From: Mark Thompson <sw@jkqxz.net>
Date: Wed, 1 Mar 2017 20:07:09 +0000 (+0000)
Subject: st/va: Fix forward/backward referencing for deinterlacing
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0798fddb5000f2b1edffc693ec65236a680ce61f;p=mesa.git

st/va: Fix forward/backward referencing for deinterlacing

The VAAPI documentation is not very clear here, but the intent
appears to be that a forward reference is forward from a frame in the
past, not forward to a frame in the future (that is, forward as in
forward prediction, not as in a forward reference in source code).
This interpretation is derived from other implementations, in
particular the i965 driver and the gstreamer client.

In order to match those other implementations, this patch swaps the
meaning of forward and backward references as they currently appear
for motion-adaptive deinterlacing.

Signed-off-by: Mark Thompson <sw@jkqxz.net>
Reviewed-by: Christian König <christian.koenig@amd.com>
---

diff --git a/src/gallium/state_trackers/va/postproc.c b/src/gallium/state_trackers/va/postproc.c
index 01e240f0167..fbec69aec35 100644
--- a/src/gallium/state_trackers/va/postproc.c
+++ b/src/gallium/state_trackers/va/postproc.c
@@ -184,13 +184,13 @@ vlVaApplyDeint(vlVaDriver *drv, vlVaContext *context,
 {
    vlVaSurface *prevprev, *prev, *next;
 
-   if (param->num_forward_references < 1 ||
-       param->num_backward_references < 2)
+   if (param->num_forward_references < 2 ||
+       param->num_backward_references < 1)
       return current;
 
-   prevprev = handle_table_get(drv->htab, param->backward_references[1]);
-   prev = handle_table_get(drv->htab, param->backward_references[0]);
-   next = handle_table_get(drv->htab, param->forward_references[0]);
+   prevprev = handle_table_get(drv->htab, param->forward_references[1]);
+   prev = handle_table_get(drv->htab, param->forward_references[0]);
+   next = handle_table_get(drv->htab, param->backward_references[0]);
 
    if (!prevprev || !prev || !next)
       return current;
diff --git a/src/gallium/state_trackers/va/surface.c b/src/gallium/state_trackers/va/surface.c
index 0e1dbe0b109..b129e6c74f4 100644
--- a/src/gallium/state_trackers/va/surface.c
+++ b/src/gallium/state_trackers/va/surface.c
@@ -845,8 +845,8 @@ vlVaQueryVideoProcPipelineCaps(VADriverContextP ctx, VAContextID context,
       case VAProcFilterDeinterlacing: {
          VAProcFilterParameterBufferDeinterlacing *deint = buf->data;
          if (deint->algorithm == VAProcDeinterlacingMotionAdaptive) {
-            pipeline_cap->num_forward_references = 1;
-            pipeline_cap->num_backward_references = 2;
+            pipeline_cap->num_forward_references = 2;
+            pipeline_cap->num_backward_references = 1;
          }
          break;
       }