void MetaDataHandler(AtomCallbackArgs a)
{
// see https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/Metadata/Metadata.html
switch (a.TypeString)
{
case "keys":
{
var version = a.Reader.GetByte();
var flags = a.Reader.GetBytes(3);
var entryCount = a.Reader.GetUInt32();
for (int i = 1; i <= entryCount; i++)
{
var keySize = a.Reader.GetUInt32();
var keyValueSize = (int)keySize - 8;
var keyNamespace = a.Reader.GetUInt32();
var keyValue = a.Reader.GetBytes(keyValueSize);
metaDataKeys.Add(Encoding.UTF8.GetString(keyValue));
}
break;
}
case "ilst":
{
var directory = new QuickTimeMetadataHeaderDirectory();
// Iterate over the list of Metadata Item Atoms.
for (int i = 0; i < metaDataKeys.Count; i++)
{
long atomSize = a.Reader.GetUInt32();
if (atomSize < 24)
{
directory.AddError("Invalid ilist atom type");
a.Reader.Skip(atomSize - 4);
continue;
}
var atomType = a.Reader.GetUInt32();
// Indexes into the metadata item keys atom are 1-based (1…entry_count).
// atom type for each metadata item atom is the index of the key
if (atomType < 1 || atomType > metaDataKeys.Count)
{
directory.AddError("Invalid ilist atom type");
a.Reader.Skip(atomSize - 8);
continue;
}
var key = metaDataKeys[(int)atomType - 1];
// Value Atom
var typeIndicator = a.Reader.GetUInt32();
var localeIndicator = a.Reader.GetUInt32();
// Data Atom
var dataTypeIndicator = a.Reader.GetUInt32();
if (!_supportedAtomValueTypes.Contains((int)dataTypeIndicator))
{
directory.AddError($"Unsupported type indicator \"{dataTypeIndicator}\" for key \"{key}\"");
a.Reader.Skip(atomSize - 20);
continue;
}
// Currently only the Default Country/Locale is supported
var dataLocaleIndicator = a.Reader.GetUInt32();
if (dataLocaleIndicator != 0)
{
directory.AddError($"Unsupported locale indicator \"{dataLocaleIndicator}\" for key \"{key}\"");
a.Reader.Skip(atomSize - 24);
continue;
}
var data = a.Reader.GetBytes((int)atomSize - 24);
if (directory.TryGetTag(key, out int tag))
{
DecodeData(data, (int)dataTypeIndicator, tag, directory);
}
else
{
directory.AddError($"Unsupported ilist key \"{key}\"");
}
}
directories.Add(directory);
break;
}
}
}
void MetaDataHandler(AtomCallbackArgs a)
{
// see https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/Metadata/Metadata.html
switch (a.TypeString)
{
case "keys":
{
a.Reader.Skip(4); // 1 byte version, 3 bytes flags
var entryCount = a.Reader.GetUInt32();
for (int i = 1; i <= entryCount; i++)
{
var keySize = a.Reader.GetUInt32();
var keyValueSize = (int)keySize - 8;
a.Reader.Skip(4); // uint32: key namespace
var keyValue = a.Reader.GetBytes(keyValueSize);
metaDataKeys.Add(Encoding.UTF8.GetString(keyValue));
}
break;
}
case "ilst":
{
// Iterate over the list of Metadata Item Atoms.
for (int i = 0; i < metaDataKeys.Count; i++)
{
long atomSize = a.Reader.GetUInt32();
if (atomSize < 24)
{
GetMetaHeaderDirectory().AddError("Invalid ilist atom type");
a.Reader.Skip(atomSize - 4);
continue;
}
var atomType = a.Reader.GetUInt32();
// Indexes into the metadata item keys atom are 1-based (1…entry_count).
// atom type for each metadata item atom is the index of the key
if (atomType < 1 || atomType > metaDataKeys.Count)
{
GetMetaHeaderDirectory().AddError("Invalid ilist atom type");
a.Reader.Skip(atomSize - 8);
continue;
}
var key = metaDataKeys[(int)atomType - 1];
// Value Atom
a.Reader.Skip(8); // uint32 type indicator, uint32 locale indicator
// Data Atom
var dataTypeIndicator = a.Reader.GetUInt32();
if (!_supportedAtomValueTypes.Contains((int)dataTypeIndicator))
{
GetMetaHeaderDirectory().AddError($"Unsupported type indicator \"{dataTypeIndicator}\" for key \"{key}\"");
a.Reader.Skip(atomSize - 20);
continue;
}
// locale not supported yet.
a.Reader.Skip(4);
var data = a.Reader.GetBytes((int)atomSize - 24);
if (QuickTimeMetadataHeaderDirectory.TryGetTag(key, out int tag))
{
object value = dataTypeIndicator switch
{
// UTF-8
1 => new StringValue(data, Encoding.UTF8),
// BE Float32 (used for User Rating)
23 => BitConverter.ToSingle(BitConverter.IsLittleEndian ? data.Reverse().ToArray() : data, 0),
// 13 JPEG
// 14 PNG
// 27 BMP
_ => data
};
GetMetaHeaderDirectory().Set(tag, value);
}
else
{
GetMetaHeaderDirectory().AddError($"Unsupported ilist key \"{key}\"");
}
}
break;
}
}
}
