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amiaopensource
Parallel Captures
I'm currently running a lab that captures two video tapes in parallel on the same computer using Media Express. Black Magic will tell you that it isn't possible to run two instances at once, but I do it every day. I would much rather be using vrecord, but I don't know if this functionality exists for the program yet. Since its possible in Media Express, it should be possible for vrecord, right?
Hey Chris, thanks for bringing this up. Currently in vrecord, it only uses the first Blackmagic device seen, see https://github.com/amiaopensource/vrecord/blob/8c29bc5005c36b64bb14a5fd575111fc90c9d138/vrecord#L148-L160. To support more than one input at once, the input device list would just have to be used to create a dropdown list in the vrecord preference window so another device could be selected. So definitely possible. Do you notice any disadvantage or risk with doing two captures in media express on your computer?
I have digitized around 100 tapes this way and haven't noticed anything. I could make a QCTools report on a few videos and upload them if you want to check. I wouldn't know what to look for, really.
Ya Media Express doesn't give the most verbose feedback. In this without verbose logging, the capture consistency could be tested by capturing a high quality digital tape multiple times (like a Betacam SX or Digibeta) and then comparing the framemd5s of the captures, which should show if one resulting file is missing frames that another one has. At any rate, such testing doesn't block adding an ability to select an input device if more than one are seen, but given the buffer overrun errors in other open issues, I'd like to find a way to diagnose issues of asking too much of the computer while recording.
Sadly, I don't think I have the ability to do that kind of test right now. If we do have Digibeta or Betacam SX, it hasn't been processed and is sitting somewhere in the stacks here on site, or out at our warehouse. If I can help come up with or test out any diagnosis method you devise, please let me know.
What do you get for:
/usr/local/opt/ffmpegdecklink/bin/ffmpeg-dl -f decklink -list_devices 1 -i dummy
when you have more than one device attached.
Sorry I missed this, I'll have to let you know on Tuesday when I come back in