vtdec: optimize renegotiation

::negotiate can be called several times before the CAPS event is sent downstream
so use the currently configured output state caps instead of the pad current
caps when deciding whether to recreate the VTSession or not.

This leads to creating/destroying less VTSessions which makes renegotiation more
reliable especially when using hw decoding.

diff --git a/sys/applemedia/vtdec.c b/sys/applemedia/vtdec.c
index cf736b2..7f96bd9 100644 (file)
--- a/sys/applemedia/vtdec.c
+++ b/sys/applemedia/vtdec.c
@@ -245,6 +245,12 @@ gst_vtdec_negotiate (GstVideoDecoder * decoder)
   if (features)
     features = gst_caps_features_copy (features);
 
+  output_state = gst_video_decoder_get_output_state (GST_VIDEO_DECODER (vtdec));
+  if (output_state) {
+    prevcaps = gst_caps_ref (output_state->caps);
+    gst_video_codec_state_unref (output_state);
+  }
+
   output_state = gst_video_decoder_set_output_state (GST_VIDEO_DECODER (vtdec),
       format, vtdec->video_info.width, vtdec->video_info.height,
       vtdec->input_state);
@@ -265,10 +271,10 @@ gst_vtdec_negotiate (GstVideoDecoder * decoder)
   }
   gst_caps_unref (caps);
 
-  prevcaps = gst_pad_get_current_caps (decoder->srcpad);
   if (!prevcaps || !gst_caps_is_equal (prevcaps, output_state->caps)) {
-    GST_INFO_OBJECT (vtdec, "negotiated output format %" GST_PTR_FORMAT,
-        output_state->caps);
+    GST_INFO_OBJECT (vtdec,
+        "negotiated output format %" GST_PTR_FORMAT " previous %"
+        GST_PTR_FORMAT, output_state->caps, prevcaps);
 
     if (vtdec->session) {
       gst_vtdec_push_frames_if_needed (vtdec, TRUE, FALSE);