Video Server Capacity Extender
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Baumann, GW: AUTHOR [+2]
Disclosed is a system of hardware and software which, when added to a video server system for delivering view-on-demand movies, increases the apparent capacity of the system through dynamic optimizing and tuning, thereby maximizing the number of movie requests satisfied and the revenue generated.
Video Server Capacity Extender
a system of hardware and software which, when
added to a video server system for delivering view-on-demand movies,
increases the apparent capacity of the system through dynamic
optimizing and tuning, thereby maximizing the number of movie
requests satisfied and the revenue generated.
In a typical
view-on-demand distribution system, multiple RAID
units are connected to multiple high speed switches, and together
they deliver data streams to set top boxes in the homes of viewers.
Where sufficient hardware is installed, the service may be true
view-on-demand, in which each viewer has a separate data stream, and
may invoke pause, high speed forward, reverse, and other common VCR
functions. Alternatively, where economics limit the hardware
investment, near view-on-demand is provided. In the latter, multiple
requests for common movie titles are aggregated and served by a
single data stream. Common VCR functions are not supported, and
pause is performed by cascading the viewer from one data stream to
another (of the same movie, with a later start time).
are limited in both capacity and bandwidth.
IBM* 9570 is a typical RAID box, with 58 GByte capacity and 60 - 70
MByte/sec bandwidth. The number of individual movie data streams
which can be supported by a single RAID is:
N[DS]= N[T] * Playing Time * (Bandwidth / Capacity)
Where N[DS]= the number of data streams which can be served from
and N[T] = the number of titles which can be stored in the RAID
In the 9570,
the maximum number of data streams is about 7
times the maximum number of titles. With movies commonly lasting
about 2 hours, start intervals of about 20 minutes would commonly be
selected for near view-on-demand access, since shorter intervals
would require multiple copies of each title, and double or triple the
technology, popular movie titles must be stored
multiple times for true view-on-demand access, consuming capacity and
limiting the number of different titles available. Moreover, demand
varies with time of day and day of week. Prior technology provides
the same function at all demand levels, and hence do not utilize
hardware capacity except during peak demand.
view-on-demand environment competes with video movie
rental. Cumulative title popularity is shown in Fig. 1. The variety
of titles being viewed at any time is shown in Fig. 2, assuming the
most popular 1,000 titles were available. The first Figure shows
that thousands of titles are necessary to satisfy a large fraction of
the demand. This reflects the current movie rental environment. The
second Figure shows that a large majority of those movies, though
viewed occasionally, will not be in use most of the time, and hence
would consume RAID capacity without generating significan...