[Vorbis-dev] ogg_sync_pageout

[Ralph Giles]

On Wed, Jun 22, 2005 at 09:32:52AM -0500, Christopher Egner wrote:

> It seems to me that running ogg_sync_pageout doesn't automatically advance
> the page. This is good if you haven't worked with the given page, makes
> coding somewhat easier. However, when does a page advance. Is it after a
> call to ogg_stream_pagein?

Can you elaborate on what you mean by 'advance the page'? 
ogg_sync_pageout() fills out the pointers in the ogg_page struct to 
reference data that's been passed in and marked with ogg_sync_wrote(). I 
suppose conceptually in libogg ownership of that data passes with the 
ogg_page struct to the caller, and then back into libogg only when you 
call ogg_stream_pagein(). 

Is that what you mean? Another call to ogg_sync_pageout() could return 
another page if there's more data buffered inside the ogg_sync struct.

> Would you also need to call ogg_sync_destroy, and pretty much start over? Or
> is there a way you can feed it new data without destroying the buffer?

You don't need to call ogg_sync_destroy, you can just start feeding it 
data from the seek point and it will find the next page boundary and 
continue handing you new pages from there.

If you've passed a chain boundary you'll need to seek for the headers 
and tear down and re-initialize your decoder if they're different, of 
course.

FWIW,
 -r

> 
> Thanks a ton,
> Christopher
> 
> 
> _______________________________________________
> Vorbis-dev mailing list
> Vorbis-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/vorbis-dev