3. The Project The Simulcast Computer accepts video output from a presenter’s laptop and then displays the output on a touch screen. The presenter is allowed to make pen annotations onto the screen, which are then sent to the projector. The slides from the presenter, the annotations and the audio are recorded as a video and can be uploaded to our web system. Students can access the recorded lectures on our web system and add their own notes to that lecture. 3 simulcastlectures.com
4. User Interface Software & Technology Conference, Oct. 2 – 7, New York 4 simulcastlectures.com
5. Streaming Architecture Use x264 to encode video from GStreamer Send output of x264 to RTP packetizer, which is sent locally to Darwin Streaming Server (DSS) DSS restreams RTP to RTSP, which is then sent over the network Clients connect to the RTSP stream using Quicktime, which is installed on most PCs Alternatively, use Wowza or Erlyvideo to restream RTSP to RTMP (flash) Third alternative, use librtmp to stream directly to RTMP (probably needs GStreamer plugin) 5 simulcastlectures.com
6. OS Choice We originally chose Linux because of cost Windows licences cost ~$150 per machine We are now moving to Windows because of better driver support for new and innovative hardware Linux support remains a secondary priority for future deployment options Software architecture should be flexible enough to support both OSes 6 simulcastlectures.com
7. PCI based VGA capture card This is currently used in the main Simulcast Computer Excellent quality Good resolution and framerate: ~30 FPS at 1024x768 Kind of expensive at ~$400 for cheaper cards Is limited by bandwidth of PCI bus Pcamway HDVCC-01 7 simulcastlectures.com
8. PCIe based HDMI capture card The best capture card to get would likely be the Blackmagic Design Intensity Pro ($200), which has drivers that support DirectShow Captures max 1080p24 or 720p59.94 Connects via a PCIe x1 slot Blackmagic Design Intensity Pro Lenkeng LKV351 8 simulcastlectures.com
9. Fitting capture card to existing limitations and competitors Most projectors in use have a maximum resolution of 1024x768, so we should aim for a capture resolution of about that The existing podcast system captures video at 640x480 and less than 2 FPS This does not allow for fluid video or pen annotations We are aiming for resolution of 1024x768 at 30 FPS, which allows video to be used 9 simulcastlectures.com
13. GTK+ easy to make something standardized restrictive difficult to apply custom styles 13 simulcastlectures.com
14. emphasis on visuals able to animate UI elements able to customize how the UI appears using CSS style-sheets excellent performance 14 simulcastlectures.com
44. Current Work Features planning Development of demo for note capture In-class demo on 25 students, to collect data Implementation of the demo as a Moodle activity plugin 44 simulcastlectures.com
45. Note-Capture Demo Client-side JavaScript to capture students’ notes on a per-line basis Ajax transmission of timestamped notes to MySQL database 45 simulcastlectures.com
47. In-Class Demo Note-capture demo was tested during a TIES lecture 25 students participated The demo showed multiple flaws with the current note-capture system 47 simulcastlectures.com
49. Moodle Plugin The video and note-capture system was recreated as a Moodle activity plugin Additional improvements on the note-capture system 49 simulcastlectures.com
