From 11a0b40b6e2b873772e5c565748e9e0b209404c0 Mon Sep 17 00:00:00 2001
From: He Junyan <junyan.he@intel.com>
Date: Tue, 13 Aug 2024 22:41:00 +0800
Subject: [PATCH] va: deinterlace: Push the forgotten leading frames if forward
 reference > 0

The current code forgets to push the first several frames if the forward
reference > 0. They are just cached in history array and will never be
deinterlaced and pushed.
For the first several frames, even the forward reference frames are not
enough, we still need to deinterlace them as normal and push them after that.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7348>
---
 .../gst-plugins-bad/sys/va/gstvadeinterlace.c | 29 ++++++++++++-------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/subprojects/gst-plugins-bad/sys/va/gstvadeinterlace.c b/subprojects/gst-plugins-bad/sys/va/gstvadeinterlace.c
index f7bef8a0cb..07323c033e 100644
--- a/subprojects/gst-plugins-bad/sys/va/gstvadeinterlace.c
+++ b/subprojects/gst-plugins-bad/sys/va/gstvadeinterlace.c
@@ -93,6 +93,7 @@ struct _GstVaDeinterlace
   VAProcDeinterlacingType method;
 
   guint num_backward_references;
+  guint num_forward_references;
 
   GstBuffer *history[8];
   gint hcount;
@@ -126,8 +127,10 @@ _reset_history (GstVaDeinterlace * self)
   gint i;
 
   for (i = 0; i < self->hcount; i++)
-    gst_buffer_unref (self->history[i]);
+    gst_clear_buffer (&self->history[i]);
+
   self->hcount = 0;
+  self->hcurr = -1;
 }
 
 static void
@@ -215,6 +218,8 @@ gst_va_deinterlace_submit_input_buffer (GstBaseTransform * trans,
 
   gst_buffer_unref (buf);
 
+  self->hcurr = MIN (self->hcount, self->num_forward_references);
+
   if (self->hcount < self->hdepth) {
     self->history[self->hcount++] = inbuf;
   } else {
@@ -224,8 +229,8 @@ gst_va_deinterlace_submit_input_buffer (GstBaseTransform * trans,
     self->history[i] = inbuf;
   }
 
-  if (self->history[self->hcurr])
-    self->curr_field = FIRST_FIELD;
+  g_assert (self->history[self->hcurr]);
+  self->curr_field = FIRST_FIELD;
 
   return ret;
 }
@@ -236,7 +241,6 @@ _build_filter (GstVaDeinterlace * self)
   GstVaBaseTransform *btrans = GST_VA_BASE_TRANSFORM (self);
   guint i, num_caps;
   VAProcFilterCapDeinterlacing *caps;
-  guint32 num_forward_references;
 
   caps = gst_va_filter_get_filter_caps (btrans->filter,
       VAProcFilterDeinterlacing, &num_caps);
@@ -248,16 +252,18 @@ _build_filter (GstVaDeinterlace * self)
       continue;
 
     if (gst_va_filter_add_deinterlace_buffer (btrans->filter, self->method,
-            &num_forward_references, &self->num_backward_references)) {
-      self->hdepth = num_forward_references + self->num_backward_references + 1;
+            &self->num_forward_references, &self->num_backward_references)) {
+      self->hdepth =
+          self->num_forward_references + self->num_backward_references + 1;
       if (self->hdepth > 8) {
         GST_ELEMENT_ERROR (self, STREAM, FAILED,
             ("Pipeline requires too many references: (%u forward, %u backward)",
-                num_forward_references, self->num_backward_references), (NULL));
+                self->num_forward_references, self->num_backward_references),
+            (NULL));
       }
       GST_INFO_OBJECT (self, "References for method: %u forward / %u backward",
-          num_forward_references, self->num_backward_references);
-      self->hcurr = num_forward_references;
+          self->num_forward_references, self->num_backward_references);
+      self->hcurr = -1;
       return;
     }
   }
@@ -454,6 +460,8 @@ gst_va_deinterlace_generate_output (GstBaseTransform * trans,
 
   *outbuf = NULL;
 
+  g_assert (self->hcurr >= 0 && self->hcurr <= self->num_forward_references);
+
   if (self->curr_field == FINISHED)
     return GST_FLOW_OK;
 
@@ -461,7 +469,8 @@ gst_va_deinterlace_generate_output (GstBaseTransform * trans,
   if (!inbuf)
     return GST_FLOW_OK;
 
-  if (!self->history[self->hdepth - 1])
+  g_assert (self->hcurr + self->num_backward_references <= self->hdepth - 1);
+  if (!self->history[self->hcurr + self->num_backward_references])
     return GST_FLOW_OK;
 
   ret = GST_BASE_TRANSFORM_CLASS (parent_class)->prepare_output_buffer (trans,