[AV1e/lib] Refine AV1 DPB refresh (#6346)

If DPB size is smaller than 8, the location beyond valid DPB slots will only be refreshed by Key frame.
This will make key frame always cached in decoder, and this commit refines it by refreshing all these untouched slots for each ref frame.

Co-authored-by: Xue, Maxim <[email protected]>

_studio/mfx_lib/encode_hw/av1/agnostic/base/av1ehw_base_general.cpp

@@ -2251,7 +2251,7 @@ inline void SetTaskDPBRefresh(
     auto& refreshRefFrames = task.RefreshFrameFlags;
 
     if (IsI(task.FrameType))
-        std::fill(refreshRefFrames.begin(), refreshRefFrames.end(), static_cast<mfxU8>(1));
+        std::fill(refreshRefFrames.begin(), refreshRefFrames.end(), mfxU8(1));
     else if (IsRef(task.FrameType))
     {
         // At first find all rejected LTRs to refresh them with current frame
@@ -2286,6 +2286,10 @@ inline void SetTaskDPBRefresh(
         // If this frame is not put into DPB, it will not be ref-frame
         if (std::find(refreshRefFrames.begin(), refreshRefFrames.end(), 1) == refreshRefFrames.end())
             task.FrameType &= ~MFX_FRAMETYPE_REF;
+        else
+        {
+            std::fill(refreshRefFrames.begin() + task.DPB.size(), refreshRefFrames.end(), mfxU8(1));
+        }
     }
 
 }