remove some decode threading limits (#2103)

CHANGELOG.md

@@ -68,6 +68,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Try to mitigate inotify limit error by disabling automatic reloading of `appsettings.json` config files
 - Support `movie`, `musicvideo` and `episodedetails` top-level tags in other video NFO files
   - Note that no change has been made to the metadata tags that are actually parsed, but this should help with various types of content
+- Remove some limits on multithreading that are no longer needed with latest ffmpeg
+  - Mixed transcoding (software decode, hardware filters/encode) can now use multiple decode threads
 
 ### Fixed
 - Fix QSV acceleration in docker with older Intel devices

ErsatzTV.FFmpeg.Tests/PipelineBuilderBaseTests.cs

@@ -115,7 +115,7 @@ public class PipelineBuilderBaseTests
 
         string command = PrintCommand(videoInputFile, audioInputFile, None, None, result);
         command.ShouldBe(
-            "-threads 1 -nostdin -hide_banner -nostats -loglevel error -fflags +genpts+discardcorrupt+igndts -ss 00:00:01 -c:v h264 -readrate 1.0 -i /tmp/whatever.mkv -filter_complex [0:1]aresample=async=1:first_pts=0[a] -map 0:0 -map [a] -muxdelay 0 -muxpreload 0 -movflags +faststart -flags cgop -bf 0 -sc_threshold 0 -video_track_timescale 90000 -b:v 2000k -maxrate:v 2000k -bufsize:v 4000k -c:v libx265 -tag:v hvc1 -x265-params log-level=error -c:a aac -b:a 320k -maxrate:a 320k -bufsize:a 640k -ar 48k -f mpegts -mpegts_flags +initial_discontinuity pipe:1");
+            "-nostdin -hide_banner -nostats -loglevel error -fflags +genpts+discardcorrupt+igndts -ss 00:00:01 -c:v h264 -readrate 1.0 -i /tmp/whatever.mkv -filter_complex [0:1]aresample=async=1:first_pts=0[a] -map 0:0 -map [a] -muxdelay 0 -muxpreload 0 -movflags +faststart -flags cgop -bf 0 -sc_threshold 0 -video_track_timescale 90000 -b:v 2000k -maxrate:v 2000k -bufsize:v 4000k -c:v libx265 -tag:v hvc1 -x265-params log-level=error -c:a aac -b:a 320k -maxrate:a 320k -bufsize:a 640k -ar 48k -f mpegts -mpegts_flags +initial_discontinuity pipe:1");
     }
 
     [Test]
@@ -211,7 +211,7 @@ public class PipelineBuilderBaseTests
 
         string command = PrintCommand(videoInputFile, audioInputFile, None, None, result);
         command.ShouldBe(
-            "-threads 1 -nostdin -hide_banner -nostats -loglevel error -fflags +genpts+discardcorrupt+igndts -ss 00:00:01 -c:v h264 -readrate 1.0 -i /tmp/whatever.mkv -filter_complex [0:1]aresample=async=1:first_pts=0[a] -map 0:0 -map [a] -muxdelay 0 -muxpreload 0 -movflags +faststart -flags cgop -bf 0 -sc_threshold 0 -video_track_timescale 90000 -b:v 2000k -maxrate:v 2000k -bufsize:v 4000k -c:v libx265 -tag:v hvc1 -x265-params log-level=error -c:a aac -ac 6 -b:a 320k -maxrate:a 320k -bufsize:a 640k -ar 48k -f mpegts -mpegts_flags +initial_discontinuity pipe:1");
+            "-nostdin -hide_banner -nostats -loglevel error -fflags +genpts+discardcorrupt+igndts -ss 00:00:01 -c:v h264 -readrate 1.0 -i /tmp/whatever.mkv -filter_complex [0:1]aresample=async=1:first_pts=0[a] -map 0:0 -map [a] -muxdelay 0 -muxpreload 0 -movflags +faststart -flags cgop -bf 0 -sc_threshold 0 -video_track_timescale 90000 -b:v 2000k -maxrate:v 2000k -bufsize:v 4000k -c:v libx265 -tag:v hvc1 -x265-params log-level=error -c:a aac -ac 6 -b:a 320k -maxrate:a 320k -bufsize:a 640k -ar 48k -f mpegts -mpegts_flags +initial_discontinuity pipe:1");
     }
 
