Move cancellation check outside of the ThrowIfExitCodeNotZero() and call it separately in all the async code paths.

This preserves the original semantics and contract (throw only if the ffprobe exits with a non-zero code).

FFMpegCore.Test/FFProbeTests.cs

@@ -1,4 +1,5 @@
-using FFMpegCore.Test.Resources;
+using FFMpegCore.Exceptions;
+using FFMpegCore.Test.Resources;
 
 namespace FFMpegCore.Test;
 
@@ -285,4 +286,70 @@ public class FFProbeTests
         var info = FFProbe.Analyse(TestResources.Mp4Video, customArguments: "-headers \"Hello: World\"");
         Assert.AreEqual(3, info.Duration.Seconds);
     }
+
+    [TestMethod]
+    [Timeout(10000, CooperativeCancellation = true)]
+    public async Task Parallel_FFProbe_Cancellation_Should_Throw_Only_OperationCanceledException()
+    {
+        // Warm up FFMpegCore environment
+        Helpers.FFProbeHelper.VerifyFFProbeExists(GlobalFFOptions.Current);
+
+        var mp4 = TestResources.Mp4Video;
+        if (!File.Exists(mp4))
+        {
+            Assert.Inconclusive($"Test video not found: {mp4}");
+            return;
+        }
+
+        var cts = CancellationTokenSource.CreateLinkedTokenSource(TestContext.CancellationToken);
+        var token = cts.Token;
+        using var semaphore = new SemaphoreSlim(Environment.ProcessorCount, Environment.ProcessorCount);
+        var tasks = Enumerable.Range(0, 50).Select(x => Task.Run(async () =>
+        {
+            await semaphore.WaitAsync(token);
+            try
+            {
+                var analysis = await FFProbe.AnalyseAsync(mp4, cancellationToken: token);
+                return analysis;
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }, token)).ToList();
+
+        // Wait for 2 tasks to finish, then cancel all
+        await Task.WhenAny(tasks);
+        await Task.WhenAny(tasks);
+        await cts.CancelAsync();
+        cts.Dispose();
+
+        var exceptions = new List<Exception>();
+        foreach (var task in tasks)
+        {
+            try
+            {
+                await task;
+            }
+            catch (Exception e)
+            {
+                exceptions.Add(e);
+            }
+        }
+
+        Assert.IsNotEmpty(exceptions, "No exceptions were thrown on cancellation. Test was useless. " +
+                                      ".Try adjust cancellation timings to make cancellation at the moment, when ffprobe is still running.");
+
+        // Check that all exceptions are OperationCanceledException
+        CollectionAssert.AllItemsAreInstancesOfType(exceptions, typeof(OperationCanceledException));
+    }
+
+    [TestMethod]
+    [Timeout(10000, CooperativeCancellation = true)]
+    public async Task FFProbe_Should_Throw_FFMpegException_When_Exits_With_Non_Zero_Code()
+    {
+        var input = TestResources.SrtSubtitle; //non media file
+        await Assert.ThrowsAsync<FFMpegException>(async () => await FFProbe.AnalyseAsync(input,
+            cancellationToken: TestContext.CancellationToken, customArguments: "--some-invalid-argument"));
+    }
 }

FFMpegCore.Test/VideoTest.cs

@@ -82,6 +82,40 @@ public class VideoTest
         Assert.IsTrue(success);
     }
 
+    [TestMethod]
+    [Timeout(BaseTimeoutMilliseconds, CooperativeCancellation = true)]
+    public async Task Video_MetadataBuilder()
+    {
+        using var outputFile = new TemporaryFile($"out{VideoType.Mp4.Extension}");
+
+        await FFMpegArguments
+            .FromFileInput(TestResources.WebmVideo)
+            .AddMetaData(FFMetadataBuilder.Empty()
+                .WithTag("title", "noname")
+                .WithTag("artist", "unknown")
+                .WithChapter("Chapter 1", 1.1)
+                .WithChapter("Chapter 2", 1.23))
+            .OutputToFile(outputFile, false, opt => opt
+                .WithVideoCodec(VideoCodec.LibX264))
+            .CancellableThrough(TestContext.CancellationToken)
+            .ProcessAsynchronously();
+
+        var analysis = await FFProbe.AnalyseAsync(outputFile, cancellationToken: TestContext.CancellationToken);
+        Assert.IsTrue(analysis.Format.Tags!.TryGetValue("title", out var title));
+        Assert.IsTrue(analysis.Format.Tags!.TryGetValue("artist", out var artist));
+        Assert.AreEqual("noname", title);
+        Assert.AreEqual("unknown", artist);
+
+        Assert.HasCount(2, analysis.Chapters);
+        Assert.AreEqual("Chapter 1", analysis.Chapters.First().Title);
+        Assert.AreEqual(1.1, analysis.Chapters.First().Duration.TotalSeconds);
+        Assert.AreEqual(1.1, analysis.Chapters.First().End.TotalSeconds);
+
+        Assert.AreEqual("Chapter 2", analysis.Chapters.Last().Title);
+        Assert.AreEqual(1.23, analysis.Chapters.Last().Duration.TotalSeconds);
+        Assert.AreEqual(1.1 + 1.23, analysis.Chapters.Last().End.TotalSeconds);
+    }
+
     [TestMethod]
     [Timeout(BaseTimeoutMilliseconds, CooperativeCancellation = true)]
     public void Video_ToH265_MKV_Args()

