Bug 1726617 - p1: use video encoder fallback wrapper in WebRTC. r=pehrsons

Differential Revision: https://phabricator.services.mozilla.com/D126975

dom/media/webrtc/libwebrtcglue/WebrtcVideoCodecFactory.cpp

@@ -13,6 +13,7 @@
 // libwebrtc includes
 #include "api/rtp_headers.h"
 #include "api/video_codecs/video_codec.h"
+#include "api/video_codecs/video_encoder_software_fallback_wrapper.h"
 #include "media/engine/encoder_simulcast_proxy.h"
 #include "modules/video_coding/codecs/vp8/include/vp8.h"
 #include "modules/video_coding/codecs/vp9/include/vp9.h"
@@ -92,13 +93,15 @@ std::unique_ptr<webrtc::VideoEncoder>
 WebrtcVideoEncoderFactory::InternalFactory::CreateVideoEncoder(
     const webrtc::SdpVideoFormat& aFormat) {
   MOZ_ASSERT(Supports(aFormat));
-  std::unique_ptr<webrtc::VideoEncoder> encoder;
 
-  encoder.reset(MediaDataCodec::CreateEncoder(aFormat));
-  if (encoder) {
-    return encoder;
+  std::unique_ptr<webrtc::VideoEncoder> platformEncoder;
+  platformEncoder.reset(MediaDataCodec::CreateEncoder(aFormat));
+  const bool fallback = StaticPrefs::media_webrtc_software_encoder_fallback();
+  if (!fallback && platformEncoder) {
+    return platformEncoder;
   }
 
+  std::unique_ptr<webrtc::VideoEncoder> encoder;
   switch (webrtc::PayloadStringToCodecType(aFormat.name)) {
     case webrtc::VideoCodecType::kVideoCodecH264: {
       // get an external encoder
@@ -121,6 +124,13 @@ WebrtcVideoEncoderFactory::InternalFactory::CreateVideoEncoder(
     default:
       break;
   }
+  if (fallback && encoder && platformEncoder) {
+    return webrtc::CreateVideoEncoderSoftwareFallbackWrapper(
+        std::move(encoder), std::move(platformEncoder), false);
+  }
+  if (platformEncoder) {
+    return platformEncoder;
+  }
   return encoder;
 }
 

modules/libpref/init/StaticPrefList.yaml

@@ -3821,7 +3821,7 @@
   mirror: always
 
 # Points in the native bounds geometry are required to be quantized
-# sufficiently to prevent fingerprinting. The WebXR spec suggests 
+# sufficiently to prevent fingerprinting. The WebXR spec suggests
 # quantizing to the nearest 5 centimeters.
 - name: dom.vr.webxr.quantization
   type: AtomicFloat
@@ -8935,6 +8935,15 @@
 #endif
   mirror: always
 
+- name: media.webrtc.software_encoder.fallback
+  type: RelaxedAtomicBool
+#if defined(MOZ_WIDGET_ANDROID) || defined(NIGHTLY_BUILD)
+  value: true
+#else
+  value: false
+#endif
+  mirror: always
+
 - name: media.block-autoplay-until-in-foreground
   type: bool
 #if !defined(MOZ_WIDGET_ANDROID)