     [Test]

ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs

@@ -202,13 +202,12 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
             false,
             videoStream.ColorParams.IsHdr);
 
-        SetThreadCount(ffmpegState, desiredState, pipelineSteps);
         SetSceneDetect(videoStream, ffmpegState, desiredState, pipelineSteps);
         SetFFReport(ffmpegState, pipelineSteps);
         SetStreamSeek(ffmpegState, videoInputFile, context, pipelineSteps);
         SetTimeLimit(ffmpegState, pipelineSteps);
 
-        FilterChain filterChain = BuildVideoPipeline(
+        (FilterChain filterChain, ffmpegState) = BuildVideoPipeline(
             videoInputFile,
             videoStream,
             ffmpegState,
@@ -216,6 +215,8 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
             context,
             pipelineSteps);
 
+        SetThreadCount(ffmpegState, pipelineSteps);
+
         // don't double input files for concat segmenter (v2) parent or child
         if (_concatInputFile.IsNone && ffmpegState.OutputFormat is not OutputFormatKind.Nut)
         {
@@ -483,7 +484,7 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
         PipelineContext context,
         ICollection<IPipelineStep> pipelineSteps);
 
-    private FilterChain BuildVideoPipeline(
+    private FilterChainAndState BuildVideoPipeline(
         VideoInputFile videoInputFile,
         VideoStream videoStream,
         FFmpegState ffmpegState,
@@ -514,7 +515,7 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
             : SetDecoder(videoInputFile, videoStream, ffmpegState, context);
 
         //SetStillImageInfiniteLoop(videoInputFile, videoStream, ffmpegState);
-        SetRealtimeInput(videoInputFile, ffmpegState, desiredState);
+        SetRealtimeInput(videoInputFile, desiredState);
         SetInfiniteLoop(videoInputFile, videoStream, ffmpegState, desiredState);
         SetFrameRateOutput(desiredState, pipelineSteps);
         SetVideoTrackTimescaleOutput(desiredState, pipelineSteps);
@@ -539,7 +540,7 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
 
         SetOutputTsOffset(ffmpegState, desiredState, pipelineSteps);
 
-        return filterChain;
+        return new FilterChainAndState(filterChain, ffmpegState);
     }
 
     protected abstract Option<IDecoder> SetDecoder(
@@ -707,7 +708,7 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
         }
     }
 
-    private void SetRealtimeInput(VideoInputFile videoInputFile, FFmpegState ffmpegState, FrameState desiredState)
+    private void SetRealtimeInput(VideoInputFile videoInputFile, FrameState desiredState)
     {
         int initialBurst;
         if (!desiredState.Realtime)
@@ -758,21 +759,12 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
         }
     }
 
-    private void SetThreadCount(FFmpegState ffmpegState, FrameState desiredState, List<IPipelineStep> pipelineSteps)
+    private void SetThreadCount(FFmpegState ffmpegState, List<IPipelineStep> pipelineSteps)
     {
-        if (ffmpegState.DecoderHardwareAccelerationMode != HardwareAccelerationMode.None ||
-            ffmpegState.EncoderHardwareAccelerationMode != HardwareAccelerationMode.None)
-        {
-            _logger.LogDebug(
-                "Forcing {Threads} ffmpeg thread when hardware acceleration is used",
-                1);
-
-            pipelineSteps.Insert(0, new ThreadCountOption(1));
-        }
-        else if (ffmpegState.Start.Exists(s => s > TimeSpan.Zero) && desiredState.Realtime)
+        if (ffmpegState.DecoderHardwareAccelerationMode != HardwareAccelerationMode.None)
         {
             _logger.LogDebug(
-                "Forcing {Threads} ffmpeg thread due to buggy combination of stream seek and realtime output",
+                "Forcing {Threads} ffmpeg decoding thread when hardware acceleration is used",
                 1);
 
             pipelineSteps.Insert(0, new ThreadCountOption(1));
@@ -835,4 +827,6 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
 
     private static void SetTimeLimit(FFmpegState ffmpegState, List<IPipelineStep> pipelineSteps) =>
         pipelineSteps.AddRange(ffmpegState.Finish.Map(finish => new TimeLimitOutputOption(finish)));
+
+    private sealed record FilterChainAndState(FilterChain FilterChain, FFmpegState FFmpegState);
 }