Expose codec implementation names in stats.

Used to distinguish between software/hardware encoders/decoders and
other implementation differences. Useful for tracking quality
regressions related to specific implementations.

BUG=webrtc:4897
R=hta@webrtc.org, mflodman@webrtc.org, stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1406903002 .

Cr-Commit-Position: refs/heads/master@{#11084}

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_decoder.cc

@@ -266,6 +266,10 @@ void H264VideoToolboxDecoder::SetVideoFormat(
   }
 }
 
+const char* H264VideoToolboxDecoder::ImplementationName() const {
+  return "VideoToolbox";
+}
+
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_decoder.h

@@ -45,6 +45,8 @@ class H264VideoToolboxDecoder : public H264Decoder {
 
   int Reset() override;
 
+  const char* ImplementationName() const override;
+
  private:
   int ResetDecompressionSession();
   void ConfigureDecompressionSession();

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.cc

@@ -434,6 +434,10 @@ void H264VideoToolboxEncoder::DestroyCompressionSession() {
   }
 }
 
+const char* H264VideoToolboxEncoder::ImplementationName() const {
+  return "VideoToolbox";
+}
+
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.h

@@ -48,6 +48,8 @@ class H264VideoToolboxEncoder : public H264Encoder {
 
   int Release() override;
 
+  const char* ImplementationName() const override;
+
  private:
   int ResetCompressionSession();
   void ConfigureCompressionSession();

webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc

@@ -301,6 +301,10 @@ int VP8EncoderImpl::SetRates(uint32_t new_bitrate_kbit,
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* VP8EncoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 void VP8EncoderImpl::SetStreamState(bool send_stream,
                                             int stream_idx) {
   if (send_stream && !send_stream_[stream_idx]) {
@@ -1398,6 +1402,10 @@ int VP8DecoderImpl::Release() {
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* VP8DecoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 int VP8DecoderImpl::CopyReference(VP8DecoderImpl* copy) {
   // The type of frame to copy should be set in ref_frame_->frame_type
   // before the call to this function.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.h

@@ -58,6 +58,8 @@ class VP8EncoderImpl : public VP8Encoder {
 
   void OnDroppedFrame() override {}
 
+  const char* ImplementationName() const override;
+
  private:
   void SetupTemporalLayers(int num_streams, int num_temporal_layers,
                            const VideoCodec& codec);
@@ -135,6 +137,8 @@ class VP8DecoderImpl : public VP8Decoder {
   int Release() override;
   int Reset() override;
 
+  const char* ImplementationName() const override;
+
  private:
   // Copy reference image from this _decoder to the _decoder in copyTo. Set
   // which frame type to copy in _refFrame->frame_type before the call to

webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc

@@ -809,6 +809,10 @@ int VP9EncoderImpl::RegisterEncodeCompleteCallback(
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* VP9EncoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 VP9Decoder* VP9Decoder::Create() {
   return new VP9DecoderImpl();
 }
@@ -980,4 +984,9 @@ int VP9DecoderImpl::Release() {
   inited_ = false;
   return WEBRTC_VIDEO_CODEC_OK;
 }
+
+const char* VP9DecoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 }  // namespace webrtc

webrtc/modules/video_coding/codecs/vp9/vp9_impl.h

@@ -47,6 +47,8 @@ class VP9EncoderImpl : public VP9Encoder {
 
   void OnDroppedFrame() override {}
 
+  const char* ImplementationName() const override;
+
   struct LayerFrameRefSettings {
     int8_t upd_buf = -1;   // -1 - no update,    0..7 - update buffer 0..7
     int8_t ref_buf1 = -1;  // -1 - no reference, 0..7 - reference buffer 0..7
@@ -148,6 +150,8 @@ class VP9DecoderImpl : public VP9Decoder {
 
   int Reset() override;
 
+  const char* ImplementationName() const override;
+
  private:
   int ReturnFrame(const vpx_image_t* img, uint32_t timeStamp);