FFMpegCore/FFMetadataInputArgument.cs

@@ -0,0 +1,62 @@
+using System.Text;
+
+namespace FFMpegCore;
+
+public class FFMetadataBuilder
+{
+    private Dictionary<string, string> Tags { get; } = new();
+    private List<FFMetadataChapter> Chapters { get; } = [];
+
+    public static FFMetadataBuilder Empty()
+    {
+        return new FFMetadataBuilder();
+    }
+
+    public FFMetadataBuilder WithTag(string key, string value)
+    {
+        Tags.Add(key, value);
+        return this;
+    }
+
+    public FFMetadataBuilder WithChapter(string title, long durationMs)
+    {
+        Chapters.Add(new FFMetadataChapter(title, durationMs));
+        return this;
+    }
+
+    public FFMetadataBuilder WithChapter(string title, double durationSeconds)
+    {
+        Chapters.Add(new FFMetadataChapter(title, Convert.ToInt64(durationSeconds * 1000)));
+        return this;
+    }
+
+    public string GetMetadataFileContent()
+    {
+        var sb = new StringBuilder();
+        sb.AppendLine(";FFMETADATA1");
+
+        foreach (var tag in Tags)
+        {
+            sb.AppendLine($"{tag.Key}={tag.Value}");
+        }
+
+        long totalDurationMs = 0;
+        foreach (var chapter in Chapters)
+        {
+            sb.AppendLine("[CHAPTER]");
+            sb.AppendLine("TIMEBASE=1/1000");
+            sb.AppendLine($"START={totalDurationMs}");
+            sb.AppendLine($"END={totalDurationMs + chapter.DurationMs}");
+            sb.AppendLine($"title={chapter.Title}");
+            totalDurationMs += chapter.DurationMs;
+        }
+
+        return sb.ToString();
+    }
+
+    private class FFMetadataChapter(string title, long durationMs)
+    {
+        public string Title { get; } = title;
+        public long DurationMs { get; } = durationMs;
+    }
+}

FFMpegCore/FFMpeg/FFMpegArguments.cs

@@ -109,6 +109,11 @@ public sealed class FFMpegArguments : FFMpegArgumentsBase
         return WithInput(new MetaDataArgument(content), addArguments);
     }
 
+    public FFMpegArguments AddMetaData(FFMetadataBuilder metaDataBuilder, Action<FFMpegArgumentOptions>? addArguments = null)
+    {
+        return WithInput(new MetaDataArgument(metaDataBuilder.GetMetadataFileContent()), addArguments);
+    }
+
     public FFMpegArguments AddMetaData(IReadOnlyMetaData metaData, Action<FFMpegArgumentOptions>? addArguments = null)
     {
         return WithInput(new MetaDataArgument(MetaDataSerializer.Instance.Serialize(metaData)), addArguments);

FFMpegCore/FFProbe/FFProbe.cs

@@ -84,6 +84,7 @@ public static class FFProbe
 
         var instance = PrepareStreamAnalysisInstance(filePath, ffOptions ?? GlobalFFOptions.Current, customArguments);
         var result = await instance.StartAndWaitForExitAsync(cancellationToken).ConfigureAwait(false);
+        cancellationToken.ThrowIfCancellationRequested();
         ThrowIfExitCodeNotZero(result);
 
         return ParseOutput(result);
@@ -123,6 +124,7 @@ public static class FFProbe
     {
         var instance = PrepareStreamAnalysisInstance(uri.AbsoluteUri, ffOptions ?? GlobalFFOptions.Current, customArguments);
         var result = await instance.StartAndWaitForExitAsync(cancellationToken).ConfigureAwait(false);
+        cancellationToken.ThrowIfCancellationRequested();
         ThrowIfExitCodeNotZero(result);
 
         return ParseOutput(result);
@@ -150,6 +152,7 @@ public static class FFProbe
         }
 
         var result = await task.ConfigureAwait(false);
+        cancellationToken.ThrowIfCancellationRequested();
         ThrowIfExitCodeNotZero(result);
 
         pipeArgument.Post();

FFMpegCore/FFProbe/ProcessArgumentsExtensions.cs

@@ -13,6 +13,6 @@ public static class ProcessArgumentsExtensions
     public static async Task<IProcessResult> StartAndWaitForExitAsync(this ProcessArguments processArguments, CancellationToken cancellationToken = default)
     {
         using var instance = processArguments.Start();
-        return await instance.WaitForExitAsync(cancellationToken);
+        return await instance.WaitForExitAsync(cancellationToken).ConfigureAwait(false);
     }
 }