Matterhorn 2014 Unconference: Ideas for automated post-recording video handling

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This presentation proposes ideas and projects for improving quality, reducing cost and maximising flexibility by processing one or more video streams after recording. Ideas include: …

This presentation proposes ideas and projects for improving quality, reducing cost and maximising flexibility by processing one or more video streams after recording. Ideas include:

1. Using several fixed cameras as an alternative to more expensive tracking PTZ cameras, using virtual panning or mixing on multiple recorded videos to produce a single video focused on the lecturer or region of interest

2. Adjusting for more consistent brightness, contrast and colour

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  • 1. Matterhorn Unconference 2014 Let’s fix it in post! Ideas for automated post-recording video handling Stephen Marquard University of Cape Town 19 March 2014
  • 2. Why post-process video? A different approach to solving the blackboard challenge Improve video quality Close-ups More natural perspectives Avoid challenging lighting conditions (e.g. projection) Smooth motion (perfect knowledge of the future) Adjust for optimal colour / white balance / contrast Cost Multiple fixed HD IP cameras for half the cost of a PTZ camera / solution
  • 3. Cost + + < Bosch Dinion HD832 IP camera Vaddio ClearVIEW HD-USB IP camera
  • 4. The blackboard challenge How to get useful video where blackboard writing and diagrams are legible in large, wide venues
  • 5. Avoid sightline problems
  • 6. A real-time blackboard solution LectureSight: Direct a PTZ camera to follow the presenter, using real-time image analysis from an overview camera. https://opencast.jira.com/wi ki/display/LECTURESIGHT /LectureSight+Project+Ho me
  • 7. A post-processing presenter solution http://wiki.teltek.es/display/GaliTracker/GaliTracker+Home GaliTracker does cropping and zooming from a fixed HD image to give a presenter closeup
  • 8. Multiple fixed cameras 1
  • 9. Multiple fixed cameras 2
  • 10. Multiple fixed cameras 3
  • 11. Post-processing The capture agent records multiple camera streams (probably IP cameras): the mediapackage has 2, 3 or 4 presenter videos rather than 1. The camera streams are then post-processed to create a single presenter video (perhaps on the CA itself) Approaches: 1. Virtual panning (combine and crop) 2. Mixing (source selection)
  • 12. Virtual panning Left camera frame Centre camera frame Right camera frame Single panoramic image constructed from 3 fixed camera images Wide frame is cropped to position the presenter optimally (two-pass approach) Pros: smooth motion, optimal view. Cons: stitching images may be tricky, shifting perspectives.
  • 13. Mixing from multiple sources Image analysis and two-pass approach to select transition points between cameras (switch or cross-fade). Left camera Centre camera Right camera Selected camera
  • 14. Other post-processing ideas Improve colour, white balance and contrast dynamically or per region in the image. Compensate for the effect of projector image in the frame, and poor presenter lighting.
  • 15. Other post-processing ideas Improve image perspective and geometry Correct for fishbowl and other disturbing lens and camera positioning artefacts
  • 16. What next? • Get involved! Good project topics for students. • Share your ideas and possible contributions on the Matterhorn list(s).