Principles & Method Description

Frame Rate, Bitrate & Resolution

Frame rate refers to the number of images captured per second. Resolution stands for the pixel dimensions of each frame. Bitrate means the data volume generated every second after video compression. Video compression eliminates spatial redundancy within frames and temporal redundancy between consecutive frames.For static scenes, a low bitrate can deliver decent image quality. For scenes with drastic motion, even a high bitrate may fail to produce clear footage. Conclusion: Frame rate defines real-time performance; resolution sets the display size of footage; bitrate shall be configured based on camera models and actual scenarios. On-site debugging is required to confirm a suitable bitrate that meets acceptable image quality standards.

Definition of Frame Rate

A frame is a static picture; sequential frames form moving visuals such as TV footage. Frame rate (FPS, Frames Per Second) describes how many frames are transmitted within one second, or the refresh frequency of a graphics processor per second. Each frame is a still image; rapid sequential playback creates the illusion of motion. Higher frame rates deliver smoother, more lifelike motion. The higher the FPS value, the fluider the displayed movements.

Definition of Bitrate

Bitrate (Data Rate) denotes the data traffic consumed by video files per unit time, also called data transfer rate. It is the core parameter controlling image quality during video encoding. Under identical resolution, higher bitrate means lower compression ratio and superior image clarity.

Definition of Resolution

Video resolution represents the pixel dimensions of images captured by video imaging devices. Common surveillance resolutions include 352×288, 176×144, 640×480, 1024×768. In resolution notation, the first number stands for image width and the second for height; their product equals total pixels. Most traditional resolutions adopt a 4:3 aspect ratio.

Hard Disk Capacity Calculation

Basic Data Units

bit (binary digit): The smallest unit for measuring digital data. Each binary digit 0 or 1 equals one bit. Application: Measure data transmission speed, unit: bit/s, b/s, Kb/s, Mb/s, Gb/s, Tb/s, bps (bit per second). Prefix definitions: K=kilo, M=mega, G=giga, T=tera.

Unit Conversion Table

1 Byte = 8 bit 1 KB = 1024 Bytes = 8 × 1024 bits 1 MB = 1024 KB 1 GB = 1024 MB 1 TB = 1024 GBByte: The standard unit for data transmission over networks and storage on hard drives/memory. All network data is transmitted in bits; 8 bits form one Byte.

• 1 English character (uppercase/lowercase) occupies 1 Byte in ASCII code
• 1 Chinese character occupies 2 Bytes
• English punctuation marks take 1 Byte; Chinese punctuation marks take 2 Bytes

A Byte is an 8-bit binary value ranging from 0 to 255. Full storage unit hierarchy (binary 1024-based conversion): 1 KiB (Kibibyte) = 1024 Bytes 1 MiB (Mebibyte) = 1024 KiB 1 GiB (Gibibyte) = 1024 MiB 1 TiB (Tebibyte) = 1024 GiB 1 PiB (Pebibyte) = 1024 TiB 1 EiB (Exbibyte) = 1024 PiB 1 ZiB (Zebibyte) = 1024 EiB 1 YiB (Yobibyte) = 1024 ZiB 1 BB (Brontobyte) = 1024 YiB

Key Distinction: MiB vs MB, KiB vs KB

• 1 KB (Kilobyte, decimal) = 1000 Bytes
• 1 KiB (Kibibyte, binary) = 1024 Bytes
• 1 MB (Megabyte, decimal) = 1,000,000 Bytes
• 1 MiB (Mebibyte, binary) = 1,048,576 Bytes

Hard disk manufacturers calculate capacity using decimal base-1000 units (1MB=1000KB), while operating systems use binary base-1020 units (1MiB=1024KiB). Most domestic users conventionally equate 1MB to 1024KB, so MiB is commonly simplified to MB for local comprehension.Due to this calculation difference, a 160GB labeled hard drive shows less usable space in Windows systems, which explains the "missing capacity" phenomenon on new storage disks. Capacity deviation ratio: ~5% for MB notation, ~7.4% for GB notation, up to 10% for TB notation. Note: Approximately 10TB equals the estimated storage capacity of a human brain.

kbps (Bitrate) Explanation

Data transfer rate over digital channels is also named bitrate. It refers to the number of bits consumed per second by compressed audio/video streams. Higher bitrate delivers better image quality yet larger file size, and vice versa. Example: 500 kbps encoding Conversion rule: 1 KB/s = 1024 × 8 bps

• b = bit
• s = second
• p = per 500 kbps means the encoded video stream consumes 500 kilobits of data every second.

Standard Bitrates for Common Video Resolutions

• D1: 512 kbps
• 720P: 2048 kbps
• 1080P: 4096 kbps

Hard Disk Capacity Calculation Formula

Variables:

• S = Storage capacity (Unit: MB, Megabyte)
• D = Bitrate (Unit: kbps, Kilobit per second; 8 bit = 1 Byte)
• 1 hour = 3600 seconds

Formula for 1-channel video storage consumption per hour: S₁ (MB) = D (kbps) ÷ 8 × 3600 ÷ 1024 (1 MB = 1024 KB)This formula calculates the hard disk capacity required for video surveillance recording. Online calculation tool: http://t.cn/zOyfLf9 Supports quick calculation of the unknown value given any two parameters among recording file size, recording duration and video bitrate.