Hi All!
Can anybody tell me what is the reason for using the internal sampling frequency
in the AMR WB codec as 12.8kHz and not the actual input sampling frequency of
the input signal, 16kHz?
Thanks in advance.
Nishit Jain
Great minds have purposes, little minds have wishes.
AMR WB internal Sampling Frequency 12.8 kHz?
Started by ●October 10, 2006
Reply by ●October 10, 20062006-10-10
Hi,
AMR-WB treats band width 50 Hz-6.4 kHz and 6.4 kHz-7 kHz
differently and hence uses internal sampling frequency of 12.8 kHz.
Regards,
Ashish Malot
-----Original Message-----
From: a... [mailto:a...] On
Behalf Of Nishit Jain
Sent: Monday, October 09, 2006 5:26 PM
To: a...
Subject: [audiodsp] AMR WB internal Sampling Frequency 12.8 kHz?
Hi All!
Can anybody tell me what is the reason for using the internal sampling
frequency in the AMR WB codec as 12.8kHz and not the actual input
sampling frequency of the input signal, 16kHz?
Thanks in advance.
Nishit Jain
Great minds have purposes, little minds have
wishes.
AMR-WB treats band width 50 Hz-6.4 kHz and 6.4 kHz-7 kHz
differently and hence uses internal sampling frequency of 12.8 kHz.
Regards,
Ashish Malot
-----Original Message-----
From: a... [mailto:a...] On
Behalf Of Nishit Jain
Sent: Monday, October 09, 2006 5:26 PM
To: a...
Subject: [audiodsp] AMR WB internal Sampling Frequency 12.8 kHz?
Hi All!
Can anybody tell me what is the reason for using the internal sampling
frequency in the AMR WB codec as 12.8kHz and not the actual input
sampling frequency of the input signal, 16kHz?
Thanks in advance.
Nishit Jain
Great minds have purposes, little minds have
wishes.
Reply by ●October 12, 20062006-10-12
Hi there,
I would add to this that the lower band ( < 6400Hz) is coded using the
CELP (or ACELP more precisely) which is hybrid coder (a
waveform/parametric coder), while the upper band (6400< f < 7000Hz) is
generated at the decoder side using bandwidth extention. Since the
upper band is mostly a modulated noise, it is more efficient to
concentrate the available bits to encode the lower band.
Why exactly 12800Hz, because it makes the implementation of the
interopolation filter simpler: 12800/16000 = 4/5.
regards
--- In a..., "Ashish Malot" wrote:
>
> Hi,
> AMR-WB treats band width 50 Hz-6.4 kHz and 6.4 kHz-7 kHz
> differently and hence uses internal sampling frequency of 12.8 kHz.
> Regards,
> Ashish Malot
>
> -----Original Message-----
> From: a... [mailto:a...] On
> Behalf Of Nishit Jain
> Sent: Monday, October 09, 2006 5:26 PM
> To: a...
> Subject: [audiodsp] AMR WB internal Sampling Frequency 12.8 kHz?
>
> Hi All!
>
> Can anybody tell me what is the reason for using the internal sampling
> frequency in the AMR WB codec as 12.8kHz and not the actual input
> sampling frequency of the input signal, 16kHz?
>
> Thanks in advance.
>
> Nishit Jain
> Great minds have purposes, little minds have
> wishes.
>
I would add to this that the lower band ( < 6400Hz) is coded using the
CELP (or ACELP more precisely) which is hybrid coder (a
waveform/parametric coder), while the upper band (6400< f < 7000Hz) is
generated at the decoder side using bandwidth extention. Since the
upper band is mostly a modulated noise, it is more efficient to
concentrate the available bits to encode the lower band.
Why exactly 12800Hz, because it makes the implementation of the
interopolation filter simpler: 12800/16000 = 4/5.
regards
--- In a..., "Ashish Malot" wrote:
>
> Hi,
> AMR-WB treats band width 50 Hz-6.4 kHz and 6.4 kHz-7 kHz
> differently and hence uses internal sampling frequency of 12.8 kHz.
> Regards,
> Ashish Malot
>
> -----Original Message-----
> From: a... [mailto:a...] On
> Behalf Of Nishit Jain
> Sent: Monday, October 09, 2006 5:26 PM
> To: a...
> Subject: [audiodsp] AMR WB internal Sampling Frequency 12.8 kHz?
>
> Hi All!
>
> Can anybody tell me what is the reason for using the internal sampling
> frequency in the AMR WB codec as 12.8kHz and not the actual input
> sampling frequency of the input signal, 16kHz?
>
> Thanks in advance.
>
> Nishit Jain
> Great minds have purposes, little minds have
> wishes.
>
