mtdean at thirdcontact
Oct 25, 2006, 12:44 AM
Post #2 of 8
(4255 views)
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Re: Using mythtv and PVR-350 to capture from video camera
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On 10/24/06 21:51, Jason Surprise wrote:
>The PVR-350 has svideo and composite inputs. Is there a way to set up
>mythtv to be able to capture from these sources, and hook up my video
>camera to use the PVR-350 to convert to mpeg2?
>
Shut down mythfrontend and mythbackend. Run mythtv-setup.
In "Video Sources", create a new video source (i.e. "VCR" or "Digital
Video Camera" or "External" or whatever--just make sure you give it a
name). For the grabber, select, "No grabber." Select "Finish". Hit
Escape to go back to the menu.
In "Channels", create a new channel. Give it a name (like "VCR" or
"Camera" or "External" or ...) and a unique channel number (one that
doesn't yet exist on your system) and callsign ("VCR", "Cam", "Ext",
"Other Stuff", ...). Select the video source you just created. While
you're at it, you'll probably want to mark the channel as commercial
free (depends on your home movies, I guess :). Select "Next." Do /not/
change the "Frequency or Channel" field--it should be exactly the same
as the channel number you specified previously. Select "Finish". Hit
Escape to go back to the menu.
In "Input Connections", associate the new source to the appropriate
input. Set the "External channel change command" to "/bin/true" (no
quotes). Do /not/ fill in a value for "Preset tuner to channel", do
/not/ "Scan for channels" or "Fetch channels from listings source".
Ensure the channel you just created is selected as the starting
channel. Select "Finish". Hit Escape to go back to the menu.
Exit mythtv-setup. You'll be told to run mythfilldatabase, but--since
your new source uses "No grabber", it's unnecessary. So, start up
mythbackend and mythfrontend. Then, create manual recording schedules
to record from your camera.
What? Manual recording schedules?
Yep.
Using manual recording schedules is not ideal because it's
non-interactive (as a PVR should be). So, when creating a manual
recording, you'll be able to specify a name (which is good), but you
must specify a start time and an end time (which isn't so good).
Therefore, you have to guess the content's length and specify a
longer-than-the-content recording time to allow for starting the video
sometime after the recording starts and ensuring it ends sometime before
the recording stops.
Note, though, that if you start watching LiveTV and hit record, Myth
will create a 30-minute manual recording starting at the time you press
record. If you need to extend the recording time, you will have to exit
LiveTV and modify the end time on the in-progress recording before the
recording finishes. Also, recordings made on "channels" with no guide
data will get terrible names if recorded from LiveTV with the record
button, so manual recordings--which allow specifying names for the
recordings--are much more appropriate.
If you just "watch" LiveTV to do the recordings, Myth will in fact
record input; however, you'll encounter similar issues as with the
record button. Since you have no guide data, the recordings will have
terrible names and will be broken into 30-minute segments. I think with
LiveTV, though, the first segment breaks on the half-hour--i.e. at the
top of or half-past an hour on the clock, regardless of when you started
watching LiveTV, so the first segment will be less than 30 minutes
long. Note, also, that it's critical that you change the recording
group from LiveTV to something else if you record the video this
way--otherwise, the recording will be autoexpired "tomorrow."
So, basically, although you can do as you asked, doing so is probably
not what you want because Myth was designed as a PVR, not as an
interactive recording application. Therefore, it may actually make a
lot more sense to just find a time when a capture card isn't in use and
use "dd if=/dev/video4 of=/home/me/MySummerVacation.mpg". (This example
shows using capture card 5 because it's the least likely to be used for
recordings. If you only have 1 card, use "/dev/video0", or with 2 cards
use "/dev/video1", or ...) Note, though, that with this approach,
you'll have to run the appropriate ivtvctl commands to set the format,
resolution, and input before using dd to capture.
Something like:
ivtvctl -u 0x3000
ivtvctl -p 6
ivtvctl -f width=720,height=480
dd if=/dev/video4 of=/home/me/MySummerVacation.mpg
Should do. Submit the last command--the dd command--when you're ready
to start recording. Then, when finished, use Ctrl-C to stop the
recording (you may want to record a few seconds longer than necessary so
you can clean up the end of the recording with an MPEG editor).
Mike
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