Significant characteristics of video files

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• From Arts and Humanities Data Service Preservation Handbook: Moving Image, Gareth Night, 2005: "For preservation purposes, the significant properties of digital video are the video length (e.g. 90 minutes, 20 seconds), frames per second (25 for PAL, 30 for NTSC), video dimensions (e.g. 720 pixels x 576 pixels), bit-rate (kbps), associated metadata, and file size. If audio is also provided, the audio bit-rate (kbps), frequency (kHz), and number of channels." (p.7)

• From The Significant Properties of Moving Images, Mike Coyne and Mike Stapleton, 2008, adapted from table on pages 61-2. Note that this table excludes properties intrinsic to audio aspects of moving image files:

property value	component	property definition	constraint unit	datatype
imageStreams	video	the number of distinct video channels in the digital object	channels	positive integer
audioStreams	audio	the number of distinct audio channels in the digital object	channels	positive integer
length	video	the number of frames in the recording	frames	positive integer
width	frame	width of the image frame	pixels	positive integer
height	frame	height of the image frame	pixels	positive integer
bitDepth	pixel	the amount of data recorded for each pixel	bits	positive integer
colourModel	pixel	the colour model used when recording the pixel value	enumerated list
colourSpace	pixel	the colour space used when recording the pixel value	enumerated list
pixelAspectRatio	pixel	aspect ratio of the pixels making up the image	ratio	ratio
frameRate	video	the number of frames to be displayed in a given time interval	frames per second	positive integer?
lossless	video	whether the encoding is lossless	enumerated list
compressionRatio	video	measures the degree of compression employed by the encoding	ratio	ratio
codec	video	identifies the codec used for encoding	enumerated list	name
interlace	frame	whether the source was interlaced video	boolean	boolean
metadata		the existence of metadata associated with the digital object	elements