Support fixed bitrate encoding

BassAudio.Tests/Integration/AudioEncoderTests.cs

@@ -218,6 +218,27 @@ public async Task Start_Bitrate_CreateFileOfSize(EncodeFormat format, int bitrat
         var fileLength = FileSystem.FileInfo.New(file.Destination).Length;
         Output.WriteLine(fileLength.ToString());
     }
+
+    [Theory]
+    [InlineData(0)]
+    [InlineData(32)]
+    [InlineData(128)]
+    [InlineData(256)]
+    [InlineData(320)]
+    public async Task Start_FixedBitrate_CreateFileOfSize(int bitrate)
+    {
+        var file = CreateSourceShort(EncodeFormat.Mp3);
+        FileSystem.DeleteFileSilent(file.Destination);
+        Settings.Format = EncodeFormat.Mp3;
+        Settings.FixedBitrate = true;
+        Settings.Bitrate = bitrate;
+
+        await Model.StartAsync(file, Settings);
+
+        Assert.True(FileSystem.File.Exists(file.Destination));
+        var fileLength = FileSystem.FileInfo.New(file.Destination).Length;
+        Output.WriteLine(fileLength.ToString());
+    }
 
     [Theory]
     [MemberData(nameof(GetAllSampleRates))]

BassAudio/AudioEncoder.cs

@@ -3,6 +3,7 @@
 using ManagedBass.Enc;
 using ManagedBass.Fx;
 using ManagedBass.Mix;
+
 // ReSharper disable StringLiteralTypo
 
 namespace HanumanInstitute.BassAudio;
@@ -46,10 +47,10 @@ public void Start(ProcessingItem file, EncodeSettings settings, CancellationToke
         {
             file.Pitch ??= _pitchDetector.GetPitch(file.Path);
         }
-        var pitch = settings.AutoDetectPitch ? 
-            settings.PitchTo / file.Pitch!.Value : 
+        var pitch = settings.AutoDetectPitch ?
+            settings.PitchTo / file.Pitch!.Value :
             settings.Pitch;
-        
+
         // Create channel.
         Bass.Configure(Configuration.SRCQuality, 4);
         Bass.Configure(Configuration.FloatDSP, true);
@@ -59,12 +60,12 @@ public void Start(ProcessingItem file, EncodeSettings settings, CancellationToke
         try
         {
             var tags = new TagsReader(chan);
-            
+
             var chanInfo = Bass.ChannelGetInfo(chan);
             var bitrate = (int)Bass.ChannelGetAttribute(chan, ChannelAttribute.Bitrate);
             bitrate = BitrateRoundUp(bitrate);
             var length = Bass.ChannelGetLength(chan);
-                        
+
             // Add mix effect.
             var sampleRate = settings.SampleRate > 0 ? settings.SampleRate : chanInfo.Frequency;
             sampleRate = EnsureSampleRateValid(settings.Format, sampleRate);
@@ -83,7 +84,7 @@ public void Start(ProcessingItem file, EncodeSettings settings, CancellationToke
             // Bass.ChannelSetAttribute(chan, ChannelAttribute.Tempo, (1.0 / pitch * settings.Speed - 1.0) * 100.0);
             // Bass.ChannelSetAttribute(chan, ChannelAttribute.TempoFrequency,
             //     chanInfo.Frequency * pitch * settings.Rate);
-            
+
             // Optimized pitch shifting for increased quality
             // 1. Rate shift to Output * Pitch (rounded)
             // 2. Resample to Output (48000Hz)
@@ -183,11 +184,13 @@ private string GetOptions(EncodeSettings settings, int sourceBitrate, ChannelInf
 
         return settings.Format switch
         {
-            EncodeFormat.Mp3 => $"--abr {bitrate} -q {settings.Mp3QualitySpeed} --add-id3v2"
-                .AddTag("--tt", tags.Title).AddTag("--ta", tags.Artist).AddTag("--tl", tags.Album).AddTag("--ty", tags.Year)
+            EncodeFormat.Mp3 => (settings.FixedBitrate ? "-b" : "--abr") + $" {bitrate} -q {settings.Mp3QualitySpeed} --add-id3v2"
+                .AddTag("--tt", tags.Title).AddTag("--ta", tags.Artist).AddTag("--tl", tags.Album)
+                .AddTag("--ty", tags.Year)
                 .AddTag("--tc", tags.Comment).AddTag("--tn", tags.Track).AddTag("--tg", tags.Genre),
             EncodeFormat.Flac => $"--compression-level-{settings.FlacCompression}"
-                .AddTag("-T title=", tags.Title).AddTag("-T artist=", tags.Artist).AddTag("-T album=", tags.Album).AddTag("--date", tags.Year)
+                .AddTag("-T title=", tags.Title).AddTag("-T artist=", tags.Artist).AddTag("-T album=", tags.Album)
+                .AddTag("--date", tags.Year)
                 .AddTag("-T comment=", tags.Comment).AddTag("-T tracknum=", tags.Track).AddTag("-T genre=", tags.Genre),
             EncodeFormat.Ogg => $"--bitrate {bitrate}"
                 .AddTag("--title", tags.Title).AddTag("--artist", tags.Artist).AddTag("--album", tags.Album).AddTag("--date", tags.Year)

