supported
+// by the VEA underlying platform. Provides methods to query the preferred
+// CodecId and to check if a given CodecId is supported.
+class CodecEnumerator {
+ public:
+  CodecEnumerator();
+  ~CodecEnumerator() = default;
+
+  // Get the first CodecId that has an associated VEA VideoCodecProfile, or VP8.
+  CodecId GetPreferredCodecId();
+
+  // Returns the VEA VideoCodedProfile for a given CodecId, if supported, or
+  // VIDEO_CODEC_PROFILE_UNKNOWN otherwise.
+  media::VideoCodecProfile CodecIdToVEAProfile(CodecId codec);
+
+ private:
+  static const struct CodecIdAndVEAProfile {
+    CodecId codec_id;
+    media::VideoCodecProfile min_profile;
+    media::VideoCodecProfile max_profile;
+  } constexpr kCodecIdAndVEAProfiles[] = {
+      {CodecId::VP8, media::VP8PROFILE_MIN, media::VP8PROFILE_MAX},
+      {CodecId::VP9, media::VP9PROFILE_MIN, media::VP9PROFILE_MAX},
+      {CodecId::H264, media::H264PROFILE_MIN, media::H264PROFILE_MAX}};
+
+  // A map of VEA-supported CodecId-and-VEA-profile pairs.
+  std::map<CodecId, media::VideoCodecProfile> codec_id_to_profile_;
+
+  DISALLOW_COPY_AND_ASSIGN(CodecEnumerator);
+};
+
+constexpr CodecEnumerator::CodecIdAndVEAProfile
+    CodecEnumerator::kCodecIdAndVEAProfiles[];
+
+static base::LazyInstance<CodecEnumerator>::Leaky g_codec_enumerator =
+    LAZY_INSTANCE_INITIALIZER;
+
+CodecEnumerator::CodecEnumerator() {
+  static_assert(
+      arraysize(kCodecIdAndVEAProfiles) == static_cast<int>(CodecId::LAST),
+      "|kCodecIdAndVEAProfiles| should consider all CodecIds");
 #if defined(OS_CHROMEOS)
-  return media::VIDEO_CODEC_PROFILE_UNKNOWN;
-#endif  // defined(OS_CHROMEOS)
+  // See https://crbug.com/616659.
+  return;
+#endif
 
-// See https://crbug.com/653864.
 #if defined(OS_ANDROID)
-  return media::VIDEO_CODEC_PROFILE_UNKNOWN;
-#endif  // defined(OS_ANDROID)
+  // See https://crbug.com/653864.
+  return;
+#endif
 
   content::RenderThreadImpl* const render_thread_impl =
       content::RenderThreadImpl::current();
   if (!render_thread_impl) {
-    DVLOG(3) << "Couldn't access the render thread";
-    return media::VIDEO_CODEC_PROFILE_UNKNOWN;
+    DVLOG(2) << "Couldn't access the render thread";
+    return;
   }
 
   media::GpuVideoAcceleratorFactories* const gpu_factories =
       render_thread_impl->GetGpuFactories();
   if (!gpu_factories || !gpu_factories->IsGpuVideoAcceleratorEnabled()) {
-    DVLOG(3) << "Couldn't initialize GpuVideoAcceleratorFactories";
-    return media::VIDEO_CODEC_PROFILE_UNKNOWN;
+    DVLOG(2) << "Couldn't initialize GpuVideoAcceleratorFactories";
+    return;
   }
 
   const media::VideoEncodeAccelerator::SupportedProfiles& vea_profiles =
       gpu_factories->GetVideoEncodeAcceleratorSupportedProfiles();
   for (const auto& vea_profile : vea_profiles) {
-    for (const auto& supported_profile : kSupportedVideoCodecIdToProfile) {
-      if (codec == supported_profile.codec_id &&
-          vea_profile.profile >= supported_profile.min_profile &&
-          vea_profile.profile <= supported_profile.max_profile)
-        return vea_profile.profile;
+    for (auto& codec_id_and_profile : kCodecIdAndVEAProfiles) {
+      if (vea_profile.profile >= codec_id_and_profile.min_profile &&
+          vea_profile.profile <= codec_id_and_profile.max_profile) {
+        DVLOG(2) << media::GetProfileName(vea_profile.profile) << " supported";
+        codec_id_to_profile_.emplace(
+            std::make_pair(codec_id_and_profile.codec_id, vea_profile.profile));

