[Abheeshta]

Hi,

I have been trying to get the Codec UL from the descriptor.

This is what I have been doing unsuccessfully:

if(Track && (Descriptor->IsA(FileDescriptor_UL)))
{
MDObjectPtr Codec_ul=Descriptor->Child("Codec");
if(Codec_ul)
ULPtr codec_ul_ptr=Codec_ul->GetUL();
//const UInt8 *this_ptr=Codec_ul->GetUL()->GetValue();
}

The MDObjectPtr never gets initialized. Help Please.

[Matt Beard]

I don't see why the MDObjectPtr Codec_ul is not getting initialized (but I would change its name as there is already a Codec_UL which is the UL of this property). Are you sure that this file descriptor has a codec property?

GetUL() will return the property UL (the same as the value of the global constant Codec_UL mentioned above) not the value of property as a UL.

I would use the following:

Code:

if(Track && (Descriptor->IsA(FileDescriptor_UL)))
{
    ULPtr CodecLabel;
    MDObjectPtr Codec = Descriptor->Child(Codec_UL);

    if(Codec)
    {
        DataChunkPtr Data = Codec->PutData();
        if(Data->Size == 16) CodecLabel = new UL(Data->Data);
    }
}

What happens here is that once the codec property is located its value is written into a buffer. This should be 16 bytes (but I always check as you never know what rubbish there may be in the file!). This can then be used to build a new UL.