(inserted 3/10/04)
commands I use to record video:(these are in scripts)
To record mpg or avi files I use:
ffmpegrec -Q -F $len -frequency $freq -o "$filename"
for .nuv files (large uncompressed) I use:
nuppelrec -Q -F $len -frequency $freq -o "$filename"
to record divx files live:
divx4rec -Q -F $len -frequency $freq -o "$filename
( in my experience with divx4rec, it is less stable than ffmpegrec and
produces fuzzier recordings)
$len is expressed in seconds
$freq is the megahertz frequency, I got my list from scantv.
ffmpegrec looks at the extension to establish mpg or avi file. (avi
files seem to seek better because they have an index. mpg files can be
played live (during recording) because they do
not require an index.
Now since I have multiple recordings scheduled (using
the at command ) I have developed some tricks. I don't know if
these trick are required on the current version of nvrec, but when I
did this, I needed to.
The most serious problem I had was "how do I kill a
recording process so that I may start another?"
this might not seem like much, but it actually is.
Because nvrec ( ffmpegrec or nuppelrec ) spawns multiple processes (I
think its one for vid, one for audio and one for compress.) Well if you
kill the wrong one, you can lock up the hardware and the next ffmpegrec
command fails saying that it can't access the device.
So the trick is to find the most CPU intensive process (
looking at the ps listing) and killing only that one. This
function is written into my record.pl script so that if one record job
starts as the other ends, I don't have to perfectly calculate the
number of seconds to record. I just have the later process kill the
earlier one. The changeover takes 3 to 5 seconds. So long as the clock
is correct, I don't miss the end of the first show, nor the begging of
the second.
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