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Add cancellation token support for the [Gif]SnapshotAsync #593

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Merged
rosenbjerg merged 3 commits into from
Oct 27, 2025
Merged

Add cancellation token support for the [Gif]SnapshotAsync #593

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b3c201b
Add cancellation token support to SnapshotAsync, GifSnapshotAsync and…
snechaev Oct 21, 2025
f5ecbae
Fixed a race condition that occurred when handling the cancellation o…
snechaev Oct 21, 2025
935e1cf
Merge branch 'main' into PR-592_Snapshot_Cancellation_Support
rosenbjerg Oct 27, 2025
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9 changes: 6 additions & 3 deletions FFMpegCore.Extensions.SkiaSharp/FFMpegImage.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,18 +39,21 @@ public static SKBitmap Snapshot(string input, Size? size = null, TimeSpan? captu
/// <param name="size">Thumbnail size. If width or height equal 0, the other will be computed automatically.</param>
/// <param name="streamIndex">Selected video stream index.</param>
/// <param name="inputFileIndex">Input file index</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Bitmap with the requested snapshot.</returns>
public static async Task<SKBitmap> SnapshotAsync(string input, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null,
int inputFileIndex = 0)
int inputFileIndex = 0, CancellationToken cancellationToken = default)
{
var source = await FFProbe.AnalyseAsync(input).ConfigureAwait(false);
var source = await FFProbe.AnalyseAsync(input, cancellationToken: cancellationToken).ConfigureAwait(false);
var (arguments, outputOptions) = SnapshotArgumentBuilder.BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
using var ms = new MemoryStream();

await arguments
.OutputToPipe(new StreamPipeSink(ms), options => outputOptions(options
.ForceFormat("rawvideo")))
.ProcessAsynchronously();
.CancellableThrough(cancellationToken)
.ProcessAsynchronously()
.ConfigureAwait(false);

ms.Position = 0;
return SKBitmap.Decode(ms);
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9 changes: 6 additions & 3 deletions FFMpegCore.Extensions.System.Drawing.Common/FFMpegImage.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -38,18 +38,21 @@ public static Bitmap Snapshot(string input, Size? size = null, TimeSpan? capture
/// <param name="size">Thumbnail size. If width or height equal 0, the other will be computed automatically.</param>
/// <param name="streamIndex">Selected video stream index.</param>
/// <param name="inputFileIndex">Input file index</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Bitmap with the requested snapshot.</returns>
public static async Task<Bitmap> SnapshotAsync(string input, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null,
int inputFileIndex = 0)
int inputFileIndex = 0, CancellationToken cancellationToken = default)
{
var source = await FFProbe.AnalyseAsync(input).ConfigureAwait(false);
var source = await FFProbe.AnalyseAsync(input, cancellationToken: cancellationToken).ConfigureAwait(false);
var (arguments, outputOptions) = SnapshotArgumentBuilder.BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
using var ms = new MemoryStream();

await arguments
.OutputToPipe(new StreamPipeSink(ms), options => outputOptions(options
.ForceFormat("rawvideo")))
.ProcessAsynchronously();
.CancellableThrough(cancellationToken)
.ProcessAsynchronously()
.ConfigureAwait(false);

ms.Position = 0;
return new Bitmap(ms);
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6 changes: 4 additions & 2 deletions FFMpegCore.Test/VideoTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -732,7 +732,8 @@ public async Task Video_GifSnapshot_PersistSnapshotAsync()
using var outputPath = new TemporaryFile("out.gif");
var input = FFProbe.Analyse(TestResources.Mp4Video);

await FFMpeg.GifSnapshotAsync(TestResources.Mp4Video, outputPath, captureTime: TimeSpan.FromSeconds(0));
await FFMpeg.GifSnapshotAsync(TestResources.Mp4Video, outputPath, captureTime: TimeSpan.FromSeconds(0),
cancellationToken: TestContext.CancellationToken);

var analysis = FFProbe.Analyse(outputPath);
Assert.AreNotEqual(input.PrimaryVideoStream!.Width, analysis.PrimaryVideoStream!.Width);
Expand All @@ -748,7 +749,8 @@ public async Task Video_GifSnapshot_PersistSnapshotAsync_SizeSupplied()
var input = FFProbe.Analyse(TestResources.Mp4Video);
var desiredGifSize = new Size(320, 240);

