Interpolated ADPCM

Started by zhoujinxi June 12, 2007
Hi all,

I am developping an real time audio compression codec system.In my system
I adopted 16-bit 48kHz to 5 bit 48kHz IMA-ADPCM algorithm,but could not
get the satisfied results,audio result was not good.

I know from someone,there is an tech call "interpolated" will do the job.

I would like to hear from some one how to work with interpolated or get
some useful web URL for it.

Thanks in advance.

zhoujinxi




zhoujinxi wrote:

> I am developping an real time audio compression codec system.In my system > I adopted 16-bit 48kHz to 5 bit 48kHz IMA-ADPCM algorithm,but could not > get the satisfied results,audio result was not good. > > I know from someone,there is an tech call "interpolated" will do the job.
1. ADPCM sucks and there is no silver bullet. 2. IMA ADPCM sucks even more, because it lacks adaptive backward predictor. Use MS ADPCM. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
> > >zhoujinxi wrote: > >> I am developping an real time audio compression codec system.In my
system
>> I adopted 16-bit 48kHz to 5 bit 48kHz IMA-ADPCM algorithm,but could
not
>> get the satisfied results,audio result was not good. >> >> I know from someone,there is an tech call "interpolated" will do the
job.
> >1. ADPCM sucks and there is no silver bullet. >2. IMA ADPCM sucks even more, because it lacks adaptive backward >predictor. Use MS ADPCM. > > >Vladimir Vassilevsky > >DSP and Mixed Signal Design Consultant > >http://www.abvolt.com >
First of all,thanks for reply! I konw some variation of IMA_ADPCM,MS-ADPCM,SUB-ADPCM could get better result than ADPCM,but in our system,the fixed-point processor work in 49.152MHz without hardware multiplier,so some complicated algorithm will not suit for our system. The IMA-ADPCM that we adopted have adaptive backward predictor and adaptive step adjustment of quantizer,so we achieves a THD+N of 0.48% @ 1kHz,but our custmer require better result. I know from someone,there is an technique call "interpolated" will do the job.I disire for someone could help me for it! Thanks in advance! Zhoujinxi