fix qsv watermark alpha (#1239)

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Limit `HLS Direct` streams to realtime speed
 - Fix `Reset Playout` button to use worker thread instead of UI thread
   - This fixes potential UI hangs and database concurrency bugs
+- Maintain watermark alpha channel (built-in transparency) using QSV acceleration
 
 ### Changed
 - Remove duplicate items from smart collections before scheduling

ErsatzTV.FFmpeg/Pipeline/QsvPipelineBuilder.cs

@@ -411,11 +411,7 @@ public class QsvPipelineBuilder : SoftwarePipelineBuilder
                 watermark.FilterSteps.Add(new WatermarkOpacityFilter(watermark.DesiredState));
             }
 
-            IPixelFormat pixelFormat = context.Is10BitOutput
-                ? new PixelFormatNv12(FFmpegFormat.P010LE)
-                : new PixelFormatNv12(FFmpegFormat.YUVA420P);
-
-            watermark.FilterSteps.Add(new PixelFormatFilter(pixelFormat));
+            watermark.FilterSteps.Add(new PixelFormatFilter(new PixelFormatYuva420P()));
 
             foreach (List<WatermarkFadePoint> fadePoints in watermark.DesiredState.MaybeFadePoints)
             {