DXVA2: adjust memory limit for 4K decoding from 3000 MB to 2960 MB

Change fallback strategy to limit decoder surfaces to 16 instead of exit

xbmc/cores/VideoPlayer/DVDCodecs/Video/DXVA.cpp

@@ -10,6 +10,8 @@
 // which we don't use here
 #define FF_API_OLD_SAMPLE_FMT 0
 
+#define LIMIT_VIDEO_MEMORY_4K 2960ull
+
 #include "DXVA.h"
 
 #include "ServiceBroker.h"
@@ -1221,12 +1223,12 @@ bool CDecoder::Open(AVCodecContext* avctx, AVCodecContext* mainctx, enum AVPixel
  }
 
  // Check if available video memory is sufficient for 4K decoding (is need ~3000 MB)
- if (avctx->width >= 3840 && m_refs > 16 && videoMem < (3000ull * MB))
+ if (avctx->width >= 3840 && m_refs > 16 && videoMem < (LIMIT_VIDEO_MEMORY_4K * MB))
  {
  CLog::LogF(LOGWARNING,
  "Current available video memory ({} MB) is insufficient 4K video decoding (DXVA2) "
- "using {} surfaces. Fallback to SW decode.", videoMem / MB, m_refs);
- return false;
+ "using {} surfaces. Decoder surfaces has been limited to 16.", videoMem / MB, m_refs);
+ m_refs = 16;
  }
 
  /* On the Xbox 1/S with limited memory we have to