[mythtv] [Draft] Filter documentation.

[Robert Kulagowski]

I'm incorporating Bruce's draft into the HOWTO right now.

In this section: (talking about recording filters)

"These may be used when encoding in software but do not apply when using 
a capture card with hardware encoding such as those supported by the 
ivtv driver, like the Hauppauge PVR-x50 series. "

Does this apply to all hardware-based encoders, such as the MJPEG cards, 
the DVB cards, the HDTV card, etc?