[mythtv] [DOC] Re: New profile group bugs

Geoffrey Hausheer ou401cru02 at sneakemail.com
Sat Nov 1 15:43:32 EST 2003


On Sat, 01 Nov 2003 10:51:10 -0800, "Bruce Markey" said:
> If you find some spare time, you may want to write a brief
> paragraph or two for 10.5 in the HOWTO about how to configure
> profile groups. If not, I'll try to come up with something
> before the next release.
Good idea.  How is the following replacement for 10.5?  I don'r know what
cards are supported for HDTV or DVB, so I googled, and took the top
matches.  If my guesses are wrong, please update the card types and
related web-sites.

.Geoff

----------------------

10.5 Recording
Depending on your capture card, mythtv offers different video encoders. 
The following types of hardware-encoding cards are supported:
MJPEG - Zoran-based cards; see http://mjpeg.sourceforge.net
MPEG2 - iTVC15 based cards (Hauppague PVR-250/PVR-350); see
http://ivtv.sourceforce.net
HDTV - pcHDTV cards; see http://pchdtv.com
DVB - cards supporting DVB; see http://linuxtv.org

For cards without hardware encoding capabilities (all cards supported by
V4L not listed above), myth includes to methods for software encoding:
RTjpeg and MPEG4.  RTjpeg has significantly less CPU demands than MPEG4,
however it also generates larger files than MPEG4 for a given recording.

For DVB and HDTV cards, no further configuration is required after
setting up the card using the 'setup' program
For all other cards, configuration is doen through MythFrontend. 
Selecting 'Recording Profiles' from the 'TV Settings' screen will list
the profiles currently availiable for the cards in your system. 
Depending on what types of cards you have installed you may see:
(Create new profile group)
Software Encoders
Hardware MPEG Encoders
Hardware MJPEG Encoders
Trancoders

The '(Create new profile group)' will allow you to create custom profiles
in the case you have multiple backends.    Note that custom profiles are
per backend and cardtype.  If you have 2 MPEG2 encoders in a given
backend system, Creating a custom profile will effect both of them.  This
option should not be needed otherwise.

The 'Transcoders' group is a little different from the others.  Selecting
this group will result in a menu with the following options:
'RTjpeg/MPEG4' and 'MPEG2'.  These types indicate what transcoder options
will be used for a given input type (i.e. the 'MPEG2' settings would be
used to transcode MPEG2 files into MPEG4.  It does not matter if the
MPEG2 stream was created with a DVB, HDTV, or PVR-x50).  Configuration of
the options is the same as below (although any resolution settings will
be ignored)

Selecting any of the other options will show a new screen with a list of
4 profiles:
Default
Live TV
Low Quality
High Quality

The Default profile will be used for any recording which has not had a
specific profile chosen for it. The 'Live TV' profile will be used when
watching TV.  The other two profiles are for customizing in the case
you'd like more precise control over what quality is used for a given
program.

Selecting one of these profiles will allow you to adjust the relevant
options for that card.  The most relevant setting is the recorfding
resolution, but you can also choose encoding format, audio format, and
tweak other encoder specific properties as well.

NOTE: although the width and height can be changed to almost anything, if
you start MythTV and don't see video or you get "segmentation fault"
errors, it is likely that the video4linux (v4l) subsystem did not like
the height and width parameters specified. It's best to leave the default
as-is until you're sure that MythTV is operational.


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