BassAudio/Models/EncodeSettings.cs

@@ -1,4 +1,4 @@
-using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations;
 using ReactiveUI;
 
 namespace HanumanInstitute.BassAudio;
@@ -20,11 +20,17 @@ public class EncodeSettings : ReactiveObject
     [Reactive]
     public int Bitrate { get; set; }
 
+    /// <summary>
+    /// Gets or sets whether to encode as fixed bitrate.
+    /// </summary>
+    [Reactive]
+    public bool FixedBitrate { get; set; }
+
     /// <summary>
     /// Gets or sets the encoding bits per sample for WAV or FLAC formats. Valid values are 0 (auto), 8, 16, 24 or 32.
     /// </summary>
     [Reactive]
-    public int BitsPerSample { get; set; }
+    public int BitsPerSample { get; set; } = 16;
 
     /// <summary>
     /// Gets or sets the encoding sample rate.

Common.Avalonia.App/Common.Avalonia.App.csproj

@@ -49,12 +49,5 @@
   <ItemGroup>
     <None Remove="Styles\HanumanInstituteAppIcons.otf" />
     <AvaloniaResource Include="Styles\HanumanInstituteAppIcons.otf" />
-    <AvaloniaXaml Remove="Common\AboutView.axaml" />
-    <None Include="Common\AboutView.axaml" />
-    <Compile Remove="Common\AboutView.axaml.cs" />
-    <None Include="Common\AboutView.axaml.cs">
-      <DependentUpon>AboutView.axaml</DependentUpon>
-      <SubType>Code</SubType>
-    </None>
   </ItemGroup>
 </Project>

Common.Avalonia/Converters/BooleanToBrushConverter.cs

@@ -3,7 +3,7 @@
 namespace HanumanInstitute.Common.Avalonia;
 
 /// <summary>
-/// Converts boolean values to string while allowing to configure true and false values.
+/// Converts boolean values to brush while allowing to configure true and false values.
 /// </summary>
 public sealed class BooleanToBrushConverter : BooleanConverter<Brush>
 {

Converter432Hz/ViewModels/MainViewModel.cs

@@ -45,6 +45,8 @@ public MainViewModel(ISettingsProvider<AppSettingsData> settings, IAppUpdateServ
 
         _isBitrateVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x != EncodeFormat.Flac && x != EncodeFormat.Wav)
             .ToProperty(this, x => x.IsBitrateVisible);
+        _isToggleBitrateVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Mp3)
+            .ToProperty(this, x => x.IsToggleBitrateVisible);
         _isBitsPerSampleVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Flac || x == EncodeFormat.Wav)
             .ToProperty(this, x => x.IsBitsPerSampleVisible);
         _isQualitySpeedVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Mp3 || x == EncodeFormat.Flac)
@@ -95,6 +97,12 @@ private void Bind<T1, T2>(Expression<Func<MainViewModel, T1?>> expr1, Expression
     public bool IsBitrateVisible => _isBitrateVisible.Value;
     private readonly ObservableAsPropertyHelper<bool> _isBitrateVisible;
 
+    /// <summary>
+    /// Gets or sets whether Toggle Bitrate button should be visible. 
+    /// </summary>
+    public bool IsToggleBitrateVisible => _isToggleBitrateVisible.Value;
+    private readonly ObservableAsPropertyHelper<bool> _isToggleBitrateVisible;
+
     /// <summary>
     /// Gets whether Bits Per Sample control should be visible.
     /// </summary>
@@ -256,6 +264,16 @@ private void FillSampleRateList(EncodeFormat format)
         { FileExistsAction.Rename, "Rename" },
         { FileExistsAction.Cancel, "Cancel" }
     };
+
+    /// <summary>
+    /// Enables or disables the Fixed Bitrate option.
+    /// </summary>
+    public RxCommandUnit ToggleFixedBitrate => _toggleFixedBitrate ??= ReactiveCommand.Create(ToggleFixedBitrateImpl);
+    private RxCommandUnit? _toggleFixedBitrate;
+    private void ToggleFixedBitrateImpl()
+    {
+        Settings.Encode.FixedBitrate = !Settings.Encode.FixedBitrate;
+    }
 
     /// <summary>
     /// Starts the batch encoding job.

