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)?
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;
> ......
> }
> ------------------------------------------------------------------------
>
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