AV Terms and Acronyms Follow

This article covers common terms and descriptions when discussing streaming and AV production.  

• Adaptive Bit Rate (ABR) - Adaptive bitrate streaming or ABR streaming, sometimes shortened to ABS, is a technique for dynamically adjusting the compression level and video quality of a stream to match bandwidth availability.
• Content Delivery Network (CDN) - A geographically distributed network of proxy servers and their data centers. The goal is to provide high availability and performance by distributing the service spatially relative to end users.
• Destination - The place that will receive your live stream output, i.e.: YouTube, Vimeo, Wowza.  
• Encoder - This is the hardware or software device that converts a live broadcast into a data stream to send to a Destination.
• HTTP Live Streaming (HLS) - This is a streaming method that was developed by Apple and is now widely used to display streaming media content on the web.
• Interlaced Footage (1080i) - Interlaced footage describes how the video signal is processed.  Interlaced means that that every other line of footage is rendered on a display.  This was used in the UHF and cable broadcast television to decrease bandwidth.  Tube televisions would only display every other line of video for each frame, but as it was happening faster than the eye could detect, it looked as if all the pixels were lit at the same time.
• Last Mile/First Mile - These terms are used to describe the internet connections from the user streaming to the Destination (first mile) and the user playing the video from the Destination (last mile).  These are usually uncontrolled areas where various problems might occur with media playback.  
• Latency  - How long it takes for your live stream to leave the Encoder and reach your attendee's screen.  
• m3u / m3u8 - File format for a multimedia playlist that is also accepted in the "external link" field on Pathable.
• Progressive Footage (1080p) - Progressive footage describes how the video signal is processed.  Progressive means that every line of pixels is rendered for each frame of video usually 30 times per second.  The alternative to Progressive is Interlaced footage which is not compatible with computers, modern displays and devices.
• Real Time Messaging Protocol RTMP(S) - A common encoding solution to send video from your encoder to a destination or transcoder.  (S) indicates a Secure connection that uses additional encryption to ensure no unauthorized viewership.
• Transcoding - Transcoding is the process of converting an audio or video file from one encoding format to another in order to increase the number of compatible target devices a media file can be played on.
• 1080p, 720p, 360p - These are common terms to describe the video resolution.  The number corresponds to the vertical pixel height of the video, i.e.: 1920 X 1080, whereas the "P" signifies a progressive video format.