[MPlayer-dev-eng] container format

michael c mrcole20 at hotmail.com
Thu Feb 6 19:05:52 CET 2003


Hi,

one thing that came to mind when it comes to error resilience: How about 
"rotating" the data by 90 degrees, the way I think it is done in asf and 
rm(?) too. This way, errors would not so easily appear in a row (after 
rotating it back), which I suppose codecs would handle worse than if the 
errors are spread more widely.

I also think that compression should be used for the index, but it seems 
impractical (IMHO) using it for the other headers, because that might make 
them more sensitive to errors. I could be wrong though, especially if they 
are repeated often...

What you could also think about is error correction, using reed-solomon or 
similar algorithms. It has the advantage, that you do not necessarily need 
to re-download parts, and you can easily choose how much error correction 
you want (and this way how much space it will take). I'm talking about this 
taking between 1 and 10 per cent of the space or so (adjustable, depending 
on how much you would want), just to give you an idea.
Of course, this takes quite a bit of math (and work) to implement though, 
and one might argue whether such data really belongs into a container 
format. Maybe the error correction data could be put into a seperate stream 
or something. Since this error correction is block-based though, you would 
have to think about where a block starts and ends i suppose. well, this is 
only an idea :-) It would be the 'ultimate' error checking and correction 
though.

mike

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