Mesa (master): st/va: Fix forward/backward referencing for deinterlacing

[Christian König]

Module: Mesa
Branch: master
Commit: 0798fddb5000f2b1edffc693ec65236a680ce61f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0798fddb5000f2b1edffc693ec65236a680ce61f

Author: Mark Thompson <sw at jkqxz.net>
Date:   Wed Mar  1 20:07:09 2017 +0000

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 at jkqxz.net>
Reviewed-by: Christian König <christian.koenig at amd.com>

---

 src/gallium/state_trackers/va/postproc.c | 10 +++++-----
 src/gallium/state_trackers/va/surface.c  |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/gallium/state_trackers/va/postproc.c b/src/gallium/state_trackers/va/postproc.c
index 01e240f..fbec69a 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 0e1dbe0..b129e6c 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;
       }