AAC Encoder Interface Reference¶

/// <summary>
/// AAC encoder configuration structure.
/// </summary>
public struct AACConfig
{
    /// <summary>
    /// AAC version/profile (typically 2 for AAC-LC, 4 for AAC-HE)
    /// </summary>
    public int version;

    /// <summary>
    /// Object type / profile:
    /// 2 = AAC-LC (Low Complexity) - recommended for most uses
    /// 5 = AAC-HE (High Efficiency)
    /// 29 = AAC-HEv2 (High Efficiency version 2)
    /// </summary>
    public int object_type;

    /// <summary>
    /// Output format type (0 = Raw AAC, 1 = ADTS)
    /// </summary>
    public int output_type;

    /// <summary>
    /// Target bitrate in bits per second (e.g., 128000 for 128 kbps)
    /// </summary>
    public int bitrate;
}

/// <summary>
/// AAC encoder runtime information.
/// </summary>
public struct AACInfo
{
    /// <summary>
    /// Input sample rate in Hz (e.g., 44100, 48000)
    /// </summary>
    public int samplerate;

    /// <summary>
    /// Number of audio channels (1 = mono, 2 = stereo, 6 = 5.1, etc.)
    /// </summary>
    public int channels;

    /// <summary>
    /// AAC frame size in samples (typically 1024 for AAC-LC)
    /// </summary>
    public int frame_size;

    /// <summary>
    /// Total number of frames encoded
    /// </summary>
    public long frames_done;
}

using System;
using System.Runtime.InteropServices;

namespace VisioForge.DirectShowAPI
{
    /// <summary>
    /// AAC encoder configuration structure.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public struct AACConfig
    {
        public int version;
        public int object_type;
        public int output_type;
        public int bitrate;
    }

    /// <summary>
    /// AAC encoder runtime information.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public struct AACInfo
    {
        public int samplerate;
        public int channels;
        public int frame_size;
        public long frames_done;
    }

    /// <summary>
    /// Monogram AAC encoder configuration interface.
    /// Provides structure-based configuration for AAC encoding.
    /// </summary>
    [ComImport]
    [Guid("B2DE30C0-1441-4451-A0CE-A914FD561D7F")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IMonogramAACEncoder
    {
        /// <summary>
        /// Gets the current AAC encoder configuration.
        /// </summary>
        /// <param name="config">Reference to AACConfig structure to receive current settings</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetConfig(ref AACConfig config);

        /// <summary>
        /// Sets the AAC encoder configuration.
        /// </summary>
        /// <param name="config">Reference to AACConfig structure containing desired settings</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetConfig(ref AACConfig config);
    }
}

using System;
using System.Runtime.InteropServices;
namespace VisioForge.DirectShowAPI
{
    /// <summary>
    /// VisioForge AAC encoder configuration interface.
    /// Provides comprehensive property-based control over AAC encoding parameters.
    /// </summary>
    [ComImport]
    [Guid("0BEF7533-39E6-42a5-863F-E087FAB5D84F")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IVFAACEncoder
    {
        /// <summary>
        /// Forces a specific input sample rate. Set to 0 to accept any rate.
        /// </summary>
        /// <param name="ulSampleRate">Sample rate in Hz (e.g., 44100, 48000). 0 = any rate</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetInputSampleRate(uint ulSampleRate);
        /// <summary>
        /// Gets the configured input sample rate.
        /// </summary>
        /// <param name="pulSampleRate">Receives sample rate in Hz. 0 if not fixed</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetInputSampleRate(out uint pulSampleRate);
        /// <summary>
        /// Sets the number of input channels.
        /// </summary>
        /// <param name="nChannels">Number of channels (1=mono, 2=stereo, 6=5.1, etc.)</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetInputChannels(short nChannels);
        /// <summary>
        /// Gets the number of input channels.
        /// </summary>
        /// <param name="pnChannels">Receives the number of channels</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetInputChannels(out short pnChannels);
        /// <summary>
        /// Sets the target bitrate. Set to -1 to use maximum bitrate.
        /// </summary>
        /// <param name="ulBitRate">Bitrate in bits per second (e.g., 128000). -1 = maximum</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetBitRate(uint ulBitRate);
        /// <summary>
        /// Gets the configured bitrate.
        /// </summary>
        /// <param name="pulBitRate">Receives bitrate in bps. -1 if set to maximum</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetBitRate(out uint pulBitRate);
        /// <summary>
        /// Sets the AAC profile type.
        /// </summary>
        /// <param name="uProfile">Profile: 2=AAC-LC, 5=AAC-HE, 29=AAC-HEv2</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetProfile(uint uProfile);
        /// <summary>
        /// Gets the current AAC profile.
        /// </summary>
        /// <param name="puProfile">Receives the profile type</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetProfile(out uint puProfile);
        /// <summary>
        /// Sets the output format.
        /// </summary>
        /// <param name="uFormat">Format: 0=Raw AAC, 1=ADTS</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetOutputFormat(uint uFormat);
        /// <summary>
        /// Gets the output format.
        /// </summary>
        /// <param name="puFormat">Receives the output format</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetOutputFormat(out uint puFormat);
        /// <summary>
        /// Sets the time shift value for timestamp adjustment.
        /// </summary>
        /// <param name="timeShift">Time shift in milliseconds</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetTimeShift(int timeShift);
        /// <summary>
        /// Gets the time shift value.
        /// </summary>
        /// <param name="ptimeShift">Receives the time shift in milliseconds</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetTimeShift(out int ptimeShift);
        /// <summary>
        /// Enables or disables Low Frequency Effects (LFE) channel.
        /// </summary>
        /// <param name="lfe">1 to enable LFE, 0 to disable</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetLFE(uint lfe);
        /// <summary>
        /// Gets the LFE channel state.
        /// </summary>
        /// <param name="p">Receives LFE state (1=enabled, 0=disabled)</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetLFE(out uint p);
        /// <summary>
        /// Enables or disables Temporal Noise Shaping (TNS).
        /// TNS improves encoding of transient sounds.
        /// </summary>
        /// <param name="tns">1 to enable TNS, 0 to disable</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetTNS(uint tns);
        /// <summary>
        /// Gets the TNS state.
        /// </summary>
        /// <param name="p">Receives TNS state (1=enabled, 0=disabled)</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetTNS(out uint p);
        /// <summary>
        /// Enables or disables Mid-Side stereo coding.
        /// Can improve compression for stereo audio.
        /// </summary>
        /// <param name="v">1 to enable mid-side coding, 0 to disable</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int SetMidSide(uint v);
        /// <summary>
        /// Gets the mid-side coding state.
        /// </summary>
        /// <param name="p">Receives mid-side state (1=enabled, 0=disabled)</param>
        /// <returns>HRESULT (0 for success)</returns>
        [PreserveSig]
        int GetMidSide(out uint p);
    }
}