From b4deb22b537b2330f13eafbcd6a609be4e2e771c Mon Sep 17 00:00:00 2001
From: la <laa@engineer.com>
Date: Fri, 9 Jun 2023 05:58:52 -0700
Subject: [PATCH] Overload for 'Snapshot' with Input Stream & Output

---
 FFMpegCore/FFMpeg/FFMpeg.cs                  | 42 ++++++++++++++++++++
 FFMpegCore/FFMpeg/SnapshotArgumentBuilder.cs | 38 +++++++++++++++---
 2 files changed, 74 insertions(+), 6 deletions(-)

diff --git a/FFMpegCore/FFMpeg/FFMpeg.cs b/FFMpegCore/FFMpeg/FFMpeg.cs
index 820d9fb..282dd88 100644
--- a/FFMpegCore/FFMpeg/FFMpeg.cs
+++ b/FFMpegCore/FFMpeg/FFMpeg.cs
@@ -2,6 +2,7 @@
 using FFMpegCore.Enums;
 using FFMpegCore.Exceptions;
 using FFMpegCore.Helpers;
+using FFMpegCore.Pipes;
 using Instances;
 
 namespace FFMpegCore
@@ -32,6 +33,27 @@ public static bool Snapshot(string input, string output, Size? size = null, Time
                 .OutputToFile(output, true, outputOptions)
                 .ProcessSynchronously();
         }
+
+        /// <summary>
+        ///     Saves a PNG thumbnail from the input video to the specified output stream.
+        /// </summary>
+        /// <param name="input">Input video stream</param>
+        /// <param name="output">Output stream to save the thumbnail</param>
+        /// <param name="size">Thumbnail size. If width or height is set to 0, the other dimension will be computed automatically.</param>
+        /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
+        /// <param name="streamIndex">Index of the selected video stream. If not specified, the primary video stream or the first video stream will be selected.</param>
+        /// <param name="inputFileIndex">Index of the input file</param>
+        /// <returns>True if the snapshot was successfully created and saved; otherwise, false.</returns>
+        public static bool Snapshot(Stream input, Stream output, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
+        {
+            var source = FFProbe.Analyse(input);
+            var (arguments, outputOptions) = SnapshotArgumentBuilder.BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
+
+            return arguments
+                .OutputToPipe(new StreamPipeSink(output), outputOptions)
+                .ProcessSynchronously();
+        }
+
         /// <summary>
         ///     Saves a 'png' thumbnail from the input video to drive
         /// </summary>
@@ -57,6 +79,26 @@ public static async Task<bool> SnapshotAsync(string input, string output, Size?
                 .ProcessAsynchronously();
         }
 
+        /// <summary>
+        ///     Saves a PNG thumbnail from the input video to the specified output stream.
+        /// </summary>
+        /// <param name="input">Input video stream</param>
+        /// <param name="output">Output stream to save the thumbnail</param>
+        /// <param name="size">Thumbnail size. If width or height is set to 0, the other dimension will be computed automatically.</param>
+        /// <param name="captureTime">Seek position where the thumbnail should be taken.</param>
+        /// <param name="streamIndex">Index of the selected video stream. If not specified, the primary video stream or the first video stream will be selected.</param>
+        /// <param name="inputFileIndex">Index of the input file</param>
+        /// <returns>True if the snapshot was successfully created and saved; otherwise, false.</returns>
+        public static async Task<bool> SnapshotAsync(Stream input, Stream output, Size? size = null, TimeSpan? captureTime = null, int? streamIndex = null, int inputFileIndex = 0)
+        {
+            var source = await FFProbe.AnalyseAsync(input).ConfigureAwait(false);
+            var (arguments, outputOptions) = SnapshotArgumentBuilder.BuildSnapshotArguments(input, source, size, captureTime, streamIndex, inputFileIndex);
+
+            return await arguments
+                .OutputToPipe(new StreamPipeSink(output), outputOptions)
+                .ProcessAsynchronously();
+        }
+
         public static bool GifSnapshot(string input, string output, Size? size = null, TimeSpan? captureTime = null, TimeSpan? duration = null, int? streamIndex = null)
         {
             if (Path.GetExtension(output)?.ToLower() != FileExtension.Gif)
diff --git a/FFMpegCore/FFMpeg/SnapshotArgumentBuilder.cs b/FFMpegCore/FFMpeg/SnapshotArgumentBuilder.cs
index 0d9b414..eafe57b 100644
--- a/FFMpegCore/FFMpeg/SnapshotArgumentBuilder.cs
+++ b/FFMpegCore/FFMpeg/SnapshotArgumentBuilder.cs
@@ -2,6 +2,7 @@
 
 using System.Drawing;
 using FFMpegCore.Enums;
+using FFMpegCore.Pipes;
 
 namespace FFMpegCore;
 
@@ -31,13 +32,38 @@ public static (FFMpegArguments, Action<FFMpegArgumentOptions> outputOptions) Bui
                 .Resize(size));
     }
 
+    public static (FFMpegArguments, Action<FFMpegArgumentOptions> outputOptions) BuildSnapshotArguments(
+      Stream inputStream,
+      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 ??= source.PrimaryVideoStream?.Index
+                        ?? source.VideoStreams.FirstOrDefault()?.Index
+                        ?? 0;
+
+        return (FFMpegArguments
+                .FromPipeInput(new StreamPipeSource(inputStream), options => options
+                    .Seek(captureTime)), 
+            options => options
+                .SelectStream((int)streamIndex, inputFileIndex)
+                .WithVideoCodec(VideoCodec.Png)
+                .WithFrameOutputCount(1)
+                .Resize(size)
+        );
+    }
+
     public static (FFMpegArguments, Action<FFMpegArgumentOptions> outputOptions) BuildGifSnapshotArguments(
-        string input,
-        IMediaAnalysis source,
-        Size? size = null,
-        TimeSpan? captureTime = null,
-        TimeSpan? duration = null,
-        int? streamIndex = null,
+      string input,
+      IMediaAnalysis source,
+      Size? size = null,
+      TimeSpan? captureTime = null,
+      TimeSpan? duration = null,
+    int? streamIndex = null,
         int fps = 12)
     {
         var defaultGifOutputSize = new Size(480, -1);