[GStreamer] Another crash under gst_element_add_pad

https://bugs.webkit.org/show_bug.cgi?id=225765

Patch by Philippe Normand <pnormand@igalia.com> on 2021-06-15
Reviewed by Adrian Perez de Castro.

Decodebin3 in GStreamer <= 1.16 does not respect user-supplied select-stream events. So we
need to relax the release assert for these versions. This bug was fixed in:
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/commit/b41b87522f59355bb21c001e9e2df96dc6956928

* platform/graphics/gstreamer/ImageDecoderGStreamer.cpp:
(WebCore::ImageDecoderGStreamer::InnerDecoder::connectDecoderPad):

Canonical link: https://commits.webkit.org/238834@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@278892 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,17 @@
+2021-06-15  Philippe Normand  <pnormand@igalia.com>
+
+        [GStreamer] Another crash under gst_element_add_pad
+        https://bugs.webkit.org/show_bug.cgi?id=225765
+
+        Reviewed by Adrian Perez de Castro.
+
+        Decodebin3 in GStreamer <= 1.16 does not respect user-supplied select-stream events. So we
+        need to relax the release assert for these versions. This bug was fixed in:
+        https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/commit/b41b87522f59355bb21c001e9e2df96dc6956928
+
+        * platform/graphics/gstreamer/ImageDecoderGStreamer.cpp:
+        (WebCore::ImageDecoderGStreamer::InnerDecoder::connectDecoderPad):
+
 2021-06-06  Darin Adler  <darin@apple.com>
 
         Delete some recently-obsoleted files

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

@@ -238,7 +238,15 @@ void ImageDecoderGStreamer::InnerDecoder::connectDecoderPad(GstPad* pad)
 {
     auto padCaps = adoptGRef(gst_pad_query_caps(pad, nullptr));
     GST_DEBUG_OBJECT(m_pipeline.get(), "New decodebin pad %" GST_PTR_FORMAT " caps: %" GST_PTR_FORMAT, pad, padCaps.get());
-    RELEASE_ASSERT(doCapsHaveType(padCaps.get(), "video"));
+
+    // Decodebin3 in GStreamer <= 1.16 does not respect user-supplied select-stream events. So we
+    // need to relax the release assert for these versions. This bug was fixed in:
+    // https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/commit/b41b87522f59355bb21c001e9e2df96dc6956928
+    bool isVideo = doCapsHaveType(padCaps.get(), "video");
+    if (webkitGstCheckVersion(1, 18, 0))
+        RELEASE_ASSERT(isVideo);
+    else if (!isVideo)
+        return;
 
     GstElement* sink = makeGStreamerElement("appsink", nullptr);
     static GstAppSinkCallbacks callbacks = {