decoder: h264: factor out DPB pruning for MVC.

Factor out the removal process of unused inter-view only reference
pictures from the DPB, prior to the possible insertion of the current
picture.

Ideally, the compiler could still opt for generating two loops. But
at least, the code is now clearer for maintenance.

diff --git a/gst-libs/gst/vaapi/gstvaapidecoder_h264.c b/gst-libs/gst/vaapi/gstvaapidecoder_h264.c
index 5cea099..d8219e8 100644 (file)
--- a/gst-libs/gst/vaapi/gstvaapidecoder_h264.c
+++ b/gst-libs/gst/vaapi/gstvaapidecoder_h264.c
@@ -873,31 +873,21 @@ static void
 dpb_prune_mvc(GstVaapiDecoderH264 *decoder, GstVaapiPictureH264 *picture)
 {
     GstVaapiDecoderH264Private * const priv = &decoder->priv;
+    const gboolean is_last_picture = /* in the access unit */
+        GST_VAAPI_PICTURE_FLAG_IS_SET(picture, GST_VAAPI_PICTURE_FLAG_AU_END);
     guint i;
 
     // Remove all unused inter-view only reference components of the current AU
-    if (GST_VAAPI_PICTURE_FLAG_IS_SET(picture, GST_VAAPI_PICTURE_FLAG_AU_END)) {
-        i = 0;
-        while (i < priv->dpb_count) {
-            GstVaapiFrameStore * const fs = priv->dpb[i];
-            if (fs->view_id != picture->base.view_id &&
-                !fs->output_needed && !gst_vaapi_frame_store_has_reference(fs))
-                dpb_remove_index(decoder, i);
-            else
-                i++;
-        }
-    }
-    else {
-        i = 0;
-        while (i < priv->dpb_count) {
-            GstVaapiFrameStore * const fs = priv->dpb[i];
-            if (fs->view_id != picture->base.view_id &&
-                !fs->output_needed && !gst_vaapi_frame_store_has_reference(fs) &&
-                !is_inter_view_reference_for_next_frames(decoder, fs))
-                dpb_remove_index(decoder, i);
-            else
-                i++;
-        }
+    i = 0;
+    while (i < priv->dpb_count) {
+        GstVaapiFrameStore * const fs = priv->dpb[i];
+        if (fs->view_id != picture->base.view_id &&
+            !fs->output_needed && !gst_vaapi_frame_store_has_reference(fs) &&
+            (is_last_picture ||
+             !is_inter_view_reference_for_next_frames(decoder, fs)))
+            dpb_remove_index(decoder, i);
+        else
+            i++;
     }
 }