Bug 1843786 - webrtc: Implement Pipewire camera rotation support, r=webrtc-reviewers,pehrsons,@webrtc-reviewers

Support the Pipewire videotransform meta via the already existing shared
infrastructure. This is needed for mobile devices which often have a 90
degree rotated camera - which is likely the reason there is already
support in the shared code paths.

Upstream commit: dc4c019c62abefc09e4903abea44bc36f3427452

Differential Revision: https://phabricator.services.mozilla.com/D183652

third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.cc

@@ -278,6 +278,10 @@ void VideoCaptureModulePipeWire::OnFormatChanged(const struct spa_pod* format) {
       &builder, SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta, SPA_PARAM_META_type,
       SPA_POD_Id(SPA_META_Header), SPA_PARAM_META_size,
       SPA_POD_Int(sizeof(struct spa_meta_header)))));
+  params.push_back(reinterpret_cast<spa_pod*>(spa_pod_builder_add_object(
+      &builder, SPA_TYPE_OBJECT_ParamMeta, SPA_PARAM_Meta, SPA_PARAM_META_type,
+      SPA_POD_Id(SPA_META_VideoTransform), SPA_PARAM_META_size,
+      SPA_POD_Int(sizeof(struct spa_meta_videotransform)))));
   pw_stream_update_params(stream_, params.data(), params.size());
 }
 
@@ -315,12 +319,36 @@ void VideoCaptureModulePipeWire::OnStreamProcess(void* data) {
   that->ProcessBuffers();
 }
 
+static VideoRotation VideorotationFromPipeWireTransform(uint32_t transform) {
+  switch (transform) {
+    case SPA_META_TRANSFORMATION_90:
+      return kVideoRotation_90;
+    case SPA_META_TRANSFORMATION_180:
+      return kVideoRotation_180;
+    case SPA_META_TRANSFORMATION_270:
+      return kVideoRotation_270;
+    default:
+      return kVideoRotation_0;
+  }
+}
+
 void VideoCaptureModulePipeWire::ProcessBuffers() {
   while (pw_buffer* buffer = pw_stream_dequeue_buffer(stream_)) {
     struct spa_meta_header* h;
     h = static_cast<struct spa_meta_header*>(
         spa_buffer_find_meta_data(buffer->buffer, SPA_META_Header, sizeof(*h)));
 
+    struct spa_meta_videotransform* videotransform;
+    videotransform =
+        static_cast<struct spa_meta_videotransform*>(spa_buffer_find_meta_data(
+            buffer->buffer, SPA_META_VideoTransform, sizeof(*videotransform)));
+    if (videotransform) {
+      VideoRotation rotation =
+          VideorotationFromPipeWireTransform(videotransform->transform);
+      SetCaptureRotation(rotation);
+      SetApplyRotation(rotation != kVideoRotation_0);
+    }
+
     if (h->flags & SPA_META_HEADER_FLAG_CORRUPTED) {
       RTC_LOG(LS_INFO) << "Dropping corruped frame.";
     } else {

third_party/libwebrtc/moz-patch-stack/dc4c019c62.no-op-cherry-pick-msg

@@ -0,0 +1 @@
+We cherry-picked this in bug 1843786