Converter432Hz/Views/MainView.axaml

@@ -18,6 +18,7 @@
         d:DataContext="{x:Static local:ViewModelLocator.Main}" x:DataType="vm:MainViewModel">
     <Window.Resources>
         <hic:PercentageConverter x:Key="PercentageConverter" />
+        <hic:BooleanToStringConverter x:Key="BitrateConverter" TrueValue="CBR" FalseValue="VBR" />
     </Window.Resources>
     <Grid>
         <Grid Margin="10">
@@ -101,7 +102,12 @@
                         </ComboBox>
                     </Grid>
                     <Grid Margin="0,2,0,2" IsVisible="{Binding IsBitrateVisible}">
-                        <TextBlock VerticalAlignment="Center" Text="Bitrate" />
+                        <StackPanel Orientation="Horizontal">
+                            <TextBlock VerticalAlignment="Center" Text="Bitrate" />
+                            <Button Classes="round" Width="40" Margin="10,0,0,0"
+                                    Content="{Binding Settings.Encode.FixedBitrate, Converter={StaticResource BitrateConverter}}"
+                                    Command="{Binding ToggleFixedBitrate}" IsVisible="{Binding IsToggleBitrateVisible}" />
+                        </StackPanel>
                         <ComboBox HorizontalAlignment="Right" Width="120" x:CompileBindings="False"
                                   Items="{Binding BitrateList}" SelectedItem="{Binding BitrateList.CurrentItem}">
                         </ComboBox>

YangDownloader/ViewModels/EncodeSettingsViewModel.cs

@@ -27,6 +27,8 @@ public EncodeSettingsViewModel(IAudioEncoder encoder, IEnvironmentService enviro
 
         _isBitrateVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x != EncodeFormat.Flac && x != EncodeFormat.Wav)
             .ToProperty(this, x => x.IsBitrateVisible);
+        _isToggleBitrateVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Mp3)
+            .ToProperty(this, x => x.IsToggleBitrateVisible);
         _isBitsPerSampleVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Flac || x == EncodeFormat.Wav)
             .ToProperty(this, x => x.IsBitsPerSampleVisible);
         _isQualitySpeedVisible = this.WhenAnyValue(x => x.FormatsList.SelectedValue, x => x == EncodeFormat.Mp3 || x == EncodeFormat.Flac)
@@ -85,6 +87,12 @@ public bool ShiftPitch
     public bool IsBitrateVisible => _isBitrateVisible.Value;
     private readonly ObservableAsPropertyHelper<bool> _isBitrateVisible;
 
+    /// <summary>
+    /// Gets or sets whether Toggle Bitrate button should be visible. 
+    /// </summary>
+    public bool IsToggleBitrateVisible => _isToggleBitrateVisible.Value;
+    private readonly ObservableAsPropertyHelper<bool> _isToggleBitrateVisible;
+
     /// <summary>
     /// Gets whether Bits Per Sample control should be visible.
     /// </summary>
@@ -141,6 +149,16 @@ private void FillSampleRateList(EncodeFormat format)
         { 32, "32-bits" }
     };
 
+    /// <summary>
+    /// Enables or disables the Fixed Bitrate option.
+    /// </summary>
+    public RxCommandUnit ToggleFixedBitrate => _toggleFixedBitrate ??= ReactiveCommand.Create(ToggleFixedBitrateImpl);
+    private RxCommandUnit? _toggleFixedBitrate;
+    private void ToggleFixedBitrateImpl()
+    {
+        Settings.FixedBitrate = !Settings.FixedBitrate;
+    }
+
     /// <summary>
     /// Restores default settings.
     /// </summary>

YangDownloader/Views/EncodeSettingsView.axaml

@@ -4,11 +4,15 @@
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:HanumanInstitute.YangDownloader"
         xmlns:vm="clr-namespace:HanumanInstitute.YangDownloader.ViewModels"
+        xmlns:hic="clr-namespace:HanumanInstitute.Common.Avalonia;assembly=Common.Avalonia"
         mc:Ignorable="d" MinWidth="280" Width="280" MaxWidth="280" MinHeight="420" Height="420" MaxHeight="420"
         x:Class="HanumanInstitute.YangDownloader.Views.EncodeSettingsView"
         Title="Advanced Settings" Classes="gradient"
         CanResize="False" WindowStartupLocation="CenterOwner" ShowInTaskbar="False"
         d:DataContext="{x:Static local:ViewModelLocator.EncodeSettings}" x:DataType="vm:EncodeSettingsViewModel">
+    <Window.Resources>
+        <hic:BooleanToStringConverter x:Key="BitrateConverter" TrueValue="CBR" FalseValue="VBR" />
+    </Window.Resources>
     <Grid>
         <Grid Margin="10">
             <StackPanel>
@@ -19,7 +23,12 @@
                     </ComboBox>
                 </Grid>
                 <Grid Margin="0,2,0,2" Height="24" IsVisible="{Binding IsBitrateVisible}">
-                    <TextBlock VerticalAlignment="Center" Text="Bitrate" />
+                    <StackPanel Orientation="Horizontal">
+                        <TextBlock VerticalAlignment="Center" Text="Bitrate" />
+                        <Button Classes="round" Width="40" Margin="10,0,0,0"
+                                Content="{Binding Settings.FixedBitrate, Converter={StaticResource BitrateConverter}}"
+                                Command="{Binding ToggleFixedBitrate}" IsVisible="{Binding IsToggleBitrateVisible}" />
+                    </StackPanel>
                     <ComboBox HorizontalAlignment="Right" Width="110" x:CompileBindings="False"
                               Items="{Binding BitrateList}" SelectedItem="{Binding BitrateList.CurrentItem}">
                     </ComboBox>