[Speex-dev] Resample UltraWideBand to NarrowBand
Jean-Marc Valin
Jean-Marc.Valin at USherbrooke.ca
Wed Mar 18 08:20:43 PDT 2009
Quoting Jim Crichton <jim.crichton at comcast.net>:
> The resampler will convert raw audio from one sample rate to another. You
> are starting with Speex-encoded audio frames. So, what you need to do is:
>
> 1. Run the media frames through the Speex decoder (look at Speexdec or
> testenc_uwb). This will give you raw audio with a 32 KHz sample rate.
> 2. Use the resampler to convert the audio from 32 KHz to 8 KHz sample rate.
> 3. Run the 8KHz audio through a G711 encoder.
>
> For the narrowband case, Asterisk is doing steps 1 and 3.
Alternatively, it's possible to use a narrowband Speex decoder to decode a 32
kHz stream, in which case you'll get the 8 kHz directly.
Jean-Marc
> ----- Original Message -----
> From: Thiago Maluf
> To: speex-dev at xiph.org
> Sent: Tuesday, March 17, 2009 4:59 PM
> Subject: [Speex-dev] Resample UltraWideBand to NarrowBand
>
>
> Hi List,
> Now I will send to you more specific what I am trying to do.
> I have one Asterisk Channel where receives Midia Frames in the codecs
> format: Speex UltraWideBand and Speex NarrowBand.
> When I use Speex NarrowBand the Asterisk is able to convert this frame to
> G711.
> But when I use Speex UltraWideBand the Asterisk don't convert it.
> Then I need in my Asterisk Channel Source include the Speex Library in
> resample this frame in 32KHz to 8KHz.
> Searching for it in Speex Doc, I found it:
>
> SpeexResamplerState *resampler;
> resampler = speex_resampler_init(nb_channels, input_rate, output_rate,
> quality, &err);
> err = speex_resampler_process_int(resampler, channelID, in, &in_length,
> out, &out_length);
>
> But in my source I have one *dataframe where is my payload. How I can use
> it to resample my frame?
> Thanks you very much, Thiago.
>
>
>
> ------------------------------------------------------------------------------
>
>
> _______________________________________________
> Speex-dev mailing list
> Speex-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
>
More information about the Speex-dev
mailing list