|
public static FromFormatChunk ( |
||
| br | Binary reader | |
| formatChunkLength | int | Format chunk length |
| return | ||
/// <summary>
/// Reads the header part of a WAV file from a stream
/// </summary>
/// <param name="stream">The stream, positioned at the start of audio data</param>
/// <param name="format">The format found</param>
/// <param name="dataChunkPosition">The position of the data chunk</param>
/// <param name="dataChunkLength">The length of the data chunk</param>
/// <param name="chunks">Additional chunks found</param>
public static void ReadWaveHeader(Stream stream, out WaveFormat format, out long dataChunkPosition, out int dataChunkLength, List <RiffChunk> chunks)
{
dataChunkPosition = -1;
format = null;
BinaryReader br = new BinaryReader(stream);
if (br.ReadInt32() != WaveInterop.mmioStringToFOURCC("RIFF", 0))
{
throw new FormatException("Not a WAVE file - no RIFF header");
}
uint fileSize = br.ReadUInt32(); // read the file size (minus 8 bytes)
if (br.ReadInt32() != WaveInterop.mmioStringToFOURCC("WAVE", 0))
{
throw new FormatException("Not a WAVE file - no WAVE header");
}
int dataChunkID = WaveInterop.mmioStringToFOURCC("data", 0);
int formatChunkId = WaveInterop.mmioStringToFOURCC("fmt ", 0);
dataChunkLength = 0;
// sometimes a file has more data than is specified after the RIFF header
long stopPosition = Math.Min(fileSize + 8, stream.Length);
// this -8 is so we can be sure that there are at least 8 bytes for a chunk id and length
while (stream.Position <= stopPosition - 8)
{
Int32 chunkIdentifier = br.ReadInt32();
Int32 chunkLength = br.ReadInt32();
if (chunkIdentifier == dataChunkID)
{
dataChunkPosition = stream.Position;
dataChunkLength = chunkLength;
stream.Position += chunkLength;
}
else if (chunkIdentifier == formatChunkId)
{
format = WaveFormat.FromFormatChunk(br, chunkLength);
}
else
{
if (chunks != null)
{
chunks.Add(new RiffChunk(chunkIdentifier, chunkLength, stream.Position));
}
stream.Position += chunkLength;
}
}
if (format == null)
{
throw new FormatException("Invalid WAV file - No fmt chunk found");
}
if (dataChunkPosition == -1)
{
throw new FormatException("Invalid WAV file - No data chunk found");
}
}
/// <summary>
/// Reads the header part of a WAV file from a stream
/// </summary>
/// <param name="stream">The stream, positioned at the start of audio data</param>
/// <param name="format">The format found</param>
/// <param name="dataChunkPosition">The position of the data chunk</param>
/// <param name="dataChunkLength">The length of the data chunk</param>
/// <param name="chunks">Additional chunks found</param>
public static void ReadWaveHeader(Stream stream, out WaveFormat format, out long dataChunkPosition, out int dataChunkLength, List <RiffChunk> chunks)
{
dataChunkPosition = -1;
format = null;
BinaryReader br = new BinaryReader(stream);
if (br.ReadInt32() != WaveInterop.mmioStringToFOURCC("RIFF", 0))
{
throw new FormatException("Not a WAVE file - no RIFF header");
}
uint fileSize = br.ReadUInt32(); // read the file size (minus 8 bytes)
if (br.ReadInt32() != WaveInterop.mmioStringToFOURCC("WAVE", 0))
{
throw new FormatException("Not a WAVE file - no WAVE header");
}
int dataChunkID = WaveInterop.mmioStringToFOURCC("data", 0);
int formatChunkId = WaveInterop.mmioStringToFOURCC("fmt ", 0);
dataChunkLength = 0;
// sometimes a file has more data than is specified after the RIFF header
long stopPosition = Math.Min(fileSize + 8, stream.Length);
// this -8 is so we can be sure that there are at least 8 bytes for a chunk id and length
while (stream.Position <= stopPosition - 8)
{
Int32 chunkIdentifier = br.ReadInt32();
Int32 chunkLength = br.ReadInt32();
if (chunkIdentifier == dataChunkID)
{
dataChunkPosition = stream.Position;
dataChunkLength = chunkLength;
stream.Position += chunkLength;
}
else if (chunkIdentifier == formatChunkId)
{
format = WaveFormat.FromFormatChunk(br, chunkLength);
}
else
{
// check for invalid chunk length
if (chunkLength < 0 || chunkLength > stream.Length - stream.Position)
{
Debug.Assert(false, String.Format("Invalid chunk length {0}, pos: {1}. length: {2}",
chunkLength, stream.Position, stream.Length));
// an exception will be thrown further down if we haven't got a format and data chunk yet,
// otherwise we will tolerate this file despite it having corrupt data at the end
break;
}
if (chunks != null)
{
chunks.Add(new RiffChunk(chunkIdentifier, chunkLength, stream.Position));
}
stream.Position += chunkLength;
}
}
if (format == null)
{
throw new FormatException("Invalid WAV file - No fmt chunk found");
}
if (dataChunkPosition == -1)
{
throw new FormatException("Invalid WAV file - No data chunk found");
}
}
