/*
* TODO: Better Implementation of bitrate determination.
* Somehow first audio stream makes the day. Then Streamnumber must
* be stored, to read the right info out of an optional stream bitrate properties
* chunk. Or if that comes first, store all the data and assign it on occurence of the
* fist audio stream.
* Where is the info about VBR
*/
public EncodingInfo Read(Stream stream)
{
EncodingInfo result = new EncodingInfo();
GUID header_guid = GUID.ReadGUID(stream);
if (!GUID.GUID_HEADER.Equals(header_guid))
{
return(result);
}
BinaryReader reader = new BinaryReader(stream);
// Skip length of header
stream.Seek(8, SeekOrigin.Current);
// Read the number of chunks.
uint chunk_count = reader.ReadUInt32();
// Skip unknown bytes
stream.Seek(2, SeekOrigin.Current);
// Two flags, When both are set, all Information needed has ben read
bool is_file_header_parsed = false;
bool is_stream_chunk_parsed = false;
// Now read the chunks
for (int i = 0; i < chunk_count && !(is_file_header_parsed && is_stream_chunk_parsed); i++)
{
long chunk_start = stream.Position;
GUID current_guid = GUID.ReadGUID(stream);
ulong chunk_len = reader.ReadUInt64();
if (GUID.GUID_FILE.Equals(current_guid))
{
stream.Seek(48, SeekOrigin.Current);
result.Duration = new TimeSpan((long)reader.ReadUInt64());
is_file_header_parsed = true;
}
else if (GUID.GUID_STREAM.Equals(current_guid))
{
GUID streamTypeGUID = GUID.ReadGUID(stream);
if (GUID.GUID_AUDIOSTREAM.Equals(streamTypeGUID))
{
// Jump over ignored values.
stream.Seek(38, SeekOrigin.Current);
result.EncodingType = GetFormatDescription(reader.ReadUInt16());
result.ChannelNumber = reader.ReadUInt16();
result.SamplingRate = (int)reader.ReadUInt32();
result.Bitrate = (int)(reader.ReadUInt32() * 8 / 1000);
is_stream_chunk_parsed = true;
}
}
stream.Seek((long)((ulong)chunk_start + chunk_len - (ulong)stream.Position), SeekOrigin.Current);
}
return(result);
}
public Tag Read(Stream stream)
{
/* Assuming we are at the start of the ASF header GUID */
GUID header_guid = GUID.ReadGUID(stream);
if (!GUID.GUID_HEADER.Equals(header_guid))
{
return(null);
}
Tag tag = new Tag();
BinaryReader reader = new BinaryReader(stream);
// Skip length of header
stream.Seek(8, SeekOrigin.Current);
// Read the number of chunks
uint chunk_count = reader.ReadUInt32();
// Skip unknown bytes
stream.Seek(2, SeekOrigin.Current);
// Two flags, When both are set, all Information needed has ben read
bool is_content_parsed = false;
bool is_extended_parsed = false;
// Now read the chunks
for (int i = 0; i < chunk_count && !(is_content_parsed && is_extended_parsed); i++)
{
long chunk_start = stream.Position;
GUID current_guid = GUID.ReadGUID(stream);
ulong chunk_len = reader.ReadUInt64();
if (GUID.GUID_CONTENTDESCRIPTION.Equals(current_guid))
{
ReadContentDescription(stream, tag);
is_content_parsed = true;
}
else if (GUID.GUID_EXTENDED_CONTENT_DESCRIPTION.Equals(current_guid))
{
ReadExtendedDescription(stream, tag);
is_extended_parsed = true;
}
stream.Seek((long)((ulong)chunk_start + chunk_len - (ulong)stream.Position), SeekOrigin.Current);
}
return(tag);
}
