Video Spec Definitions Video File size – The measure of space a file takes on a storage medium such as a computer hard drive. File sizes can be measured in bytes (B), kilobytes (KB), megabytes (MB), gigabytes (GB), and beyond File format – One of many standard ways for information to be encoded for storage. Examples for video include .flv, .mp4, .wmv, etc. Dimensions – The width and height of a particular video, measured in pixels. Common high-definition dimensions include 1280×720 and 1920×1080 Aspect ratio – The ratio of the video’s width to the video’s height. For example, a video with dimensions of 1280×720 has an aspect ratio of 16:9 Bitrate mode – The method by which the video file is encoded, either constant bitrate (CBR) or variable bitrate (VBR). Constant bitrate encoding persists the set data rate over the entire video file. Variable bitrate encoding adjusts the data rate based on the data required by the compressor and can result in portions of the video being under the minimum required bitrate. Bitrate – The number of bits used per second of playback time. High definition video requires a minimum of 15 MBPS (15 Megabytes per second). Frame rate mode – The method by which the video file is rendered, either constant frame rate (CFR) or variable frame rate (VFR). Constant frame rate encoding persists the set frame rate over the entire video file. Variable frame rate encoding adjusts the frame rate based on the perceived level of motion in the video and can result in portion of the video being under the minimum required frame rate. Frame rate – The number of frames or images that are projected or displayed per second. Common frame rates used in the US are 23.98 and 29.97 fps. Black bars – Whether or not the video file contains black bars on the sides of the frame (pillarboxing) or on the top and bottom of the frame (letterboxing). Audio Codec – A device or program used for encoding or decoding a digital data stream. Codec is a portmanteau of coder-decoder. Bitrate – The number of bits used per second of playback time. High definition audio requires a minimum of 192 kbps (192 Kilobits per second). Bit depth – The number of bits of information in each sample. High definition audio requires a bit depth of either 16 or 24 bits. Sample rate – The number of samples of a sound that are taken per second to represent the event digitally. High definition audio requires a sample rate of exactly 48 kHz. Channels – A single stream of recorded sound with a location in a sound field (“left speaker” vs. “right speaker”). Digital audio should only ever have 2 channels. dBFS – Decibels relative to full scale (dBFS) is a unit of measurement for volume levels in digital systems which have a defined maximum peak level. This term is used to define the optimal audio volume level relative to the systems that will be processing the audio. Recommended dBFS is between -29dB and -25dB. Max Peak dB – The loudest single point of an audio file. Recommended Max Peak dB is -6dB and below.