Archive for the ‘timelapse’ Category

Using an XCDAM-EX Video Camera as a Webcam

Thursday, September 20th, 2012

If you put an XDCAM-EX camera in 1080-SP mode then it generates HDV, which is 1440×1080 but with brick-like pixels and data is at Constant Bit Rate (CBR), a requirement of HDV.  For an XDCAM-EX3, there is a small iLink/Firewire connector at the back, it can be enabled/disabled by the camera’s menu.If you then run Skype, it sees the image, scales it down to Skype-format, namely 640×480 with square pixels, hence 4:3 aspect ratio.   However it does not allow for the difference in pixel shape, with the result that the image looks squashed horizontally.  A nuisance!So I wonder, is there any  interposing software that can e.g. map the pixel shapes properly or even allow some kind of zoom/pan of a (e.g.) 640×480 frame within available (e.g.) 1920×1080 (equivalent, when pixel-shape converted) image from HD or HDV camera?

  • http://www.dvinfo.net/forum/sony-xdcam-ex-cinealta/479844-need-help-doing-webcast-shoot-ex3.html
  • http://forums.creativecow.net/thread/142/864423
    • The EX in HDV mode (SP) and iLink has worked for me. I’ve done it with Telestream Wirecast (another COW forum you’ll find my floating head) for live streaming.
  • http://www.b-roll.net/forum/showthread.php?t=26269
    • Someone having difficulties, others offering advice on XDCAM-EX settings, though I’m not convinced that all of them are necessary)
  • http://www.ehow.com/how_12174693_use-hdv-camera-skype.html
    • Debut Video Recording software (free)
    • Instructions:
      • Connect the video cable plug on the USB video-capture device to the video input on the camera cable. Video cable plugs and inputs are usually color-coded yellow.
      • Plug the camera cable into the camera.
      • Plug the USB video-capture device into an open USB port on your computer.
      • Download “Debut Video Recording Software 1.42” or a later version and install the application on your computer.
      • Launch the software.
      • Click “Device” from the toolbar menu and then go to Step 7. If the software doesn’t recognize your HDV camera, click “Options.” Click the “Video Capture Device” arrow and select your camera from the list. Confirm that the “Format” and “Device” settings are correct or make changes, if needed. Click “OK” to continue.
      • Click the “Skype” icon on your computer’s taskbar and select “Open Skype.”
      • Right-click the person you want to call under “Contacts.”
      • Navigate to “Share Your Screen” and select “Share Selection.”
      • Use your mouse and drag the black box down to the inside of the video-capture software’s display area.
      • Resize the black box to fit within the display area.
      • Click on the “Start Screen Sharing” box in the upper left corner of the video display area.
      • Click “OK” in the Screen Sharing dialogue box. A “Starting Video” message will appear.
      • Wait until the person you are calling picks up. The “Screen Sharing Active” message confirms the connection
      • Read more: How to Use an HDV Camera for Skype | eHow.com http://www.ehow.com/how_12174693_use-hdv-camera-skype.html#ixzz272JXfJGR

Filming: “October Sunrise” (Timelapse 10spf)

Sunday, October 16th, 2011

A misty sunrise into a clear sky today, here from my girlfriend’s eastwards-facing rural location.  Didn’t actually point at the sun as the main thing of interest was the mist, which I wanted to see swirling and evaporating and glowing orange etc. as the sun came up.  Shot time-lapse for about 2.5 hours, this being about 1 hour 20 mins (rounded figures) before and after sunrise.

The result is at http://vimeo.com/30602784

Chose to use manual exposure, partly to emphasize magnitude of the change in lighting (auto exposure would have reduced this impression) and partly because in any case the pre-dawn shots required frame acumulation mode, hence a discontinuity when I inevitably came to switch out of that (to avoid the camera being dazzled).

In the edit (in Sony Vegas), initially straight-cut the differently-exposed clips together (in sequence).  But the result, when played, jolted uncomfortably at each cut.  Tried smoothing the levels-change, via Levels FX, but didn’t look that great.  Imagined an “Iris” effect.  Ended-up with the “Iris” transition,which gives the appearance/hint of stopping-dow, exactly as needed here.  The next “candy” item was the vignette.  Added in post (Sony Vegas) via feathered Mask.  Also some video de-noising and finally some text dissapearing into its own “mist”.

It played too quickly – all over in about 30 seconds. I wish I’d shot it one frame every second instead of every 10 seconds.  Then again I need copyright-free music of sufficient duration as background music.  I found some free 30-second-ish music slips that are free for non-profit use at http://www.royaltyfreemusic.com.  Might try stretching this (interlaced) video to (motion-compensated) double-framerate, then half-speed, some other time.  Note that Vimeo has its own Music Store for soundracks etc., some of which are free (Creative Commons license).

Rendered to H264 for uploading to Vimeo, using settings advised at http://vimeo.com/help/compression .

Camera settings:

  • Time:
    • Started filming at about 6am
    • Sunrise officially at 7:24
    • Completed filming at about 09:00
  • Constant settings:
    • Gamma STD3
      • No particular reason, just looked ok for the extremely dark pre-dawn shots.
    • HQ 1080/50i
    • Timelapse: 1 frame per 10 seconds
      • Too fast – wish I’d used 1 fps
    • WB: 6100 K
    • Gain -3dB
    • Shutter 1/60 sec
  • Exposure (manual, varied in steps)
    • For pre-dawn darkness at 06:00: f1.9, standard gamma, frame accumulation (64 frames)
    • For dawn: no frame accumulation
    • At 5 mins before sunrise: ND1 filter (1/8)
    • At 10 mins post sunrise: f3.4
    • At 25 mins post sunries: f5.1
    • At 40 mins post sunrise: ND2 filter (1/64), f3.1
  • Subsequently, searched on web to see what other people did:
    • Google: [sunrise time lapse]
      • http://www.digitaljuice.com/community_forums/tm.asp?m=121804
        • Title: “Tips on how to shoot sunrise time lapse”
        • Q: I need to shoot a sun rise time lapse. I’m trying to figure out the best way to go about it. Do I use a ND filter from the start? Do I leave in auto iris or do I have to stay by the camera making constant adjustments as the sun rises?
        • A1: Depends how long you want the shot to last. I did one the other month that went from 2 hours before sunrise to 3 hours after, no ND, auto iris. Mind you, my camera ranges from F1.9 to f16, so it managed it fairly well. Obviously the sun blew out, but not much else in the scene did, when I ended the shot, everything was exposed correctly.
        • A2: I’ve shot probably a hundred sunrises/sets. I generally shot 10-30 minutes and then shortened it to 1 frame a second. Autoexposure will work (I almost always shot this way), but you can get a nice effect going from blackness to light with a locked exposure too.