/// <summary>
/// Copy field values from another <see cref="WaveFormat"/> object.
/// </summary>
/// <param name="other">The <see cref="WaveFormat"/> object to copy from.</param>
public override void CopyFrom(WaveFormat other)
{
base.CopyFrom(other);
WaveFormatEx otherEx = other as WaveFormatEx;
if (otherEx != null)
{
this.ExtraInfo = (byte[])otherEx.ExtraInfo?.Clone();
}
}
/// <summary>
/// Reads from a stream to create a WaveFormat object.
/// </summary>
/// <param name="stream">
/// The stream to read the WaveFormat from (e.g. a file). The stream should already
/// be positioned on the first byte of the WaveFormat header (i.e. the format tag).
/// Note that the stream is not disposed after the header has been read.
/// </param>
/// <param name="formatLength">
/// The total number of bytes in the stream that represent the WaveFormat header.
/// </param>
/// <returns>
/// A new WaveFormat header constructed from the stream.
/// </returns>
public static WaveFormat FromStream(Stream stream, int formatLength)
{
if (formatLength < 16)
{
throw new InvalidDataException("A WaveFormat must contain at least 16 bytes");
}
BinaryReader reader = new BinaryReader(stream);
WaveFormat waveFormat = new WaveFormat();
waveFormat.FormatTag = (WaveFormatTag)reader.ReadUInt16();
waveFormat.Channels = reader.ReadUInt16();
waveFormat.SamplesPerSec = reader.ReadUInt32();
waveFormat.AvgBytesPerSec = reader.ReadUInt32();
waveFormat.BlockAlign = reader.ReadUInt16();
waveFormat.BitsPerSample = reader.ReadUInt16();
if (formatLength > 16)
{
// Format may contain extra bytes
waveFormat.ExtraSize = reader.ReadUInt16();
// Sanity check and size limit
if (waveFormat.ExtraSize > formatLength - 18)
{
throw new FormatException("Format extra size too large");
}
if (waveFormat.ExtraSize > 0)
{
// Promote to a WaveFormatEx object to hold the extra info
waveFormat = new WaveFormatEx()
{
FormatTag = waveFormat.FormatTag,
SamplesPerSec = waveFormat.SamplesPerSec,
BitsPerSample = waveFormat.BitsPerSample,
Channels = waveFormat.Channels,
BlockAlign = waveFormat.BlockAlign,
AvgBytesPerSec = waveFormat.AvgBytesPerSec,
ExtraSize = waveFormat.ExtraSize,
// Read in the extended format extra bytes
ExtraInfo = reader.ReadBytes(waveFormat.ExtraSize)
};
}
}
return(waveFormat);
}
/// <summary>
/// Gets the appropriate Media Foundation audio media subtype from the specified wave format.
/// </summary>
/// <param name="format">
/// Input wave format to convert.
/// </param>
/// <returns>
/// Media Foundation audio subtype resulting from conversion.
/// </returns>
internal static Guid GetMediaSubtype(WaveFormat format)
{
switch (format.FormatTag)
{
case WaveFormatTag.WAVE_FORMAT_PCM:
case WaveFormatTag.WAVE_FORMAT_IEEE_FLOAT:
case WaveFormatTag.WAVE_FORMAT_DTS:
case WaveFormatTag.WAVE_FORMAT_DOLBY_AC3_SPDIF:
case WaveFormatTag.WAVE_FORMAT_DRM:
case WaveFormatTag.WAVE_FORMAT_WMAUDIO2:
case WaveFormatTag.WAVE_FORMAT_WMAUDIO3:
case WaveFormatTag.WAVE_FORMAT_WMAUDIO_LOSSLESS:
case WaveFormatTag.WAVE_FORMAT_WMASPDIF:
case WaveFormatTag.WAVE_FORMAT_WMAVOICE9:
case WaveFormatTag.WAVE_FORMAT_MPEGLAYER3:
case WaveFormatTag.WAVE_FORMAT_MPEG:
case WaveFormatTag.WAVE_FORMAT_MPEG_HEAAC:
case WaveFormatTag.WAVE_FORMAT_MPEG_ADTS_AAC:
{
// These format tags map 1-to-1 to Media Foundation formats.
// The MSDN topic http://msdn.microsoft.com/en-us/library/aa372553(VS.85).aspx indicates that
// to create an audio subtype GUID one can:
// 1. Start with the value MFAudioFormat_Base
// 2. Replace the first DWORD of this GUID with the format tag
return(new Guid((uint)format.FormatTag, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71));
}
case WaveFormatTag.WAVE_FORMAT_EXTENSIBLE:
{
WaveFormatEx formatEx = (WaveFormatEx)format;
// We only support PCM and IEEE float subtypes for extensible wave formats
if (formatEx.SubFormat == Guids.KSDataFormatSubTypePCM)
{
return(new Guid((uint)WaveFormatTag.WAVE_FORMAT_PCM, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71));
}
else if (formatEx.SubFormat == Guids.KSDataFormatSubTypeIeeeFloat)
{
return(new Guid((uint)WaveFormatTag.WAVE_FORMAT_IEEE_FLOAT, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71));
}
break;
}
}
return(Guid.Empty);
}
/// <summary>
/// Creates a copy of an existing <see cref="WaveFormat"/>.
