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Encoders - quantization

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Hi All,

 

I am reletively new to CCTV and have just started working with DVTel and other IP based CCTV products. I'm trying to get an understanding of the relationship between Quantizer and quality settings in encoders.

 

What are minimum and maximum quantizers?

How does setting he encoders to frame rate or bit rate effect quality, and how does the quantizer play its part in all this?

 

Many thanks,

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What are minimum and maximum quantizers?

How does setting he encoders to frame rate or bit rate effect quality, and how does the quantizer play its part in all this?

 

Many thanks,

 

The smaller the quantizer the higher quality the result but the more horsepower needed to encode.

 

Frame rate is pretty obvious, your eye percieves about 30 frames per second. It doesn't directly effect quality however it can on objects in motion.

 

Bit rate directly effects quality, the higher the bit rate the more image data is transmitted.

 

You may also have an option to set keyframe interval, a shorter interval will help with transmission across questionable networks as you will have fewer retransmits.

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Thanks for that.

 

So on the encoders i'm using I have options for Bit rate control and frame rate control.

 

If I set an encoder to frame rate control and it's minimum quantiser value (highest quality) does the bit rate value make any difference?

 

Does the encoder just use what it needs or does it try to keep the bit rate near to the set value?

 

What happens if at the above settings the maximum bit rate bandwidth on the encoder is reached by a very busy image? i.e. will it start to drop frames?

 

thanks again

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