Chuck-
> I believe Ranjeet's numbers are not referring to
G729 other than
> specifying
> 10 ms as the "comparison period". His numbers are perfectly correct for
> the
> raw audio. His mistake is the same as the first poster: the comparison
> point
> for compression is not normally the raw audio but rather G.711.
Yes. I think we're all on the same page now.
-Jeff
> _____
>
> From: s... [mailto:s...]
> On
> Behalf Of Jeff Brower
> Sent: Saturday, August 19, 2006 10:05 AM
> To: Ranjeet Gupta
> Cc: Bineesh Jose; s...
> Subject: Re: [speechcoding] Compression In G.729
>
> Ranjeet-
>
>> Comment Embedded !
>>
>> On Thu, 17 Aug 2006 bineeshjose@
> gmail.com wrote :
>>>Hi all,
>>> Now I am working with ITU-T's G.729 recommentation. I have one
>>> doubt.As you know In G.729 Codec the compression rate is 1/8. But
>>> here in 10 ms, 80 words(160 bytes) are compressed into 80 bits(10
>>> bytes).Then how can we say this is 1/8th compression?
>>
>> 10 milisecond data = one frame;
>> One Frame = 80 samples of speech wave,
>> 1 sample = 16bit data
>> 16bit = 2 bytes
>>
>> so conclusion is 1 frames = 80 samples of speech = 160 bytes.
>> So 160 bytes makes One frame, which is to be processed by ITU G729
>> Algorthim.
>>
>> When you get the encoded data then the resultant size is 20bytes. or
>> 10Samples (one Sameple = 16bit data)
>
> No. G.729AB codec output framesize is 80 bits, or 10 bytes, as Bineesh
> mentioned. Some applications transmit *two* frames per packet as the
> voice payload, but that has to do with bandwidth efficiency, not the
> compression rate of the codec. Here is a nice page with concise
> information:
>
> http://www.newport-
>
> networks.com/whitepapers/voip-bandwidth3.html
>
> -Jeff
Compression In G.729
Started by ●August 17, 2006
Reply by ●August 22, 20062006-08-22