await FFMpeg.GifSnapshotAsync(TestResources.Mp4Video, outputPath, desiredGifSize, TimeSpan.FromSeconds(0));
await FFMpeg.GifSnapshotAsync(TestResources.Mp4Video, outputPath, desiredGifSize, TimeSpan.FromSeconds(0),
cancellationToken: TestContext.CancellationToken);

var analysis = FFProbe.Analyse(outputPath);
Assert.AreNotEqual(input.PrimaryVideoStream!.Width, desiredGifSize.Width);
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25 changes: 17 additions & 8 deletions FFMpegCore/FFMpeg/FFMpeg.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,16 +37,19 @@ public static bool Snapshot(string input, string output, Size? size = null, Time
/// <param name="size">Thumbnail size. If width or height equal 0, the other will be computed automatically.</param>
/// <param name="streamIndex">Selected video stream index.</param>
/// <param name="inputFileIndex">Input file index</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Bitmap with the requested snapshot.</returns>
public static async Task<bool> SnapshotAsync(string input, string output, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null,
int inputFileIndex = 0)
int inputFileIndex = 0, CancellationToken cancellationToken = default)
{
CheckSnapshotOutputExtension(output, FileExtension.Image.All);

var source = await FFProbe.AnalyseAsync(input).ConfigureAwait(false);
var source = await FFProbe.AnalyseAsync(input, cancellationToken: cancellationToken).ConfigureAwait(false);

return await SnapshotProcess(input, output, source, size, captureTime, streamIndex, inputFileIndex)
.ProcessAsynchronously();
.CancellableThrough(cancellationToken)
.ProcessAsynchronously()
.ConfigureAwait(false);
}

public static bool GifSnapshot(string input, string output, Size? size = null, TimeSpan? captureTime = null, TimeSpan? duration = null,
Expand All @@ -61,14 +64,16 @@ public static bool GifSnapshot(string input, string output, Size? size = null, T
}

public static async Task<bool> GifSnapshotAsync(string input, string output, Size? size = null, TimeSpan? captureTime = null, TimeSpan? duration = null,
int? streamIndex = null)
int? streamIndex = null, CancellationToken cancellationToken = default)
{
CheckSnapshotOutputExtension(output, [FileExtension.Gif]);

var source = await FFProbe.AnalyseAsync(input).ConfigureAwait(false);
var source = await FFProbe.AnalyseAsync(input, cancellationToken: cancellationToken).ConfigureAwait(false);

return await GifSnapshotProcess(input, output, source, size, captureTime, duration, streamIndex)
.ProcessAsynchronously();
.CancellableThrough(cancellationToken)
.ProcessAsynchronously()
.ConfigureAwait(false);
}

private static FFMpegArgumentProcessor SnapshotProcess(string input, string output, IMediaAnalysis source, Size? size = null, TimeSpan? captureTime = null,
Expand Down Expand Up @@ -321,11 +326,15 @@ public static bool SubVideo(string input, string output, TimeSpan startTime, Tim
/// <param name="output">Output video file.</param>
/// <param name="startTime">The start time of when the sub video needs to start</param>
/// <param name="endTime">The end time of where the sub video needs to end</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Output video information.</returns>
public static async Task<bool> SubVideoAsync(string input, string output, TimeSpan startTime, TimeSpan endTime)
public static async Task<bool> SubVideoAsync(string input, string output, TimeSpan startTime, TimeSpan endTime,
CancellationToken cancellationToken = default)
{
return await BaseSubVideo(input, output, startTime, endTime)
.ProcessAsynchronously();
.CancellableThrough(cancellationToken)
.ProcessAsynchronously()
.ConfigureAwait(false);
}

/// <summary>
Expand Down
20 changes: 18 additions & 2 deletions FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs
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Expand Up @@ -166,12 +166,28 @@ private async Task<IProcessResult> Process(ProcessArguments processArguments, Ca

void OnCancelEvent(object sender, int timeout)
{
instance.SendInput("q");
ExecuteIgnoringFinishedProcessExceptions(() => instance.SendInput("q"));

if (!cancellationTokenSource.Token.WaitHandle.WaitOne(timeout, true))
{
cancellationTokenSource.Cancel();
instance.Kill();
ExecuteIgnoringFinishedProcessExceptions(() => instance.Kill());
}

static void ExecuteIgnoringFinishedProcessExceptions(Action action)
{
try
{
action();
}
catch (Instances.Exceptions.InstanceProcessAlreadyExitedException)
{
//ignore
}
catch (ObjectDisposedException)
{
//ignore
}
}
}

Expand Down