codecs: Fix the H265 poc out of order warning.

We always get a warning such as:
h265decoder gsth265decoder.c:1432:gst_h265_decoder_do_output_picture: \
<vah265dec0> Outputting out of order 255 -> 0, likely a broken stream
in H265 decoder.

The problem is caused because we fail to reset the last_output_poc when
we get IDR and BLA. The incoming IDR and BLA frame already bump all the
frames in the DPB, but we forget to reset the last_output_poc, which
make the POC out of order and generate the warning all the time.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2294>

1 files changed, 8 insertions, 0 deletions

diff --git a/gst-libs/gst/codecs/gsth265decoder.c b/gst-libs/gst/codecs/gsth265decoder.c
index 21f44dc48..dc8240fc5 100644
--- a/gst-libs/gst/codecs/gsth265decoder.c
+++ b/gst-libs/gst/codecs/gsth265decoder.c
@@ -1521,6 +1521,14 @@ gst_h265_decoder_dpb_init (GstH265Decoder * self, const GstH265Slice * slice,
       gst_h265_dpb_delete_unused (priv->dpb);
       while ((to_output = gst_h265_dpb_bump (priv->dpb, FALSE)) != NULL)
         gst_h265_decoder_do_output_picture (self, to_output);
+
+      if (gst_h265_dpb_get_size (priv->dpb) > 0) {
+        GST_WARNING_OBJECT (self, "IDR or BLA frame failed to clear the dpb, "
+            "there are still %d pictures in the dpb, last output poc is %d",
+            gst_h265_dpb_get_size (priv->dpb), priv->last_output_poc);
+      } else {
+        priv->last_output_poc = 0;
+      }
     }
   } else {
     gst_h265_dpb_delete_unused (priv->dpb);