codecs: av1decoder: Add the highest_spatial_layer field.

As SPEC says, when multi spatial layer exists, we should only output
one frame with the highest spatial id from each TU. We now store the
highest spatial layer information in the base class in order to let
the sub class handle different layers easily.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2382>

subprojects/gst-plugins-bad/gst-libs/gst/codecs/gstav1decoder.c

@@ -140,6 +140,8 @@ gst_av1_decoder_reset (GstAV1Decoder * self)
 {
   GstAV1DecoderPrivate *priv = self->priv;
 
+  self->highest_spatial_layer = 0;
+
   priv->max_width = 0;
   priv->max_height = 0;
   gst_clear_av1_picture (&priv->current_picture);
@@ -379,6 +381,13 @@ gst_av1_decoder_process_sequence (GstAV1Decoder * self, GstAV1OBU * obu)
     priv->preferred_output_delay = 0;
   }
 
+  if (priv->parser->state.operating_point_idc) {
+    self->highest_spatial_layer =
+        _floor_log2 (priv->parser->state.operating_point_idc >> 8);
+    GST_INFO_OBJECT (self, "set highest spatial layer to %d",
+        self->highest_spatial_layer);
+  }
+
   ret = klass->new_sequence (self, &seq_header,
       GST_AV1_TOTAL_REFS_PER_FRAME + priv->preferred_output_delay);
   if (ret != GST_FLOW_OK) {
@@ -475,6 +484,9 @@ gst_av1_decoder_decode_frame_header (GstAV1Decoder * self,
     picture->temporal_id = obu->header.obu_temporal_id;
     picture->spatial_id = obu->header.obu_spatial_id;
 
+    g_assert (picture->spatial_id <= self->highest_spatial_layer);
+    g_assert (self->highest_spatial_layer < GST_AV1_MAX_NUM_SPATIAL_LAYERS);
+
     if (!frame_header->show_frame && !frame_header->showable_frame)
       GST_VIDEO_CODEC_FRAME_FLAG_SET (priv->current_frame,
           GST_VIDEO_CODEC_FRAME_FLAG_DECODE_ONLY);
@@ -683,6 +695,15 @@ gst_av1_decoder_handle_frame (GstVideoDecoder * decoder,
     goto out;
   }
 
+  if (priv->current_picture->temporal_id > self->highest_spatial_layer) {
+    ret = GST_FLOW_ERROR;
+    GST_VIDEO_DECODER_ERROR (self, 1, STREAM, DECODE,
+        ("current picture temporal_id %d should not be higher than "
+            "highest spatial layer %d", priv->current_picture->temporal_id,
+            self->highest_spatial_layer), (NULL), ret);
+    goto out;
+  }
+
   if (!priv->current_picture->frame_hdr.show_existing_frame) {
     if (klass->end_picture) {
       ret = klass->end_picture (self, priv->current_picture);
@@ -704,9 +725,7 @@ out:
       /* Only output one frame with the highest spatial id from each TU
        * when there are multiple spatial layers.
        */
-      if (priv->parser->state.operating_point_idc &&
+      if (obu.header.obu_spatial_id < self->highest_spatial_layer) {
-          obu.header.obu_spatial_id <
-          _floor_log2 (priv->parser->state.operating_point_idc >> 8)) {
         gst_av1_picture_unref (priv->current_picture);
         gst_video_decoder_release_frame (decoder, frame);
       } else {

subprojects/gst-plugins-bad/gst-libs/gst/codecs/gstav1decoder.h

@@ -53,6 +53,7 @@ struct _GstAV1Decoder
 
   /*< protected >*/
   GstVideoCodecState * input_state;
+  guint highest_spatial_layer;
 
   /*< private >*/
   GstAV1DecoderPrivate *priv;