[GStreamer][LibWebRTC] Keep size in decoder caps synchronized with encoded image dimensions

https://bugs.webkit.org/show_bug.cgi?id=277630

Reviewed by Xabier Rodriguez-Calvar.

Update the caps of the decoder when the encoded image dimensions change. Those caps are also used by
GStreamerVideoFrameLibWebRTC and later by LibWebRTCStatsCollector. Without this change, resolution
in inbound-rtp statistics is never updated.

Based on patch from Jacek Manko <jacek.manko@consult.red>.
#1380

* Source/WebCore/platform/mediastream/libwebrtc/gstreamer/GStreamerVideoDecoderFactory.cpp:
(WebCore::GStreamerWebRTCVideoDecoder::updateCapsFromImageSize):
(WebCore::GStreamerWebRTCVideoDecoder::GetCapsForFrame): Deleted.

Canonical link: https://commits.webkit.org/282115@main

Author: philn

Source/WebCore/platform/mediastream/libwebrtc/gstreamer/GStreamerVideoDecoderFactory.cpp

@@ -102,8 +102,7 @@ class GStreamerWebRTCVideoDecoder : public webrtc::VideoDecoder {
         auto capsfilter = CreateFilter();
         auto decoder = makeElement("decodebin");
 
-        m_width = codecSettings.max_render_resolution().Width();
-        m_height = codecSettings.max_render_resolution().Height();
+        updateCapsFromImageSize(codecSettings.max_render_resolution().Width(), codecSettings.max_render_resolution().Height());
 
         m_pipeline = makeElement("pipeline");
         connectSimpleBusMessageCallback(m_pipeline.get());
@@ -212,13 +211,22 @@ class GStreamerWebRTCVideoDecoder : public webrtc::VideoDecoder {
             return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
         }
 
+        if (inputImage._encodedWidth && inputImage._encodedHeight)
+            updateCapsFromImageSize(inputImage._encodedWidth, inputImage._encodedHeight);
+
+        if (UNLIKELY(!m_caps)) {
+            GST_ERROR("Encoded image caps not set");
+            ASSERT_NOT_REACHED();
+            return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
+        }
+
         // FIXME: Use a GstBufferPool.
         GST_TRACE_OBJECT(pipeline(), "Pushing encoded image with RTP timestamp %u", inputImage.RtpTimestamp());
         auto buffer = adoptGRef(gstBufferNewWrappedFast(fastMemDup(inputImage.data(), inputImage.size()), inputImage.size()));
 
         gst_buffer_add_reference_timestamp_meta(buffer.get(), m_rtpTimestampCaps.get(), inputImage.RtpTimestamp(), GST_CLOCK_TIME_NONE);
 
-        auto sample = adoptGRef(gst_sample_new(buffer.get(), GetCapsForFrame(inputImage), nullptr, nullptr));
+        auto sample = adoptGRef(gst_sample_new(buffer.get(), m_caps.get(), nullptr, nullptr));
         switch (gst_app_src_push_sample(GST_APP_SRC(m_src), sample.get())) {
         case GST_FLOW_OK:
             break;
@@ -247,16 +255,14 @@ class GStreamerWebRTCVideoDecoder : public webrtc::VideoDecoder {
         return WEBRTC_VIDEO_CODEC_OK;
     }
 
-    virtual GstCaps* GetCapsForFrame(const webrtc::EncodedImage& image)
+    virtual void updateCapsFromImageSize(int width, int height)
     {
-        if (!m_caps) {
-            m_caps = adoptGRef(gst_caps_new_simple(Caps(),
-                "width", G_TYPE_INT, image._encodedWidth ? image._encodedWidth : m_width,
-                "height", G_TYPE_INT, image._encodedHeight ? image._encodedHeight : m_height,
-                nullptr));
-        }
+        if (m_width == width && m_height == height)
+            return;
 
-        return m_caps.get();
+        m_width = width;
+        m_height = height;
+        m_caps = adoptGRef(gst_caps_new_simple(Caps(), "width", G_TYPE_INT, width, "height", G_TYPE_INT, height, nullptr));
     }
 
     void AddDecoderIfSupported(std::vector<webrtc::SdpVideoFormat>& codecList)
@@ -289,8 +295,8 @@ class GStreamerWebRTCVideoDecoder : public webrtc::VideoDecoder {
 
 protected:
     GRefPtr<GstCaps> m_caps;
-    gint m_width;
-    gint m_height;
+    int m_width;
+    int m_height;
     bool m_requireParse = false;
     bool m_needsKeyframe;
 
@@ -323,17 +329,15 @@ class H264Decoder : public GStreamerWebRTCVideoDecoder {
         return GStreamerWebRTCVideoDecoder::Configure(codecSettings);
     }
 
-    GstCaps* GetCapsForFrame(const webrtc::EncodedImage& image) final
+    void updateCapsFromImageSize(int width, int height) final
     {
-        if (!m_caps) {
-            m_caps = adoptGRef(gst_caps_new_simple(Caps(),
-                "width", G_TYPE_INT, image._encodedWidth ? image._encodedWidth : m_width,
-                "height", G_TYPE_INT, image._encodedHeight ? image._encodedHeight : m_height,
-                "alignment", G_TYPE_STRING, "au",
-                nullptr));
-        }
+        if (m_width == width && m_height == height)
+            return;
 
-        return m_caps.get();
+        m_width = width;
+        m_height = height;
+        m_caps = adoptGRef(gst_caps_new_simple(Caps(), "width", G_TYPE_INT, width, "height", G_TYPE_INT, height,
+            "alignment", G_TYPE_STRING, "au", nullptr));
     }
     const gchar* Caps() final { return "video/x-h264"; }
     const gchar* Name() final { return cricket::kH264CodecName; }