[jitter] buffer live video up to 30 minutes

On 17-jan-2008, at 19:41, charles wrote:
> Only I want it to buffer / delay up to 30 minutes... is this  
> possible ?
> What do I need to do so that it doesnt freez after about a coupple  
> of minutes.
> I have 2Gig of RAM in my computer. Would it work if I had more ?

when you use jit.matrixset to buffer the video, it is uncompressed.
when you would use a ram disk, and record to it and read from it, you  
may compress the video
(provided that you have the CPU power to spare).
using a ram disk instead of a hard drive eliminates latency problems  
that you mey get when reading and writing simultaneously to the same  
drive.
As you cannot read and write from one file at the same time, you have  
to split the file in chunks smalelr than 30 minutes.
this introduces some file name bookkeeping, but is not hard to do.
instead of using a ram disk, go for a solid state disk (if you have  
the $$ to burn)

It helps to make two separate processes, one for recording, one for  
playback, to use multi-core CPUS.
you can achieve this with max by building a standalone for one of the  
two processes, and using max for the other
When on windows, you may use an application like WinDV to do your  
recording. it will split the files for you and number them.

We used a winDV based patch for a 10 minute delay of a DV quality  
stream.
the playback was not linear. we recorded two minute chunks to ram  
disk, and right after recording copied the chunk to a hard drive.  
just before playback the chunk was copied back to RAM disk and played  
from there.
the hard drive was there for its storage capacity, the ram disk was  
there for smoothing the stream.
worked reliably, with no dropped frames.

HtH
-jennek