It is MELP. I get the C source code at http://www.data-compression.com/melp1.2.tar.gz At the moment, I have no idea if I need to create a custom transport. I would like do some experiment about my question about the non-integer value in the default_attr function. At the same time, hope to get some help about this. ?2008-08-29 21:53:39?"Fabio Pietrosanti (naif)" <lists at infosecurity.ch> ??? >Sound like a very nice project, it's MELP or MELPe codec? > >For the RTP Profile are you going to create a custom transport? > >It's definitely an interesting project, is this for a mobile platform in >government area (MELP codecs are commonly used for law enforcement, >military and government operations)? > >Our company, KHAMSA SA, produce secure telephony applications and we are >looking for business and technology partner in the security area. Looks >like MELP codec are used only in military environment, maybe SCIP? > >Fabio > >wsycqyz wrote: >> Hi, >> I want to implement the MELP 2.4Kbps codec in the pjmedia_codec. >> As far as I know, MELP 2.4Kbps is running at 8KHz of sampling. Every >> frame has 180 samples(that is 22.5ms). Every frame is encoded to 54 >> bits. I will encode every frame to 56 bits(7 bytes) with padding 2 >> bits zero. >> I would like to use the gsm.c as a template. Now comes the question: >> >> Because the actual bit rate is: 56*1000/22.5=2488.89 and one frame is >> 22.5ms length, how can I set the attr->info.avg_bps, >> attr->info.max_bps and attr->info.frm_ptime in the default_attr function? >> >> ps: In gsm.c, code is like this: >> >> static pj_status_t gsm_default_attr (pjmedia_codec_factory *factory, >> const pjmedia_codec_info *id, >> pjmedia_codec_param *attr ) >> { >> PJ_UNUSED_ARG(factory); >> PJ_UNUSED_ARG(id); >> >> pj_bzero(attr, sizeof(pjmedia_codec_param)); >> attr->info.clock_rate = 8000; >> attr->info.channel_cnt = 1; >> attr->info.avg_bps = 13200; >> attr->info.max_bps = 13200; >> attr->info.pcm_bits_per_sample = 16; >> attr->info.frm_ptime = 20; >> attr->info.pt = PJMEDIA_RTP_PT_GSM; >> ...... >> } >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Visit our blog: http://blog.pjsip.org >> >> pjsip mailing list >> pjsip at lists.pjsip.org >> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20080830/a73158f0/attachment.html
