video_files:formulas
Table of Contents
Video Files - Formulas
General
File size = bitrate * number of minutes * .0075 Bitrate = file size / (number of minutes * .0075) Number of minutes = file size / (bitrate * .0075) otherwise GB = mbps * minutes * .0075 mbps = GB / (minutes * .0075) minutes = GB / (mbps * .0075)
NOTE: The .0075 is derived from the following:
- As there are 8 bits per byte, it is required to device by 8 to determine the bits.
- To convert the number of minutes to seconds, multiply by 60.
- Divide by 1,000 to to convert megabits (Mb) to megabytes (MB), or megabytes to gigabytes.
1/8 * 60 / 1000 = 0.0075.
Picture File Size
File Size = width x height x colour depth x frame rate x duration
NOTE:
- width: In pixels.
- height: In pixels.
- color depth: The number of bits used to encode the colour of one pixel.
- A 1-bit colour depth means that the graphic can only include 2 colours (e.g. 1 = black, 0 = white).
- A 8-bit colour depth means that the graphic can include up to 256 colours.
- A 3-Byte colour depth (RGB code) would include 16,777,216 colours.
- RGB would have a color depth of 3 (24 bits; 8 bits for Red, 8 bits for Green, 8 bits for Blue).
- A 4-Byte color depth (RGBA) can also be used. (32 bits; 8 bits for Red, 8 bits for Green, 8 bits for Blue; 8 bits for Alpha).
- frame rate: in fps (frame per seconds).
- duration: in seconds.
Sound File Size
Sound File Size = sample rate x duration x bit depth x number of channels
NOTE:
- sample rate: The number of samples being recorded per second; (such as 48,000 samples per second).
- duration: In seconds.
- bit depth: The number of bits used to record one sample.
- channels: 1 is mono, 2 is stereo, 6 is dolby-surround.
Bitrate
Bitrate = file size / (number of minutes * .0075) Bitrate = (file size * 8) / (duration in seconds) Video Bitrate = Total Bitrate - Audio Bitrate
Duration
Number of minutes = file size / (bitrate * .0075).
Filesize
file size = bitrate * number of minutes * .0075 file size = duration × frame rate × frame size frame size = H × V × color depth color depth = 8bitxRGB = 8*3 = 24 Picture File Size = colour depth x width in pixels x height in pixels colour depth = RGB=3 bytes; RGBA=4 bytes file size = bitrate * time file size = duration × file size per sec / 8 file size per second = fps × frame size Video File Size = (Bitrate / 8) × Duration File Size (in Bytes)=(Video Bitrate × Duration)+Audio Bitrate File Size (in Bytes)=(Video Bitrate × Duration)+((Audio Bitrate x Audio Size)/Audio Channels*6) Compressed Video File Size (GB) = (Bitrate (Mbps) * Total Time (seconds)) / (8 * 1024)
Sound Bitdepth
See bits per raw sample field.
An approximation of the sound bitdepth can be calculated by using variables: audio sample rate, audio channels and audio bitrate.
audio bitdepth = audio bitrate / audio_channels / audio sample rate
NOTE: The audio bitrate may need to be multiplied by 1,000 to be in bits.
- This formula should produce a value such as 1, 2, 3 or 4; which is the number of bytes.
- When these bytes are multiplied by 8 to convert them to bits, this will result in 8, 16, 24, or 32 bits.
Sound Bitrate
bit rate = audio sample rate * audio channels * audio bit depth
Sound File Size
Sound File Size = sample rate x duration x bit depth x number of channels
video_files/formulas.txt · Last modified: 2025/05/17 07:24 by peter