[mythtv-users] Freevo, Tivo & MythTV

[Marco Nelissen]

>
>> That is true for all apps in my case, since my capture cards capture
>> the over-the-air mpeg2 stream. There is no "direct-to-display" option
>> here. In any case, it only takes a fraction of a second (about 1/30 of
>> a second on average in the US ;) to decode a frame, so that shouldn't
>> be an issue at all.
>
>You are confusing analog TV signals with digital (mpeg2) ones.

I'm pretty sure I'm not... ;)

> A frame in
>the context of an mpeg stream is a frame that has a complete field - from
>that frame (keyframe) until the next keyframe, only the differences are
>transmitted. This means that if you start displaying just AFTER a
>keyframe, you will get a ghostly outline moving about the screen gradually
>painting the background as movement (assuming there is any) reveals it.
>You will only get a complete picture on a keyframe - and that may be 2, 3
>or 4 seconds down the line.

Sure, *IF* there is only a keyframe every so often. However, given that
I can switch channels AND get a good picture when using my TV's built
in tuner, and also with mplayer using the tuners in my mythtv box, all
being fed the same signal, I can say with confidence that keyframes
occur much more often than every 2, 3 or 4 seconds.