[Speex-dev] Delays estimation in Speex algorithms

[John Ridges]

Speex tells me that the decoder is always 5 ms, but it says that the 
encoder is 5 ms for NB, 8.9375 ms for WB, and 10.90625 ms for UWB. Is 
there an extra frame of delay in the encoder that isn't otherwise 
accounted for?

John Ridges

Jean-Marc Valin wrote:
> Quoting John Ridges <jridges at masque.com>:
>   
>> I also need to know the precise delays from Speex but I used the
>> SPEEX_GET_LOOKAHEAD control requests to determine them (plus the
>> "speex_resampler_get_output_latency" function from the resampler). The
>> returned values from the Speex lookahead request don't seem to match
>> with the values you gave Alexander. Am I doing this wrong? Thanks,
>>     
>
> What's the difference between what I wrote and what you get from Speex?
>
>    Jean-Marc
>
>   
>> John Ridges
>>
>>
>> speex-dev-request at xiph.org wrote:
>>     
>>> Alexander Chemeris a ?crit :
>>>
>>>       
>>>> I want to do a careful measure of mic-to-net and net-to-spkr delays
>>>> in sip media engine and to make it really precise I need to know
>>>> delays, introduced by Speex algorithms. In particular, I'm interested
>>>> in delays of:
>>>> 1) encoder in NB, WB and UWB modes,
>>>>
>>>>         
>>> NB: 25 ms, WB: ~28 ms, UWB: ~30 ms
>>>
>>>
>>>       
>>>> 2) decoder (I guess it should be 0?)
>>>>
>>>>         
>>> 5 ms
>>>
>>>
>>>       
>>>> 3) resampler. I think it varies depending on input rate to output rate
>>>> ratio. Any generic formula or at least values for specific ratios
>>>>         
>> available?
>>     
>>> The higher the quality, the higher the delay
>>>
>>>
>>>       
>>>> 4) AEC
>>>>
>>>>         
>>> 0 ms
>>>
>>>
>>>       
>>>> 5) preprocessor
>>>>
>>>>         
>>> 1 frame extra delay (i.e. you get back the last frame you sent the last
>>> time)
>>>
>>> 	Jean-Marc
>>>
>>>
>>> ------------------------------
>>>
>>>
>>>
>>>       
>>
>>     
>
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