fix decimal separator in ffmpeg apad filter syntax (#464)

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Fixed
+- Fix bug with audio filter in cultures where `.` is a group/thousands separator
 
 ## [0.2.2-alpha] - 2021-10-30
 ### Fixed

ErsatzTV.Core.Tests/FFmpeg/FFmpegComplexFilterBuilderTests.cs

@@ -27,7 +27,28 @@ namespace ErsatzTV.Core.Tests.FFmpeg
             [Test]
             public void Should_Return_Audio_Filter_With_AudioDuration()
             {
-                var duration = TimeSpan.FromMinutes(54);
+                var duration = TimeSpan.FromMilliseconds(1000.1);
+                FFmpegComplexFilterBuilder builder = new FFmpegComplexFilterBuilder()
+                    .WithAlignedAudio(duration);
+
+                Option<FFmpegComplexFilter> result = builder.Build(0, 1);
+
+                result.IsSome.Should().BeTrue();
+                result.IfSome(
+                    filter =>
+                    {
+                        filter.ComplexFilter.Should().Be("[0:1]apad=whole_dur=1000.1ms[a]");
+                        filter.AudioLabel.Should().Be("[a]");
+                        filter.VideoLabel.Should().Be("0:0");
+                    });
+            }
+            
+            [Test]
+            // this needs to be a culture where '.' is a group separator
+            [SetCulture("it-IT")] 
+            public void Should_Return_Audio_Filter_With_AudioDuration_Decimal()
+            {
+                var duration = TimeSpan.FromMilliseconds(1000.1);
                 FFmpegComplexFilterBuilder builder = new FFmpegComplexFilterBuilder()
                     .WithAlignedAudio(duration);
 
@@ -37,7 +58,7 @@ namespace ErsatzTV.Core.Tests.FFmpeg
                 result.IfSome(
                     filter =>
                     {
-                        filter.ComplexFilter.Should().Be($"[0:1]apad=whole_dur={duration.TotalMilliseconds}ms[a]");
+                        filter.ComplexFilter.Should().Be("[0:1]apad=whole_dur=1000.1ms[a]");
                         filter.AudioLabel.Should().Be("[a]");
                         filter.VideoLabel.Should().Be("0:0");
                     });

ErsatzTV.Core/FFmpeg/FFmpegComplexFilterBuilder.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Text;
 using ErsatzTV.Core.Domain;
@@ -111,7 +112,11 @@ namespace ErsatzTV.Core.FFmpeg
             }
 
             _audioDuration.IfSome(
-                audioDuration => audioFilterQueue.Add($"apad=whole_dur={audioDuration.TotalMilliseconds}ms"));
+                audioDuration =>
+                {
+                    var durationString = audioDuration.TotalMilliseconds.ToString(NumberFormatInfo.InvariantInfo);
+                    audioFilterQueue.Add($"apad=whole_dur={durationString}ms");
+                });
 
             bool usesHardwareFilters = acceleration != HardwareAccelerationKind.None && !isHardwareDecode &&
                                        (_deinterlace || _scaleToSize.IsSome);