[WPE][Debug]: fast/mediastream/captureStream/canvas3d.html crashes wi…

…th error gst_sample_get_caps: assertion 'GST_IS_SAMPLE (sample)' failed

https://bugs.webkit.org/show_bug.cgi?id=259915

Reviewed by Carlos Garcia Campos.

Report video frame conversion errors and gracefully handle them in the player.

* Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp:
(WebCore::MediaPlayerPrivateGStreamer::videoFrameForCurrentTime):
* Source/WebCore/platform/graphics/gstreamer/VideoFrameGStreamer.cpp:
(WebCore::VideoFrameGStreamer::convert):

Canonical link: https://commits.webkit.org/266723@main

Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp

@@ -3873,6 +3873,9 @@ RefPtr<VideoFrame> MediaPlayerPrivateGStreamer::videoFrameForCurrentTime()
     auto* buffer = gst_sample_get_buffer(m_sample.get());
     auto frame = VideoFrameGStreamer::createWrappedSample(m_sample.get(), fromGstClockTime(GST_BUFFER_PTS(buffer)));
     auto convertedSample = frame->downloadSample(GST_VIDEO_FORMAT_BGRA);
+    if (!convertedSample)
+        return nullptr;
+
     auto size = getVideoResolutionFromCaps(gst_sample_get_caps(m_sample.get())).value_or(FloatSize { 0, 0 });
     return VideoFrameGStreamer::create(WTFMove(convertedSample), size);
 }

Source/WebCore/platform/graphics/gstreamer/VideoFrameGStreamer.cpp

@@ -466,25 +466,27 @@ GRefPtr<GstSample> VideoFrameGStreamer::resizedSample(const IntSize& destination
 GRefPtr<GstSample> VideoFrameGStreamer::convert(GstVideoFormat format, const IntSize& destinationSize)
 {
     auto* caps = gst_sample_get_caps(m_sample.get());
-
     const auto* structure = gst_caps_get_structure(caps, 0);
     int frameRateNumerator, frameRateDenominator;
     if (!gst_structure_get_fraction(structure, "framerate", &frameRateNumerator, &frameRateDenominator)) {
         frameRateNumerator = 1;
         frameRateDenominator = 1;
     }
 
-    GstVideoInfo inputInfo;
-    gst_video_info_from_caps(&inputInfo, caps);
-
     auto width = destinationSize.width();
     auto height = destinationSize.height();
-    auto outputCaps = adoptGRef(gst_caps_new_simple("video/x-raw", "format", G_TYPE_STRING, gst_video_format_to_string(format), "width", G_TYPE_INT, width, "height", G_TYPE_INT, height, "framerate", GST_TYPE_FRACTION, frameRateNumerator, frameRateDenominator, nullptr));
+    const char* formatName = gst_video_format_to_string(format);
+    auto outputCaps = adoptGRef(gst_caps_new_simple("video/x-raw", "format", G_TYPE_STRING, formatName, "width", G_TYPE_INT, width, "height", G_TYPE_INT, height, "framerate", GST_TYPE_FRACTION, frameRateNumerator, frameRateDenominator, nullptr));
 
     if (gst_caps_is_equal(caps, outputCaps.get()))
         return GRefPtr<GstSample>(m_sample);
 
-    return adoptGRef(gst_video_convert_sample(m_sample.get(), outputCaps.get(), GST_CLOCK_TIME_NONE, nullptr));
+    GUniqueOutPtr<GError> error;
+    auto convertedSample = adoptGRef(gst_video_convert_sample(m_sample.get(), outputCaps.get(), GST_CLOCK_TIME_NONE, &error.outPtr()));
+    if (!convertedSample)
+        GST_ERROR("Conversion to %s failed: %s", formatName, error->message);
+
+    return convertedSample;
 }
 
 GRefPtr<GstSample> VideoFrameGStreamer::downloadSample(std::optional<GstVideoFormat> destinationFormat)