fix nvenc playback when color metadata changes mid-stream

CHANGELOG.md

@@ -55,7 +55,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Automatically kill playback troubleshooting ffmpeg process if it hasn't completed after two minutes
 - Fix playback of certain BT.2020 content
 - Use playlist item count when using a playlist as filler (instead of a fixed count of 1 for each playlist item)
-- NVIDIA: fix stream failure with certain content that should decode in hardware but falls back to software
+- NVIDIA:
+  - Fix stream failure with certain content that should decode in hardware but falls back to software
+  - Fix stream failure with content that changes color metadata mid-stream
 - Fix stream failure when configured fallback filler collection is empty
 - Fix high CPU when errors are displayed; errors will now work ahead before throttling to realtime, similar to primary content
 - Fix startup error caused by duplicate smart collection names (and no longer allow duplicate smart collection names)

ErsatzTV.FFmpeg/Pipeline/NvidiaPipelineBuilder.cs

@@ -364,6 +364,18 @@ public class NvidiaPipelineBuilder : SoftwarePipelineBuilder
                     desiredState.CroppedSize.IfNone(desiredState.PaddedSize)));
         }
 
+        // unknown color params can *change* during transcoding,
+        // which can cause ffmpeg to insert an autoscale filter that
+        // cannot accept hardware frames.
+        // this filter isn't actually needed (the encoder accepts the frames just fine) so disable it
+        if (ffmpegState.EncoderHardwareAccelerationMode is HardwareAccelerationMode.Nvenc &&
+            currentState.FrameDataLocation is FrameDataLocation.Hardware &&
+            videoStream.ColorParams.IsUnknown &&
+            (context.HasGraphicsEngine || context.HasSubtitleOverlay || context.HasWatermark))
+        {
+            pipelineSteps.Add(new NoAutoScaleOutputOption());
+        }
+
         return new FilterChain(
             videoInputFile.FilterSteps,
             watermarkInputFile.Map(wm => wm.FilterSteps).IfNone([]),