[mythtv] Compression and Gatos support

Matt Zimmerman mythtv-dev@snowman.net
Sun, 22 Dec 2002 21:59:19 -0500

On Sun, Dec 22, 2002 at 09:41:47PM -0500, Lego Andy wrote:

> I did. And I actually found several mails from you saying that it
> works for you, but no actual description on how you got it to work.

I explained exactly what is possible and what is not, and I'm fairly certain
that I did not say that capturing using mythtv works for me, because it
doesn't for reasons I have explained in previous emails.

The km capture device is limited in these important ways:

- it requires that a program like avview be running in order to provide the
  data to be captured

- you cannot use Xv (hardware scaling) at the same time

- capture cannot use the mmap interface

The second two restrictions could be addressed in software to some extent,
with various tradeoffs, but nobody has done it.

> This is ok, since I use bttv for recording and it seems to be working
> fine. So, this is my experience so far:
> 1. bttv works fine, I can record shows.. Futurama was missing first
>    couple of minutes, but my friend informed me that shows tend to
>    start couple of minutes earlier. I guess that could be fixed by
>    setting system clock. Or maybe mythtv should always record extra
>    time if two shows do not overlay.

bttv is an entirely different driver, for bt8x8 capture cards.  It has
nothing to do with the AIW card or gatos.

> 2. When I try using AIW (gatos driver km_drv), which registers device
>    /dev/video0, I get the following error(?) on console:
> VIDOCGMBUF:: Invalid argument
> VIDIOCSAUDIO: Invalid argument

This will not work, as explained above.

 - mdz