Paul live from the volcano on VoIP phone and streaming video (video capture from screen)
Yesterday we successfully connected to Paul at the volcano using the BGAN satellite link. The following set of (five) posts will try to cover the tests we carried out, these include:
These findings made the whole trip worth while. We now know that we can connect across the world and transfer live photo, video and VoIP data to give anyone on the Internet remote access to field locations.
A video of Paul counting down from five to one on his fingers - the audio and video are quite well synchronised (1.5MB Video).(video capture from screen)
To test how the audio and video streams are performing we do a simple five-finger test. This involves counting down from five to one using your fingers. The idea behind it is simple – the audio and video streams are being run but different processes so they can lag or get out of sync – in fact we might expect this to happen as different encoding algorithms are being used to process the audio and video data. However, as you can see from the attached video they seem to be in sync, this makes conversation a lot easier. Paul’s video camera is running at half PAL (320 x 240 pixels) and 5 frames per second, with a constant bit rate of 200Kbps.
A clip showing the view point area at the top of the volcano beside a crater with venting gases (Video - 4.2MB).(video capture from screen)
Here’s a clip showing the video stream stretched to it’s limits when Paul goes walkabout with the camera. We’re using MPEG-4 video and in this clip the resolution of Paul#s camera was set to half PAL (320 x 240 pixels) with a frame rate of 5 frames per second and a constant bit rate of 200Kbps. Between key frames the MPEG-4 encoder sends the changes between consecutive frames. This means that when there is a lot of movement the image quality can drop as more information needs to be sent for each frame. In this clip we can see lots of examples where the quality drops while the camera is moving, but as Paul pauses on an object the quality of the image improves.
Live video streams at varying resolutions and frame rates. (video capture from screen)
We’ve used quite a few different video resolutions and a couple of frame rates. In all cases we’ve kept a constant bit rate of 200Kbps – Richard at callmonitor.com recommended this setting and it has served us well. Higher bit rates are probably possible, but we’re using a ‘Standard’ BGAN data link configuration (rather than one of the Streaming configurations) so we don’t really want to push our luck. The following two sets of clips show the performance we had for video at different camera settings. The first set show Paul in front of the camera with a flag, the second set show the points where we made the video link after changing the camera settings. In both cases the smoothness of the video relates to the camera’s frame rate and the clarify of the image relates to the camera’s resolution.
Photo download video clip (5.4MB) - showing the time taken to download a new thumbnail page and a new photo.
On Saturday Paul went back up to Masaya volcano for a couple of hours in the morning. Again we used the BGAN terminal to connect to the Internet. As before, we used Skype text chat throughout as our back channel for communication. The Ricoh WiFi camera worked well for taking pictures and sending them over the local WiFi network to the Asus server, where I could then access them from the UK. This time I managed to get a video of the process to show the performance of the service (see clip). The thumbnail images came down in about 11 seconds and a full picture took about 23 seconds. This is certainly usable for getting live photos from the field.
Paul doing a five finger lag test on a Skype video call using the hotel's ADSL cable connection (8.8MB mp4 video)
Yesterday Paul and I chatted on Skype using Skype’s video phone option. Here’s the video I recorded from my screen, while we did a quick five finger test. This test involves putting up your hand and holding out your fingers then closing each finger as you count down from five to none. The video gives a reasonable indication of lag.
Yesterday and today I have been testing the procedures for connecting over wired and wireless networks to live video streaming and static image transfer. Below are details of my journey starting with live video streaming over a wired network without 3G and then over 3G.
Wired Network (no 3G)
The equipment being used is a Billion wireless-N/3G ADSL Router, two Eee PC netbooks, a MacBook Pro and a an EDIMax IC-3010WG dual mode camera.