dvgrab starts play, but stays stuck "Waiting for DV...", no data is actually captured - how to check?
david <dv <at> 3111skyline.com>
2011-09-26 16:28:23 GMT
I am having a problem with dvgrab not downloading data to disk from my
Digital8 camera, even though dvgrab can always properly control the camera. This
problem only occurs sometimes on my first call to dvgrab. I then usually just
have to kill dvgrab, unplug/re-plug the firewire cable and start dvgrab again.
It works fine then.
The firewire connection is always seen on plug-in:
Sep 24 21:21:18 archangel kernel: [2111415.165895] firewire_core: phy config:
card 0, new root=ffc1, gap_count=5
Sep 24 21:21:18 archangel kernel: [2111415.800050] firewire_core: created device
fw1: GUID 08004601017ede99, S100
<no download - unplug/re-plug>
Sep 24 21:33:54 archangel kernel: [2112171.169381] firewire_core: phy config:
card 0, new root=ffc1, gap_count=5
Sep 24 21:33:57 archangel kernel: [2112174.926294] firewire_core: created device
fw1: GUID 08004601017ede99, S100, 1 config ROM retries
As mentioned, the camera is always found and dvgrab can ALWAYS control it
(rewind, play, etc..) The problem I'm dealing with is when dvgrab starts 'play'
to begin the capture - sometimes there is no capture, nothing recorded to disk,
even though dvgrab has started the 'play' mode on the camera just fine. I watch
the indication on the camera and play begins and the tape counter on the camera
starts increasing normally, but dvgrab is still "Waiting for DV..."
The indication I get on whether there is a successful download started is
that dvgrab issues the "Capture Started" message when download begins. For the
times when the camera is put in play mode and nothing is downloaded, dvgrab just
sits there with the "Waiting for DV..." message (even though dvgrab has rewound
the tape and started the camera playing). In either case, dvgrab will play
though the entire tape before exiting... (roughly an hour +- 5 minutes)
I am using the following command line to start dvgrab. I just echo the date
so I have a reference for when I started the download so I know to check back in
an hour to switch tapes and start it again. (the first "Capture Started" message
is mine from the CLI [poor choice of words]) The second "Capture Started"
message is the one issued by dvgrab. I run dvgrab in a subshell so that any
error messages from the dvgrab stderr stream are logged in the correct order and
don't get intertwined with any messages from the tee stderr stream (not that
I've ever had any from tee). The download/no download issue occurs regardless of
whether you run dvgrab in a subshell.
10:37 archangel:/dat_e/dv/new> (echo -e "\nCapture Started: $(date '+%b %e
%T')\n"; dvgrab -rewind -timestamp -autosplit=3600 -format raw dcrv- 2>&1) | tee
Capture Started: Sep 26 10:37:52
Found AV/C device with GUID 0x08004601017ede99
Waiting for DV...
Capture Started <== this is the dvgrab message
"dcrv-1999.12.24_17-11-33.dv": 999.98 MiB 8738 frames timecode 00:04:51.18
date 1999.12.24 17:24:26
"dcrv-1999.12.24_17-24-26.dv": 656.78 MiB 5739 frames timecode 00:08:03.05
date 1999.12.24 18:14:28
I need to find a way to test for the successful "Capture Started" from within
a BASH script to make sure I haven't started dvgrab to just waste an hour
playing the tape with nothing captured to disk. One thing I guess I could do is
to wait for 3-4 minutes after starting dvgrab and then check for the "Capture
Started" message -- but frankly, I'm unclear how I would do that from within a
script since processing in the script is waiting for dvgrab to finish?? Any
ideas on how to do this would be welcomed. I don't know, maybe start a timer in
the script before the dvgrab call that waits 5 minutes, checks for the "Capture
Started" and if not found, kills the dvgrab PID and issues an error?? I'll have
to dig more into BASH to figure that one out. Any thoughts here welcomed :)
Anybody have any idea why dvgrab would rewind and start 'play' mode and still
be stuck "Waiting for DV..." and never get to the "Capture Started" point?
David C. Rankin, J.D., P.E.
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