Add Equalizer

libvlcsharp/Manual/Equalizer.cs

+using System;
+using System.Runtime.InteropServices;
+using System.Security;
+
+namespace VideoLAN.LibVLC.Manual
+{
+    public class Equalizer : Internal
+    {
+        struct Native
+        {
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_new")]
+            internal static extern IntPtr LibVLCAudioEqualizerNew();
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_release")]
+            internal static extern void LibVLCAudioEqualizerRelease(IntPtr equalizer);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_new_from_preset")]
+            internal static extern IntPtr LibVLCAudioEqualizerNewFromPreset(uint index);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_set_preamp")]
+            internal static extern int LibVLCAudioEqualizerSetPreamp(IntPtr equalizer, float preamp);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_preamp")]
+            internal static extern float LibVLCAudioEqualizerGetPreamp(IntPtr equalizer);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_set_amp_at_index")]
+            internal static extern int LibVLCAudioEqualizerSetAmpAtIndex(IntPtr equalizer, float amp, uint band);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_amp_at_index")]
+            internal static extern float LibVLCAudioEqualizerGetAmpAtIndex(IntPtr equalizer, uint band);
+            
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_preset_count")]
+            internal static extern uint LibVLCAudioEqualizerGetPresetCount();
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_preset_name")]
+            internal static extern IntPtr LibVLCAudioEqualizerGetPresetName(uint index);
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_band_count")]
+            internal static extern uint LibVLCAudioEqualizerGetBandCount();
+
+            [SuppressUnmanagedCodeSecurity]
+            [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl,
+                EntryPoint = "libvlc_audio_equalizer_get_band_frequency")]
+            internal static extern float LibVLCAudioEqualizerGetBandFrequency(uint index);
+        }
+
+        /// <summary>
+        /// Create a new default equalizer, with all frequency values zeroed.
+        /// The new equalizer can subsequently be applied to a media player by invoking
+        /// libvlc_media_player_set_equalizer().
+        /// version LibVLC 2.2.0 or later
+        /// </summary>
+        public Equalizer() : base(Native.LibVLCAudioEqualizerNew, Native.LibVLCAudioEqualizerRelease )
+        {
+        }
+
+        /// <summary>
+        /// Create a new equalizer, with initial frequency values copied from an existing preset.
+        /// The new equalizer can subsequently be applied to a media player by invoking
+        /// libvlc_media_player_set_equalizer().
+        /// version LibVLC 2.2.0 or later
+        /// </summary>
+        /// <param name="index">index of the preset, counting from zero</param>
+        public Equalizer(uint index) : base(() => Native.LibVLCAudioEqualizerNewFromPreset(index), Native.LibVLCAudioEqualizerRelease)
+        {
+        }
+
+        /// <summary>
+        /// Set a new pre-amplification value for an equalizer.
+        /// The new equalizer settings are subsequently applied to a media player by invoking
+        /// MediaPlayer::setEqualizer().
+        /// The supplied amplification value will be clamped to the -20.0 to +20.0 range.
+        /// </summary>
+        /// <param name="preamp">preamp value (-20.0 to 20.0 Hz)</param>
+        ///  LibVLC 2.2.0 or later
+        /// <returns>true on success, false otherwise</returns>
+        public bool SetPreamp(float preamp) => Native.LibVLCAudioEqualizerSetPreamp(NativeReference, preamp) == 0;
+
+        /// <summary>
+        /// Get the current pre-amplification value from an equalizer.
+        /// return preamp value (Hz)
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        public float Preamp => Native.LibVLCAudioEqualizerGetPreamp(NativeReference);
+
+        /// <summary>
+        /// Set a new amplification value for a particular equalizer frequency band.
+        /// The new equalizer settings are subsequently applied to a media player by invoking MediaPlayer::setEqualizer().
+        /// The supplied amplification value will be clamped to the -20.0 to +20.0 range.
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        /// <param name="amp">amplification value (-20.0 to 20.0 Hz)</param>
+        /// <param name="band">index, counting from zero, of the frequency band to set</param>
+        public bool SetAmp(float amp, uint band) =>
+            Native.LibVLCAudioEqualizerSetAmpAtIndex(NativeReference, amp, band) == 0;
+
+        /// <summary>
+        /// Get the amplification value for a particular equalizer frequency band.
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        /// <param name="band">index, counting from zero, of the frequency band to get</param>
+        /// <returns>amplification value (Hz); NaN if there is no such frequency band</returns>
+        public float Amp(uint band) => Native.LibVLCAudioEqualizerGetAmpAtIndex(NativeReference, band);
+
+        /// <summary>
+        /// Get the number of equalizer presets.
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        public uint PresetCount => Native.LibVLCAudioEqualizerGetPresetCount();
+
+        /// <summary>
+        /// Get the name of a particular equalizer preset.
+        /// This name can be used, for example, to prepare a preset label or menu in a user interface.
+        /// </summary>
+        /// <param name="index">index of the preset, counting from zero</param>
+        /// <returns>preset name, or empty string if there is no such preset</returns>
+        public string PresetName(uint index) => (string)Utf8StringMarshaler.GetInstance().MarshalNativeToManaged(Native.LibVLCAudioEqualizerGetPresetName(index));
+
+        /// <summary>
+        /// Get the number of distinct frequency bands for an equalizer.
+        /// return number of frequency bands
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        public uint BandCount => Native.LibVLCAudioEqualizerGetBandCount();
+
+        /// <summary>
+        /// Get a particular equalizer band frequency.
+        /// This value can be used, for example, to create a label for an equalizer band control in a user interface.
+        /// LibVLC 2.2.0 or later
+        /// </summary>
+        /// <param name="index">index index of the band, counting from zero</param>
+        /// <returns>equalizer band frequency (Hz), or -1 if there is no such band</returns>
+        public float BandFrequency(uint index) => Native.LibVLCAudioEqualizerGetBandFrequency(index);
+    }
+}
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