How to get VC1 private data?

How to get VC1 private data?


I'm using IPP VC1 encoder and need to know how to get VC1 private data?

As far as I know, VC1 has private data that needs to be saved to Video Info structure when encoding. The private data is required to properly decoder later.

Microsoft VC1 DMO encoder provides private data, and Intel IPP VC1 encoder seems does not provide a method to retrieve the private data. So I need to know how to get private data from Intel IPP VC1 encoder?


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Hi Richard,IPP's VC-1 decoder ignores codec private data on all layers - sequence, entry-point and frame. So, there is no way to retrieve private data from stream.Regards,Sergey


Hi Sergey,

This question is actually for IPP VC1 Encoder, I need to know how to get private data from IPP VC1 Encoder.

Currently, I saved VC1 encoded frame to avi file. The avi file is not playable in MSFT Player or Media Player Classic. Both player probably use system default MSFT VC1 deocder to decode the frame.

I think the reason for above problem is that I don't have private data at the end of VIDEOINFOHEADER structure. And MSFT decoder expects private data to work properly.


Hi Richard,
Sorry for late responce, but it may be useful for others. The codec private data for DMO decoders is depends of profile is used in encoding for Simple and Main profiles it should be STRUCT_C and STRUCT_B, no header required. For Advanced profile firts byte should be ASF binding byte after Sequence header followed by Entrypoint header with startcodes.
More information you can find in SMPTE s421M and ASF Format Specification documentation.


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