[Mp4-tech] [video][audio] asf muxing problems

[Ivan Dokmanic]

In addition, when I try to dump contents of my asf file in graphedit 
(using wm asf reader and dump filter), resulting file is empty, but if I 
try to dump some others files, I get some result. Is that because my asf 
file doesn't conform to standard (I'm rather sure it does, despite the 
fact it's not perfect).
Thanks,
Ivan.
Ivan Dokmanic wrote:
> Hello,
>
> I'm trying to write an ASF muxer, and have some questions.
>
> 1) When muxing VC-1 advanced profile video, what should I put in 
> format extradata in stream properties (below BITMAPINFOHEADER 
> structure). It seems that (in sample videos) VC-1 sequence header 
> followed by entry point header should go there, but there are also 
> some additional bytes (namely, the first one in VC-1 AP videos I 
> checked out). Are there any special
> notes that I should take into account? It seems that all files have 
> packets with some padding, even though I don't find that necessary 
> when reading asf specs.
>
> 2) I muxed MPEG audio and VLC media player plays it without problems. 
> WMP doesn't want to play it. It doesn't play in graphedit either 
> although I tried various (proper) combinations of filters. Why would 
> that happen?
>
> 3) What should I put in extradata (type specific data) for formats 
> like AAC, AC3 (is there some info on the web - I can't find much useful)?
>
> Thanks plenty,
> Ivan Dokmanic.