codecs: mpeg2decoder: Use tsg framerate for latency.

Latency setting relies on src pad caps, but they aren't set when the
function is called, and latency is never updated.

In order to fix it, this patch uses TSG framerate first, and if it's
not set yet, sinkpad caps are used to get the framerate.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2514>

1 files changed, 16 insertions, 10 deletions

diff --git a/gst-libs/gst/codecs/gstmpeg2decoder.c b/gst-libs/gst/codecs/gstmpeg2decoder.c
index d9c275349..ae0e331e6 100644
--- a/gst-libs/gst/codecs/gstmpeg2decoder.c
+++ b/gst-libs/gst/codecs/gstmpeg2decoder.c
@@ -404,21 +404,27 @@ gst_mpeg2_decoder_set_latency (GstMpeg2Decoder * decoder)
 {
   GstCaps *caps;
   GstClockTime min, max;
+  GstMpeg2DecoderPrivate *priv = decoder->priv;
   GstStructure *structure;
   gint fps_d = 1, fps_n = 0;
 
-  caps = gst_pad_get_current_caps (GST_VIDEO_DECODER_SRC_PAD (decoder));
-  if (!caps)
-    return;
-
-  structure = gst_caps_get_structure (caps, 0);
-  if (gst_structure_get_fraction (structure, "framerate", &fps_n, &fps_d)) {
-    if (fps_n == 0) {
-      /* variable framerate: see if we have a max-framerate */
-      gst_structure_get_fraction (structure, "max-framerate", &fps_n, &fps_d);
+  if (priv->tsg.fps_d > 0 && priv->tsg.fps_n > 0) {
+    fps_n = priv->tsg.fps_n;
+    fps_d = priv->tsg.fps_d;
+  } else {
+    caps = gst_pad_get_current_caps (GST_VIDEO_DECODER_SINK_PAD (decoder));
+    if (caps) {
+      structure = gst_caps_get_structure (caps, 0);
+      if (gst_structure_get_fraction (structure, "framerate", &fps_n, &fps_d)) {
+        if (fps_n == 0) {
+          /* variable framerate: see if we have a max-framerate */
+          gst_structure_get_fraction (structure, "max-framerate", &fps_n,
+              &fps_d);
+        }
+      }
+      gst_caps_unref (caps);
     }
   }
-  gst_caps_unref (caps);
 
   /* if no fps or variable, then 25/1 */
   if (fps_n == 0) {