[ExtractStream] Chunk 0 and 4095

[Grant Stockly]

>[3] The header chunk is full of data. We don't understand what this data 
>is for and it is not used by us. My guess would be it is used to 
>configure the MPEG decoder chip and maybe some initial start values. If 
>we are very lucky the audio skew may be in here somewhere. So this chunk 
>is valid; however, not understood.

The audio is kept in sync from time codes in the stream. I doubt there is 
any mpeg setup values, since the streams play fine without chunk 0 on the tivo.

There are two ways to save the chunk 0 (I've found that one 0 chunk is OK) 
"split --byte=131072; mv xaa header.ty; rm x*" kinda slow... or if the 
stream is already on the tivo, "./mfs_export -c 131072 <fsid> header.ty".

Looks like the split method works (every file generated is a perfect even 
131072 bytes...all 4000 of them) and they cat back together real 
quick. And if someday we understand the header, isn't it conceivable that 
we could build it from scratch? : )

My goal right now is to get a single tystream file with no more than a 
second of commercials that I can play back into the tivo or export to raw 
and synced mpg file. The time codes are still in the ty file.

>headers are a real part of the stream. A part we don't know how to use, 
but a valid part never less. The hope is one day we will be able to >use 
them, so tossing them away is not a good idea.

Whats the better idea...saving the data so that some day we can use it...or 
making the streams playable now... : ) As long as splitstream can decode 
the file, and the tivo can play it...I'm happy.