[mythtv-users] Using firewire input and channel changing on SA3250

[Yeechang Lee]

Dan Gapinski <ashembers at sbcglobal.net> says:
> I found a few things about using the SA3250 that I
> thought I might share, since I have not seen much buzz
> on these boxes. =

[...]

> 3) I don't know if it's the same way with Myth, but
> when I use CapDVHS to capture video over firewire, the
> resultant MPEG2 file is 700+MB for 6.5 minutes! I
> figure that can't be right - Myth can do better right?

To paraphrase Gertrude Stein, "MPEG2 is MPEG2 is MPEG2 is MPEG2." HD
cable boxes send out over their FireWire outputs the exact MPEG2 feed
the boxes get; same with HD capture cards like the HD3000 and
HD5000. All CapDVHS, MythTV, or any other software that can use the
feeds does is decompress and decode it for playback. Let me repeat:
Nothing on the computer side does any "compression" or "encoding"
whatsoever with MPEG2. (It is possible to reencode the MPEG2 feeds to
smaller files, and MythTV can help, but that's completely separate
from capturing the initial feed from the cable box or antenna.)

"700MB+ for 6.5 minutes" is accurate; see
<URL:http://www.mail-archive.com/mythtv-users@mythtv.org/msg55101.html>.

Moral of the story: To paraphrase Mr. McGuire of _The Graduate_, "I
want to say two words to you. Just two words . . . Disk space." And
lots of it.

-- 
Yeechang Lee <ylee at pobox.com> | +1 650 776 7763 | San Francisco CA US