work around buggy radeonsi hevc_vaapi behavior (#2680)

* try to workaround amd crop metadata ffmpeg bug

* limit workaround to hevc_vaapi encoder

* update changelog

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix detection of Plex Other Video libraries using `Plex Personal Media` agent
   - If the library is already detected as a Movies library in ETV, synchronization must be disabled for the library to change it to an Other Videos library
   - A warning will be logged when this scenario is detected
+- VAAPI: work around buggy ffmpeg behavior where hevc_vaapi encoder with RadeonSI driver incorrectly outputs height of 1088 instead of 1080
 
 ## [25.9.0] - 2025-11-29
 ### Added

ErsatzTV.FFmpeg/OutputOption/AmdCropMetadataWorkaroundFilter.cs

@@ -0,0 +1,34 @@
+using ErsatzTV.FFmpeg.Format;
+
+namespace ErsatzTV.FFmpeg.OutputOption;
+
+public class AmdCropMetadataWorkaroundFilter(string videoFormat, FrameSize frameSize) : OutputOption
+{
+    public override string[] OutputOptions
+    {
+        get
+        {
+            if (videoFormat is not VideoFormat.Hevc)
+            {
+                return [];
+            }
+
+            int cropPixels = frameSize.Height switch
+            {
+                1080 => 8,
+                _ => 0
+            };
+
+            if (cropPixels == 0)
+            {
+                return [];
+            }
+
+            return
+            [
+                "-bsf:v",
+                $"{videoFormat}_metadata=crop_bottom={cropPixels}"
+            ];
+        }
+    }
+}

ErsatzTV.FFmpeg/Pipeline/VaapiPipelineBuilder.cs

@@ -283,6 +283,15 @@ public class VaapiPipelineBuilder : SoftwarePipelineBuilder
             currentState,
             pipelineSteps);
 
+        if (ffmpegState.VaapiDriver == "radeonsi" &&
+            ffmpegState.EncoderHardwareAccelerationMode is HardwareAccelerationMode.Vaapi)
+        {
+            pipelineSteps.Add(
+                new AmdCropMetadataWorkaroundFilter(
+                    desiredState.VideoFormat,
+                    desiredState.CroppedSize.IfNone(desiredState.PaddedSize)));
+        }
+
         return new FilterChain(
             videoInputFile.FilterSteps,
             watermarkInputFile.Map(wm => wm.FilterSteps).IfNone([]),