/// <summary>
/// Constructs and initializes a new instance of
/// <see
/// cref="AviHeaderList" />
/// by reading the contents of a raw
/// RIFF list from a specified position in a
/// <see
/// cref="TagLib.File" />
/// .
/// </summary>
/// <param name="file">
/// A <see cref="TagLib.File" /> object containing the file
/// from which the contents of the new instance is to be
/// read.
/// </param>
/// <param name="position">
/// A <see cref="long" /> value specify at what position to
/// read the list.
/// </param>
/// <param name="length">
/// A <see cref="int" /> value specifying the number of bytes
/// to read.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="file" /> is <see langword="null" />.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="position" /> is less than zero or greater
/// than the size of the file.
/// </exception>
/// <exception cref="CorruptFileException">
/// The list does not contain an AVI header or the AVI header
/// is the wrong length.
/// </exception>
public AviHeaderList(TagLib.File file, long position,
int length)
{
if (file == null)
{
throw new ArgumentNullException(nameof(file));
}
if (length < 0)
{
throw new ArgumentOutOfRangeException(
nameof(length));
}
if (position < 0 || position > file.Length - length)
{
throw new ArgumentOutOfRangeException(
nameof(position));
}
var list = new List(file, position, length);
if (!list.ContainsKey("avih"))
{
throw new CorruptFileException(
"Avi header not found.");
}
var header_data = list["avih"][0];
if (header_data.Count != 0x38)
{
throw new CorruptFileException(
"Invalid header length.");
}
Header = new AviHeader(header_data, 0);
foreach (var list_data in list["LIST"])
{
if (list_data.StartsWith("strl"))
{
codecs.Add(AviStream
.ParseStreamList(list_data)
.Codec);
}
}
}
/// <summary>
/// Parses a raw AVI stream list and returns the stream
/// information.
/// </summary>
/// <param name="data">
/// A <see cref="ByteVector" /> object containing raw stream
/// list.
/// </param>
/// <returns>
/// A <see cref="AviStream" /> object containing stream
/// information.
/// </returns>
public static AviStream ParseStreamList(ByteVector data)
{
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
if (!data.StartsWith("strl"))
{
return(null);
}
AviStream stream = null;
var pos = 4;
while (pos + 8 < data.Count)
{
var id = data.Mid(pos, 4);
var block_length = (int)data.Mid(pos + 4, 4)
.ToUInt(false);
if (id == "strh" && stream == null)
{
var stream_header =
new AviStreamHeader(data, pos + 8);
if (stream_header.Type == "vids")
{
stream = new AviVideoStream(
stream_header);
}
else if (stream_header.Type == "auds")
{
stream = new AviAudioStream(
stream_header);
}
}
else if (stream != null)
{
stream.ParseItem(id, data, pos + 8, block_length);
}
pos += block_length + 8;
}
return(stream);
}
