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Discussion Groups | Speech Coding | AMR coding mode determinating
Technical discussions related to Speech Coding (all itu and other vocoders, ACELP, CELP, AMR, etc)
AMR coding mode determinating - 天才 - Sep 13 3:02:00 2002
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hi all, I am wondering to know the procedure and which module that determinat the AMR coding mode (different bit rate). Besides, please introduce some reference articles for me about this to read. Regards, lee |
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Re: AMR coding mode determinating - Julien VILLERET - Sep 13 13:37:00 2002
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Hi, All I know comes from a bit of reading on AMR signalling in a mobile phone. I hope this helps: in-band control bits are sent - DownLink ( Base Station to Mobile ) Mobile reveives the bitrate to use for decoding (-> CMI = Codec Mode Indication ) alongside the speech bitstream. The CMI is chosen by the Base Station depending on Uplink connection quality criteria. - UpLink ( Mobile to Base Station ) To encode user's speech, the mobile is also being given a bitrate mode along the downstream ( -> CMC = Codec Mode Command ). The mobile also polls downlink quality and sends the base station a request for increasing or decreasing the bitrate for downstream ( -> CMR = Codec Mode Request ). Then the BS decides whether to take it into account or not. If you want to read more go to http://www.etsi.org and have a search for spec GSM 05.09 : Link adaptation. have fun Julien Villeret 天才 wrote: > > hi all, > > I am wondering to know the procedure and which module that determinat > the AMR coding mode (different bit rate). Besides, please introduce > some reference articles for me about this to read. > > Regards, > lee > _____________________________________ > > | |||||||
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Re: AMR coding mode determinating - M Shehzad Hanif - Sep 13 17:50:00 2002
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Hi, My Question is regarding the AMR Mode adaptation on the IPNetwork. That is when AMR is wroking with RTP. Is there any kind of Recommendation on this( like GSM 05.90 for Cellular transmission). Any kind help is most welcomed. Regards Shehzad Hanif ----- Original Message ----- From: "Julien VILLERET" <> To: <> Sent: Friday, September 13, 2002 6:37 PM Subject: Re: [speechcoding] AMR coding mode determinating > Hi, > > All I know comes from a bit of reading on AMR signalling in a mobile > phone. I hope this helps: > > in-band control bits are sent > > - DownLink ( Base Station to Mobile ) > > Mobile reveives the bitrate to use for decoding (-> CMI = Codec Mode > Indication ) alongside the speech bitstream. The CMI is chosen by the > Base Station depending on Uplink connection quality criteria. > - UpLink ( Mobile to Base Station ) > > To encode user's speech, the mobile is also being given a bitrate mode > along the downstream ( -> CMC = Codec Mode Command ). > > The mobile also polls downlink quality and sends the base station a > request for increasing or decreasing the bitrate for downstream ( -> CMR > = Codec Mode Request ). Then the BS decides whether to take it into > account or not. > > If you want to read more go to http://www.etsi.org and have a search for > spec GSM 05.09 : Link adaptation. > > have fun > > Julien Villeret > > 天才 wrote: > > > > hi all, > > > > I am wondering to know the procedure and which module that determinat > > the AMR coding mode (different bit rate). Besides, please introduce > > some reference articles for me about this to read. > > > > Regards, > > lee > > > > > > _____________________________________ > > > > > > > > > > _____________________________________ |
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