Merge pull request #110 from Feodoros/master

Selecting streams with the -map option

FFMpegCore.Test/ArgumentBuilderTest.cs

@@ -231,6 +231,13 @@ public void Builder_BuildString_FrameOutputCount()
             Assert.AreEqual("-i \"input.mp4\" -vframes 50 \"output.mp4\"", str);
         }
 
+        [TestMethod]
+        public void Builder_BuildString_VideoStreamNumber()
+        {
+            var str = FFMpegArguments.FromFileInput("input.mp4").OutputToFile("output.mp4", false, opt => opt.SelectStream(1)).Arguments;
+            Assert.AreEqual("-i \"input.mp4\" -map 0:1 \"output.mp4\"", str);
+        }
+
         [TestMethod]
         public void Builder_BuildString_FrameRate()
         {

FFMpegCore/FFMpeg/Arguments/MapStreamArgument.cs

@@ -0,0 +1,19 @@
+namespace FFMpegCore.Arguments
+{
+    /// <summary>
+    /// Represents choice of video stream
+    /// </summary>
+    public class MapStreamArgument : IArgument
+    {
+        private readonly int _inputFileIndex;
+        private readonly int _streamIndex;
+
+        public MapStreamArgument(int streamIndex, int inputFileIndex)
+        {
+            _inputFileIndex = inputFileIndex;
+            _streamIndex = streamIndex;
+        }
+
+        public string Text => $"-map {_inputFileIndex}:{_streamIndex}";
+    }
+}

FFMpegCore/FFMpeg/FFMpeg.cs

@@ -20,14 +20,16 @@ public static class FFMpeg
         /// <param name="output">Output video file path</param>
         /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
         /// <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>
         /// <returns>Bitmap with the requested snapshot.</returns>
-        public static bool Snapshot(string input, string output, Size? size = null, TimeSpan? captureTime = null)
+        public static bool Snapshot(string input, string output, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
         {
             if (Path.GetExtension(output) != FileExtension.Png)
                 output = Path.GetFileNameWithoutExtension(output) + FileExtension.Png;
 
             var source = FFProbe.Analyse(input);
-            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime);
+            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
 
             return arguments
                 .OutputToFile(output, true, outputOptions)
@@ -40,14 +42,16 @@ public static bool Snapshot(string input, string output, Size? size = null, Time
         /// <param name="output">Output video file path</param>
         /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
         /// <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>
         /// <returns>Bitmap with the requested snapshot.</returns>
-        public static async Task<bool> SnapshotAsync(string input, string output, Size? size = null, TimeSpan? captureTime = null)
+        public static async Task<bool> SnapshotAsync(string input, string output, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
         {
             if (Path.GetExtension(output) != FileExtension.Png)
                 output = Path.GetFileNameWithoutExtension(output) + FileExtension.Png;
 
             var source = await FFProbe.AnalyseAsync(input);
-            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime);
+            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
 
             return await arguments
                 .OutputToFile(output, true, outputOptions)
@@ -60,11 +64,13 @@ public static async Task<bool> SnapshotAsync(string input, string output, Size?
         /// <param name="input">Source video file.</param>
         /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
         /// <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>
         /// <returns>Bitmap with the requested snapshot.</returns>
-        public static Bitmap Snapshot(string input, Size? size = null, TimeSpan? captureTime = null)
+        public static Bitmap Snapshot(string input, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
         {
             var source = FFProbe.Analyse(input);
-            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime);
+            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
             using var ms = new MemoryStream();
 
             arguments
@@ -82,11 +88,13 @@ public static Bitmap Snapshot(string input, Size? size = null, TimeSpan? capture
         /// <param name="input">Source video file.</param>
         /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
         /// <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>
         /// <returns>Bitmap with the requested snapshot.</returns>
-        public static async Task<Bitmap> SnapshotAsync(string input, Size? size = null, TimeSpan? captureTime = null)
+        public static async Task<Bitmap> SnapshotAsync(string input, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
         {
             var source = await FFProbe.AnalyseAsync(input);
-            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime);
+            var (arguments, outputOptions) = BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
             using var ms = new MemoryStream();
 
             await arguments
@@ -98,15 +106,23 @@ await arguments
             return new Bitmap(ms);
         }
 
-        private static (FFMpegArguments, Action<FFMpegArgumentOptions> outputOptions) BuildSnapshotArguments(string input, IMediaAnalysis source, Size? size = null, TimeSpan? captureTime = null)
+        private static (FFMpegArguments, Action<FFMpegArgumentOptions> outputOptions) BuildSnapshotArguments(
+            string input,
+            IMediaAnalysis source,
+            Size? size = null,
+            TimeSpan? captureTime = null,
+            int? streamIndex = null,
+            int inputFileIndex = 0)
         {
             captureTime ??= TimeSpan.FromSeconds(source.Duration.TotalSeconds / 3);
             size = PrepareSnapshotSize(source, size);
+            streamIndex = streamIndex == null ? 0 : source.VideoStreams.FirstOrDefault(videoStream => videoStream.Index == streamIndex).Index;
 
             return (FFMpegArguments
                 .FromFileInput(input, false, options => options
                     .Seek(captureTime)),
                 options => options
+                    .SelectStream((int)streamIndex, inputFileIndex)
                     .WithVideoCodec(VideoCodec.Png)
                     .WithFrameOutputCount(1)
                     .Resize(size));

FFMpegCore/FFMpeg/FFMpegArgumentOptions.cs

@@ -52,6 +52,7 @@ public FFMpegArgumentOptions WithVideoFilters(Action<VideoFilterOptions> videoFi
         public FFMpegArgumentOptions Seek(TimeSpan? seekTo) => WithArgument(new SeekArgument(seekTo));
         public FFMpegArgumentOptions Loop(int times) => WithArgument(new LoopArgument(times));
         public FFMpegArgumentOptions OverwriteExisting() => WithArgument(new OverwriteArgument());
+        public FFMpegArgumentOptions SelectStream(int streamIndex, int inputFileIndex = 0) => WithArgument(new MapStreamArgument(streamIndex, inputFileIndex));
 
         public FFMpegArgumentOptions ForceFormat(ContainerFormat format) => WithArgument(new ForceFormatArgument(format));
         public FFMpegArgumentOptions ForceFormat(string format) => WithArgument(new ForceFormatArgument(format));