What is the quality of the streaming video content?
Alexander Street offers video and audio streaming at three different bitrates.
Alexander Street now use JWPlayer which automatically determines the most appropriate streaming rate for a user based on their bandwidth. Users can no longer select the bitrate of their streaming as this is done automatically by the player.
Calculation is based upon the number of frames dropped per second - the player always tries to play the highest quality file at all times. Should the stream drop more than 25% of the frames needed to be streamed per second, the player determines that the available bandwidth for that user is not sufficient to support the current bit rate and automatically drops the user down to the next level of quality.
If no frames are dropped for a certain time, the player will try to move the user up to the next level of quality to check if they are able to sustain the higher rate. If they can't, the player will drop them down again.
Encoding and quality
Media playback requires your computer to 'stream' the media files. This is where a file is sent from our servers to your computer bit-by-bit. The file is temporary, meaning that you are not downloading a copy to keep. In order to achieve this, we encode 3 versions of each video at separate bit-rates. The 'bit-rate' is the amount of data we send to your computer each second. The higher the bitrate, the higher the quality, and the greater the bandwidth that is required.