Allow encoders to receive preferred pixel formats from native buffers

Adds a field to EncoderInfo called preferred_pixel_formats which a
software encoder populates with the pixel formats it supports. When a
kNative frame is received for encoding, the VideoStreamEncoder will
first try to get a frame that is accessible by the software encoder in
that pixel format from the kNative frame. If this fails it will fallback
to converting the frame using ToI420.

This minimizes the number of conversions made in the case that the
encoder supports the pixel format of the native buffer or where
conversion can be accelerated. For example, in Chromium, the capturer can
emit an NV12 frame, which can be consumed by libvpx which supports NV12.

Testing: Tested in Chrome with media::VideoFrame adapters.

Bug: webrtc:11977
Change-Id: I9becc4100136b0c0128f4fa06dedf9ee4dc62f37
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/187121
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Markus Handell <handellm@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@google.com>
Cr-Commit-Position: refs/heads/master@{#32353}

modules/video_coding/codecs/av1/libaom_av1_encoder.cc

@@ -603,6 +603,7 @@ VideoEncoder::EncoderInfo LibaomAv1Encoder::GetEncoderInfo() const {
   info.has_trusted_rate_controller = true;
   info.is_hardware_accelerated = false;
   info.scaling_settings = VideoEncoder::ScalingSettings(kMinQindex, kMaxQindex);
+  info.preferred_pixel_formats = {VideoFrameBuffer::Type::kI420};
   return info;
 }
 

modules/video_coding/codecs/h264/h264_encoder_impl.cc

@@ -615,6 +615,7 @@ VideoEncoder::EncoderInfo H264EncoderImpl::GetEncoderInfo() const {
   info.is_hardware_accelerated = false;
   info.has_internal_source = false;
   info.supports_simulcast = true;
+  info.preferred_pixel_formats = {VideoFrameBuffer::Type::kI420};
   return info;
 }
 

modules/video_coding/codecs/vp8/libvpx_vp8_encoder.cc

@@ -1244,6 +1244,8 @@ VideoEncoder::EncoderInfo LibvpxVp8Encoder::GetEncoderInfo() const {
     info.scaling_settings.min_pixels_per_frame =
         rate_control_settings_.LibvpxVp8MinPixels().value();
   }
+  info.preferred_pixel_formats = {VideoFrameBuffer::Type::kI420,
+                                  VideoFrameBuffer::Type::kNV12};
 
   if (inited_) {
     // |encoder_idx| is libvpx index where 0 is highest resolution.

modules/video_coding/codecs/vp8/test/vp8_impl_unittest.cc

@@ -604,6 +604,9 @@ TEST(LibvpxVp8EncoderTest, GetEncoderInfoReturnsStaticInformation) {
   EXPECT_TRUE(info.supports_simulcast);
   EXPECT_EQ(info.implementation_name, "libvpx");
   EXPECT_EQ(info.requested_resolution_alignment, 1);
+  EXPECT_THAT(info.preferred_pixel_formats,
+              testing::UnorderedElementsAre(VideoFrameBuffer::Type::kNV12,
+                                            VideoFrameBuffer::Type::kI420));
 }
 
 TEST(LibvpxVp8EncoderTest, RequestedResolutionAlignmentFromFieldTrial) {

modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc

@@ -1337,6 +1337,12 @@ TEST_F(TestVp9Impl, ScalabilityStructureIsAvailableInFlexibleMode) {
   EXPECT_TRUE(codec_specific_info.codecSpecific.VP9.ss_data_available);
 }
 
+TEST_F(TestVp9Impl, Profile0PreferredPixelFormats) {
+  EXPECT_THAT(encoder_->GetEncoderInfo().preferred_pixel_formats,
+              testing::UnorderedElementsAre(VideoFrameBuffer::Type::kNV12,
+                                            VideoFrameBuffer::Type::kI420));
+}
+
 TEST_F(TestVp9Impl, EncoderInfoFpsAllocation) {
   const uint8_t kNumSpatialLayers = 3;
   const uint8_t kNumTemporalLayers = 3;

modules/video_coding/codecs/vp9/vp9_impl.cc

@@ -1656,6 +1656,10 @@ VideoEncoder::EncoderInfo VP9EncoderImpl::GetEncoderInfo() const {
                                          (sl_fps_fraction / decimator)));
       }
     }
+    if (profile_ == VP9Profile::kProfile0) {
+      info.preferred_pixel_formats = {VideoFrameBuffer::Type::kI420,
+                                      VideoFrameBuffer::Type::kNV12};
+    }
   }
   return info;
 }