/// </summary>
/// <param name="other">The <see cref="WaveFormat"/> to copy</param>
/// <returns>The WaveFormat object</returns>
public static WaveFormat Create(WaveFormat other)
{
if (other == null)
{
return(null);
}
WaveFormat waveFormat = null;
if (other is WaveFormatEx)
{
waveFormat = new WaveFormatEx();
}
else
{
waveFormat = new WaveFormat();
}
waveFormat.CopyFrom(other);
return(waveFormat);
}
/// <summary>
/// Indicates whether the current object is equal to another object.
/// </summary>
/// <param name="other">
/// An object to compare with this object.
/// </param>
/// <returns>
/// true if the current object is equal to the other parameter; otherwise, false.
/// </returns>
public override bool Equals(object other)
{
if (base.Equals(other))
{
// extra size is zero for both, so extra bytes are irrelevant
if (this.ExtraSize == 0)
{
return(true);
}
// Downcast other to WaveFormatEx to compare extra bytes
WaveFormatEx format = other as WaveFormatEx;
// sanity checks for extra bytes
if ((format == null) ||
(this.ExtraInfo == null) ||
(format.ExtraInfo == null) ||
(this.ExtraInfo.Length < this.ExtraSize) ||
(format.ExtraInfo.Length < format.ExtraSize))
{
return(false);
}
// byte-wise comparison of extra bytes
for (int i = 0; i < this.ExtraSize; ++i)
{
if (this.ExtraInfo[i] != format.ExtraInfo[i])
{
return(false);
}
}
// equality
return(true);
}
return(false);
}
/// <summary>
/// Marshals a <see cref="WaveFormat"/> object to a native WAVEFORMATEX structure.
/// </summary>
/// <param name="format">The <see cref="WaveFormat"/> object to marshal.</param>
/// <param name="ptr">A pointer to an unmanaged block of memory, which must be allocated before this method is called.</param>
public static void MarshalToPtr(WaveFormat format, IntPtr ptr)
{
// If format is of a derived type, demote it to the base WaveFormat to ensure
// that the base structure marshal correctly and does not overflow the allocated
// memory. The extra info bytes will be marshaled separately.
WaveFormat baseFormat = format;
if (format.GetType() != typeof(WaveFormat))
{
baseFormat = new WaveFormat();
baseFormat.CopyFrom(format);
}
Marshal.StructureToPtr(baseFormat, ptr, false);
if (format.ExtraSize > 0)
{
WaveFormatEx waveFormatEx = format as WaveFormatEx;
if ((waveFormatEx == null) ||
(waveFormatEx.ExtraInfo == null))
{
throw new InvalidOperationException("WaveFormat has non-zero extra bytes but no extra bytes field was present.");
}
if (waveFormatEx.ExtraInfo.Length < format.ExtraSize)
{
throw new InvalidOperationException($"WaveFormat extra size field and extra byte count mismatch. "
+ "Expected {format.ExtraSize} bytes but ExtraInfo only contains {waveFormatEx.ExtraInfo.Length} bytes.");
}
if (waveFormatEx != null)
{
// Write out extra info
IntPtr extraInfoPtr = new IntPtr(ptr.ToInt64() + Marshal.SizeOf <WaveFormat>());
Marshal.Copy(waveFormatEx.ExtraInfo, 0, extraInfoPtr, format.ExtraSize);
}
}
}
/// <summary>
/// Marshals a native WAVEFORMATEX structure to a <see cref="WaveFormat"/> object.
/// </summary>
/// <param name="ptr">Pointer to a WAVEFORMATEX structure.</param>
/// <returns>A <see cref="WaveFormat"/> object representing the WAVEFORMATEX structure.</returns>
public static WaveFormat MarshalFromPtr(IntPtr ptr)
{
WaveFormat waveFormat = null;
if (ptr != IntPtr.Zero)
{
waveFormat = Marshal.PtrToStructure <WaveFormat>(ptr);
if (waveFormat.ExtraSize > 0)
{
WaveFormatEx waveFormatEx = new WaveFormatEx();
waveFormatEx.CopyFrom(waveFormat);
IntPtr extraInfoPtr = new IntPtr(ptr.ToInt64() + Marshal.SizeOf <WaveFormat>());
// Read extra info
waveFormatEx.ExtraInfo = new byte[waveFormatEx.ExtraSize];
Marshal.Copy(extraInfoPtr, waveFormatEx.ExtraInfo, 0, waveFormatEx.ExtraSize);
// Return the WaveFormatEx object
waveFormat = waveFormatEx;
}
}
return(waveFormat);
}
