Bandwidth vs Quality

27 Jul 2011 Leave a Comment

by - Chinita in Recording Tags: CCTV, closed-circuit tv, gadgets, IP Cameras, Legal, Quezon City, surveillance, TCF, The Code Factory I.T. Solutions

Factors Impacting Quality

Even with the same resolution, two common settings impact quality:

• Bit Rate: Most cameras can have their bit rate adjusted to specific levels (e.g., 512 Kb/s, 2 Mb/s, 8Mb/s, etc.)
• Quantization Level: Most cameras can have the level of compression adjusted (often called a quality or compression setting with options from 1-10 or 0-100)

Typically, these are mutually exclusive. If you lock in bit rate, the camera will automatically adjust the quantization level to not exceed the bandwidth set. Vice versa, if you set the quantization level, the camera will automatically change the bandwidth consumed to make sure the quality / compression always stays at the same level.

Our Test Process

For the bandwidth tests, we tested each camera at the following levels:

• 512 Kb/s
• 1 Mb/s
• 2 Mb/s
• 4 Mb/s
• 8 Mb/s

We did this across a series of scenes to see how quality would vary in different conditions:

• Daytime Indoors (300 lux)
• Nighttime Indoors (.5 lux)
• Daytime Intersection

Source

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