public static ASFHeader Read(ASFChunk chunk)
{
var streams = new List <StreamType>();
int bitrate = 0;
var s = new MemoryStream(chunk.Data, false);
ASFObject.ReadHeader(s); //root_obj
var sub_headers = BinaryReader.ReadUInt32LE(s);
s.Seek(2, SeekOrigin.Current); //2 bytes padding?
for (var i = 0; i < sub_headers; i++)
{
var obj = ASFObject.Read(s);
switch (obj.Type)
{
case ASFObject.KnownType.FileProperty: {
var objdata = new MemoryStream(obj.Data, false);
objdata.Seek(32, SeekOrigin.Current);
BinaryReader.ReadInt64LE(objdata); //packets
objdata.Seek(28, SeekOrigin.Current);
BinaryReader.ReadInt32LE(objdata); //packetsize_min
BinaryReader.ReadInt32LE(objdata); //packetsize_max
bitrate = (BinaryReader.ReadInt32LE(objdata) + 999) / 1000;
}
break;
case ASFObject.KnownType.StreamProperty: {
var objdata = new MemoryStream(obj.Data, false);
var stream_type = new Guid(BinaryReader.ReadBytes(objdata, 16));
if (stream_type == ASFObject.StreamIDAudio)
{
streams.Add(StreamType.Audio);
}
else if (stream_type == ASFObject.StreamIDVideo)
{
streams.Add(StreamType.Video);
}
else
{
streams.Add(StreamType.Unknown);
}
}
break;
default:
break;
}
}
return(new ASFHeader(bitrate, streams.ToArray()));
}
public TopLevelHeaderObjectData(ReadOnlyMemory <byte> rawData)
{
RawData = rawData;
var count = BinaryPrimitives.ReadInt32LittleEndian(RawData.Span);
var mem = RawData.Slice(6);
var objects = new ASFObject[count];
for (int i = 0; i < count; i++)
{
var(obj, nxt) = ASFObject.ReadFromMemory(mem);
objects[i] = obj;
mem = nxt;
}
Objects = objects;
}