[mythtv-users] Re: Torrentocracy Patch against Mythtv-cvs

[Brad Templeton]

On Thu, Mar 03, 2005 at 03:30:46PM -0500, Joseph A. Caputo wrote:
> On Thursday 03 March 2005 14:51, Brad Templeton wrote:
> > On Thu, Mar 03, 2005 at 08:53:01AM -0800, Chris Petersen wrote:
> > > This is pretty standard -- shows are edited such that there are 
> > > commercial breaks in certain places.  However, it does NOT account 
> > > for  
> > > the commercial breaks being the same length in each region 
> > > (remember,  
> > > commercials are regional things).
> > 
> > Over time this is solved once you have enough people watching your
> > exact profile of show.   That's easy for all the cable networks,
> > everybody watches exactly the same show on Discovery Channel (even the
> > same east and west.)  I think it's also true for prime time network 
> > programming, they are all on the same tight schedule. 
> 
> No; cable providers & broadcast network affiliates can insert their own 
> ads in certain cases, AFAIK.

They can, but it is my understanding that they just play them into
the live stream, they don't change how anything else airs.  Is this
incorrect?

Syndicated shows, distributed in advance, can be edited, as can
some network shows (there have been stations who, in order to get
more commercial time, speed shows up by a few percent.)  In these
cases you would indeed have to share information only with people
who watched the same show at the same time on the same channel.

However, there are lots of cases (and I still suspect most cable
and all satellite broadcasts) where there is only one source.

The algorithm I describe, where you note changes wrt events in
the show rather than the exact time, work even then, they only
fail in the case of time stretch differing from station to station.

Note that with digital TV, such as HDTV broadcasts, you are getting
an identical byte-stream for the program in many cases, so you can
actually generate hashes of the frames to identify where you are
in the program.     Though I would use the center lines of the frame in
case a local station is adding any kind of logo or OSD by re-editing
the mpeg.  I think that's pretty rare.