Two weeks ago Lars Adde defended his PhD entitled Prediction of cerebral palsy in young infants. Computer based assessment of general movements at NTNU in Trondheim. I have contributed to this research through development of the General Movement Toolbox, a variant of my Musical Gestures Toolbox. This toolbox he has used to analyse video material of children with fidgety movements, with the aim of being able to predict cerebral palsy at an early stage....
Last week we started setting up a “black box” in the new lab space. It is great to finally have a more permanent motion lab set up that we can use for various types of observation studies and recording sessions.
To allow everyone to watch their own synchronised spectrograms and motiongrams, I have made a small application called AudioVideoAnalysis. Download AudioVideoAnalysis for OS X (8MB) It currently has the following features: Draws a spectrogram from any connected microphone Draws a motiongram/videogram from any connected camera Press the escape button to toggle fullscreen mode Built with Max/MSP by Cycling ‘74 on OS X.5. I will probably make a Windows version at some point, but haven’t gotten that far yet....
I just heard a talk called “Real-Time Synaesthetic Sonification of Traveling Landscapes” (PDF) by Tim Pohle and Peter Knees from the Department of Computational Perception (great name!) in Linz. They have made an application creating music from a moving video camera. The implementation is based on grabbing a one pixel wide column from the video, plotting these columns and sonifying the image. Interestingly enough, the images they get out (see below) of this are very close to the motiongrams and videograms I have been working on....
I recently received a video file with some material I am supposed to analyse. The problem was that I couldn’t figure out what type of codec was used. VLC told me that it uses a codec called GMP4. After some research I have found that this means an MPEG-4 codec developed by GeoVision. I have found a windows version of this codec, but nothing for OS X. If anyone has any ideas, please shout out....
Looking for a solution to make flash movies on OS X, I came across this nice tutorial based on FFMPEGX. In terms of video quality I prefer to create videos with H.264 compression using MPEG Streamclip, but since flash seems to be the de facto standard on the web these days I will try to use this for an upcoming project. {#image497}
Vegard mentioned QuickTime Broadcaster in a blog entry yesterday. While QT broadcaster is certainly easy to set up and use, I have found it even easier to use some of the video broadcasting solutions in Max/MSP/Jitter. The jit.qt.broadcast object allows for QT streaming, but I have found the jit.broadcast object using RTSP to be somewhat more stable. Using Jitter also opens for all sorts of image manipulation, text overlays etc. as we are used to in the Max/MSP world....
The discussion about video standards for live processing has been summarised as: Codec: Motion.jpg (for interlaced footage) or Photo.jpg. Compression ratio/quality: Quality 80 is a decent baseline for.jpg, though you can crank as high as 97 to improve quality. Keyframes: Encode a keyframe on every frame so it’s ‘scratch-ready’. Alpha channels: For video containing alpha channels, PNG is the format of choice. Sounds like more or less the same conclusion that has been reached in the Jitter forum, when this question comes up there once in a while....
{#image381}Talking about optical illusions, here’s a bunch of them. Great that many of them are made as javascripts so that the effects can be changed. [ youtube=http://youtube.com/w/?v=_dIya1aJJKA]
Challenge Traditional keyframe displays of videos are not particularly useful when studying single-shot studio recordings of music-related movements, since they mainly show static postural information and no motion. Using motion images of various kinds helps in visualizing what is going on in the image. Below can be seen (from left): motion image, with noise reduction, with edge detection, with “trails” and added to the original image. Making Motiongrams We are used to visualizing audio with spectrograms, and have been exploring different techniques for visualizing music-related movements in a similar manner....