Hikvision built-in microphone codec selection?

[webdude]

Hi All,

I have Hikvision DS-2183G2-IU with a built-in microphone installed in a hall and I'm facing bad sound clarity on playback. My question is if I switch the codec to AAC instead of G711 does it change the audio clarity to better? Shall I keep H265 with AAC or switch to H264 with AAC?

N.B: the height between the ground and ceiling is 275 cm only.

Thanks for your support.

​

 

[David]

Hi All,

I have Hikvision DS-2183G2-IU with a built-in microphone installed in a hall and I'm facing bad sound clarity on playback. My question is if I switch the codec to AAC instead of G711 does it change the audio clarity to better? Shall I keep H265 with AAC or switch to H264 with AAC?

N.B: the height between the ground and ceiling is 275 cm only.

Thanks for your support.

​

The G711 codec is very robust, are you using u (mu) or A law? if mu try A or vice versa.

David

 

[webdude]

hello David

thanks for the reply.

so you do not recommend AAC at all? I'm using the default settings which I guess is "u".

Whats the difference between U and A law? and does it affect the clarity?

 

[rorton]

I did quite a bit of testing on this, and found G722.1 to be the best overall quality. The others caused some loss to the higher frequencies.

Try for yourself, but for me, it was the better codec

EDIT - just did some reading about AAC, in theory is should be a better codec as more bandwidth and frequencies. Im not 100% if I settled on G722 when I had an older recorder, but I do remember it covering more frequencies that 711

this was a snip from a site I read - I may go back and review my settings again now!

AAC	80 - 320 kbps	Excellent, full-range audio quality for medium bitrates. Slightly higher delay. Error concealment.	Music at medium bitrates. For the medium range of bitrates, this is the best codec to choose when a little delay is OK. Quality is fully “awesome”, especially at 256 kbps and higher.
Layer 2	112 - 384 kbps	Excellent quality at medium-high bitrates. Very compatible with other brands of equipment.	Music/voice at medium bitrates to other brands of codecs. Layer 2 is a great choice, especially for compatibility across different brands of codecs.
G.722	64 kbps	Good voice quality (7 kHz) when low delay and com- patibility is needed. Also called “HD Voice”	Voice at low bitrate to other brands of codecs. Not “high quality”, but much better than a standard telephone call. It’s the most compatible low bitrate codec with any other brand.
G.711	56 - 64 kbps	Low quality, low delay mono voice. Only 3.3 kHz audio.	This is a “phone call”. Often used for compatibility for SIP (VoIP) calls to/from regular telephones.

 

[David]

so you do not recommend AAC at all? I'm using the default settings which I guess is "u".

I would try AAC, it's been a few years since I last tried it. It gave me problems across mobile data networks so I settled on A-Law.

Whats the difference between U and A law? and does it affect the clarity?

Mainly frequency response, u-Law gives a better high frequency response. A-Law is more flat. As @rorton says frequency response is 300Hz to 3KHz, basic telephone call quality. Good for my deaf old ears.

G711 was primarily used for E1 30 channel PCM trunk audio and signalling (time slot 16) between telephone exchanges and ISDN data transfer, u-Law North America and A-Law Europe.

Have you checked the microphone holes for dirt etc?

David