[vlc-devel] Re: Trick mode support for MPEG2 TS

Robert Scheffler Bob at pricom.com
Sat Mar 4 03:24:56 CET 2006

At any point, we can take this off-line to not confuse the topics...

For a large installation, say 5K - 10K streams, most of the popular content
is the same, say 100 movies (~200 GB) with many people watching each. Those
popular titles are fully loaded into DRAM (up to 1TB of DRAM). The less
popular content is streamed from RAID through the RAM to the client. The
tick modes are handled in hardware (FPGA) so that all the PTS/DTS and PCR
are regenerated with low jitter, the end result is very good video quality.

It comes down to deployment size. There is a cross-over point where there
are more streams than content objects, and where the active titles are much
lower than the stream count. The cross-over point seems to be about 500
streams in the US cable market today. Some of the Broadbus deployments are
in the 10K stream size. For such a deployment to use RAID, you would need
10-20 racks full of servers, or one rack with RAM and enough RAID to hold
the library.

The bottom line is when you have to buy added storage capacity to gain
streaming throughput, you loose because you need to replicate the content
objects to reach all the streams. Sure you can pile up hard drives to get
the throughput, but at a point, just loading all the movies into DRAM is
actually cheaper than all those drives. Not to mention more reliable to


Bob Scheffler

-----Original Message-----
 I don't quite understand.  The systems I've ever dealt with had 100 GB
or more of videos, all random access to the clients.  How do you
"stream from RAM" in such a context?

Måns Rullgård
mru at inprovide.com

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