Re: [xine-devel] xine and AC3 audio format

[James Courtier-D. <Ja...@su...>]

Richard Cochran wrote:
> I'm writing an AC3 passthrough OSS driver for the Creative extigy.
> 
> I used xine to play a dvd audio track. I found that xine seems to
> write eight extra bytes when writing a frame, for example:
> 
> 00000000: 72f8 1f4e 0100 0038 770b cacf 401e fce1  r..N...8w...@...
>           |                 | |  |        |
>           +-----------------+ +--+        |
>           what is this?       syncword    frmsizecod
> 
> I supposed from reading ATSC standard, Rev. A, that the syncword
> should be the first field in a frame. What are those first eight
> bytes?
> 
> Also, xines calls write() with 6144 bytes, of which only the first
> 1800 (1792 frame size plus 8 extra) bytes seem to contain data. The
> rest of the buffer contains zeroes.
> 
> Thanks,
> Richard
> 
> 
The "what is this?" bit is something called the SPDIF header.
The AC3 frame starts at 770b
Cheers
James