[mythtv-users] am i dropping frames?

Brian Wood beww at beww.org
Tue Jan 15 03:52:28 UTC 2008

Steve Peters - Priority Electronics wrote:

>     Also, keep in mind, most recordings are just fine, but it's
>     noticable when i watch sports. Don't know why.

There are several reasons why sports programming tends to be more
vulnerable to digital artifacts:

It generally contains more "unpredictable" motion, requiring a lot more
processing power, and overflowing cheaper (ie: under $30,000) encoders.

Encoding has to be done in real time, pre-taped programming can be
processed at leisure, sometimes using multiple passes (it's not always,
but it can be).

Sports programs are transported by fiber or satellite over twice as many
paths as a program that originates at the network studio (the "backhaul"
is added). Satellite and landline fiber both process heavily.

The program might be decoded and then re-encoded at your local affiliate
(in the case of an off-air station). CBS does this in order to be able
to switch commercials at baseband. Fox, OTOH, uses a device that allows
then to insert or switch into an MPEG stream, but both methods introduce


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