I have an HD-3000 combined frontend/backend system recording OTA
broadcasts. I'm trying to set things up to automatically transcode
certain shows to save hard drive space. I've read the Myth docs:
http://www.mythtv.org/docs/mythtv-HOWTO-10.html#ss10.5
http://www.mythtv.org/docs/mythtv-HOWTO-21.html#ss21.13
but I still have some questions.
In my "Recording Profiles" menu, I have the following options:
Hardware HDTV
Default
Live TV
High Quality
Low Quality
Transcoders
From RTjpeg/MPEG4
From MPEG2
All 6 of these sub-options have essentially the same flow:
Resolution (default 480x480)
Video Codec (MP4, RTjpeg)
Codec parameters (2200kbps, etc.)
Audio Codec (MP3 or uncompressed)
Codec parameters (32kHz, 44.1kHz, 48kHz)
Volume, etc.
This is what I tried:
- I set up a recording to use the "Low Quality" recording
profile, with commercial flagging disabled, and to
automaticalliy transcode.
- I configured "Low Quality" with MPEG4 at 1100kbps with
uncompressed audio.
The result for a 1920x1080i HD broadcast was a recording of 6GB
(usually they are about 7.2GB). This looks more like 2200kbps, scaled
up from 640x480, and nowhere near the 1100kbps that I had configured
into "Low Quality".
I think what happened is that the "Hardware HDTV" profile is
completely ignored since there is no real encoding to be done for
HDTV. Then, since the HDTV stream is already in MPEG2 (or
RTjpeg/MPEG4, it doesn't matter for my reasoning), Myth just picks the
"Transcoders" profile corresponding to the format of the HDTV stream
and uses those parameters (which are still at their default 2200kbps
values).
If my reasoning is correct, does that mean an HD-3000-only system
cannot transcode different shows at different qualities, and that the
recording profiles set up in that show's recording schedule is
basically ignored (only the global "Transcoders" profiles are
available, which is selected based on what is in the HDTV stream)?
I found this threads that looks somewhat related to what I'm trying to
do, but it's pretty old, and I can't extract sufficient meaning out of
it:
http://www.gossamer-threads.com/lists/mythtv/dev/112818
How am I supposed to fit all this together? How exactly are the
"Hardware HDTV" and "Transcoders" recording profiles used? I have a
feeling the docs are biased towards hardware encoders (e.g., PVR-x50
cards) ...
Thanks,
--Rob
_______________________________________________
mythtv-users mailing list
[email protected]
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
