Re: [codec] #7: Providing DTMF Testing Tools and Samples

"codec issue tracker" <> Sat, 10 April 2010 05:39 UTC

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Subject: Re: [codec] #7: Providing DTMF Testing Tools and Samples
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#7: Providing DTMF Testing Tools and Samples
 Reporter:  hoene@…                 |       Owner:     
     Type:  task                    |      Status:  new
 Priority:  minor                   |   Milestone:     
Component:  requirements            |     Version:     
 Severity:  Active WG Document      |    Keywords:     

Comment(by hoene@…):

 Koen Vos:

 It's unclear what to test about DTMF though. The Codec will support a
 range of sample rates and bitrates. The requirements specify coding of
 music at near-transparent quality. I don't see how a such a codec could
 not provide sufficient quality for in-band DTMF. At the same time, the
 requirements talk about bitrates down to 8 kbps, where it may be quite
 tricky to get DTMF to work well. Therefore, specifying that the codec
 SHOULD or MUST encode DTMF with sufficient quality is meaningless. If
 anything, the bitrate settings that allow in-band DTMF could be
 characterized after the Codec is formed.

 Nevertheless it's good to be aware of these use cases during development.
 For instance, with SILK we included DTMF signals in the LSF quantizer
 training database.

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