ASF format conversion

[manojrb27]

Hi all,

 

Can anyone please help me in solving the following problem in ASF. I will very much apreciate the help.

 

currently I am converting audio video payload data in ASF container format.

 

FYI - All .wmv/.wma extension files are stored in ASF container format with windows media audio & video codec encoded data. Else the files have extension .asf with other codec's payload data. ASF supports large number of audio video codecs as defined in mmreg.h

 

my basic query is regarding the audio codec specific data stored in audio stream properties object in ASF header.

ususally called as extra type specific data/ codec specific data.

 

For Windows Media Audio this data is of 10 bytes including following fields,

 

DWORD dwSamplesPerBlock; // 4bytes

WORD wEncodeOptions; // 2 bytes

DWORD dwSuperBlockAlign; // 4 bytes

 

But I didn't get what these fields should be set for. i know this is extra codec specific information followed by WAVEFORMATEX structure.

 

But this type specific data is not always 10 bytes, but it varies as the audio codec changes.

 

So can anyone please guide me in this case if I want to use g711a/g711u audio codec's payload in ASF.

what codec specific data i need to fill?

 

or can anybody point me in proper direction please to find out codec specific data ?

 

many thanks in advance,

Manoj

[manojrb27]

or does anybody have the asf file that contains g711 or other codec's payload data (except wma) ?

 

if you have can you plase send it to me at manojrb27@yahoo.com so that i can recognise the codec specific data.

 

 

would be much thankful if gets more help

 

Thanks,

Manoj