[emircan, 2017/01/11 22:11:05]

codec_id_to_profile_.emplace(codec_id_and_profile.codec_id,
vea_profile.profile);

[emircan, 2017/01/11 22:11:05]

Note that this would take the min profile if there is multiple. For instance, if
H264_BASELINE and H264_MAIN is supported, it would see that key exists in the
second pass and emplace() would return false.

[mcasas, 2017/01/11 22:30:16]

Done.

[mcasas, 2017/01/11 22:30:16]

Gotcha. That's ok for the time being.
We'll be keeping an eye out, specially as 
we enable more platforms.

[mcasas, 2017/01/12 00:20:54]

Some bots were unhappy, see e.g. linux_chromium_compile_rel_ng:

video_track_recorder.cc:137:30: error: no member named 'emplace' in
'std::map<content::VideoTrackRecorder::CodecId, media::VideoCodecProfile,
std::less<content::VideoTrackRecorder::CodecId>, std::allocator<std::pair<const
content::VideoTrackRecorder::CodecId, media::VideoCodecProfile> > >'
        codec_id_to_profile_.emplace(
        ~~~~~~~~~~~~~~~~~~~~ ^

+      }
     }
   }
-  return media::VIDEO_CODEC_PROFILE_UNKNOWN;
+}
+
+CodecId CodecEnumerator::GetPreferredCodecId() {
+  if (codec_id_to_profile_.empty())
+    return CodecId::VP8;
+  return codec_id_to_profile_.begin()->first;
+}
+
+media::VideoCodecProfile CodecEnumerator::CodecIdToVEAProfile(CodecId codec) {
+  const auto profile = codec_id_to_profile_.find(codec);
+  return profile == codec_id_to_profile_.end()
+             ? media::VIDEO_CODEC_PROFILE_UNKNOWN
+             : profile->second;
 }
 
 }  // anonymous namespace
@@ -1075,6 +1113,11 @@ void H264Encoder::ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) {
 
 }  // anonymous namespace
 
+// static
+VideoTrackRecorder::CodecId VideoTrackRecorder::GetPreferredCodecId() {
+  return g_codec_enumerator.Get().GetPreferredCodecId();
+}
+
 VideoTrackRecorder::VideoTrackRecorder(
     CodecId codec,
     const blink::WebMediaStreamTrack& track,
@@ -1143,7 +1186,8 @@ void VideoTrackRecorder::InitializeEncoder(
   MediaStreamVideoSink::DisconnectFromTrack();
 
   const gfx::Size& input_size = frame->visible_rect().size();
-  const auto& vea_supported_profile = CodecIdToVEAProfile(codec);
+  const auto& vea_supported_profile =
+      g_codec_enumerator.Get().CodecIdToVEAProfile(codec);
   if (vea_supported_profile != media::VIDEO_CODEC_PROFILE_UNKNOWN &&
       input_size.width() >= kVEAEncoderMinResolutionWidth &&
       input_size.height() >= kVEAEncoderMinResolutionHeight) {
@@ -1162,7 +1206,7 @@ void VideoTrackRecorder::InitializeEncoder(
         encoder_ = new VpxEncoder(codec == CodecId::VP9,
                                   on_encoded_video_callback, bits_per_second);
         break;
-      default:
+      case CodecId::LAST:
         NOTREACHED() << "Unsupported codec";
     }
   }