[Speex-dev] Delays estimation in Speex algorithms

[Alexander Chemeris]

First patch fixes two typos in manual.

Second patch adds few notes about latency, as promised.
Hopefully I haven't added any typos and grammar errors :)

On Wed, Jul 1, 2009 at 8:02 PM, Alexander
Chemeris<Alexander.Chemeris at sipez.com> wrote:
> Thank you for clarification. I attached a patch which (IMHO)
> makes it more clear for everyone who just read Doxygen
> docs. Resampler latency docs wording was just ambiguous
> IMO, so I made it more robust to fast reading.
>
> On Wed, Jul 1, 2009 at 5:16 PM, Jean-Marc
> Valin<jean-marc.valin at usherbrooke.ca> wrote:
>> Alexander Chemeris a écrit :
>>> On Tue, Jun 30, 2009 at 4:38 AM, Jean-Marc
>>> Valin<jean-marc.valin at usherbrooke.ca> wrote:
>>>> Alexander Chemeris a écrit :
>>>>> 2) decoder (I guess it should be 0?)
>>>> 5 ms
>>>
>>> Hum, interesting. So, e.g. for NB mode delay is
>>> 20 (packet size) + 5 (encoder lookahead) + 5 (decoder delay) = 30, right?
>>
>> Correct
>>
>>>>> 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
>>>
>>> Seems we need to update our Speex sources. Our version has no
>>> speex_resampler_get_[out|in]put_latency() functions. Should I
>>> sum values of input and output latency to get overall latency?
>>> Actually, why do you separate input and output latency? For
>>> a user, resampler is a black-box, which logically has a single
>>> latency value. Two latencies are confusing.
>>
>> You don't sum them, you just get the latency in different units.
>> speex_resampler_get_input_latency() will return the latency in input
>> samples, while the other will give you the same value, but expressed as
>> a number of output samples.
>>
>>        Jean-Marc
>>
>
>
>
> --
> Regards,
> Alexander Chemeris.
>
> SIPez LLC.
> SIP VoIP, IM and Presence Consulting
> http://www.SIPez.com
> tel: +1 (617) 273-4000
>



-- 
Regards,
Alexander Chemeris.

SIPez LLC.
SIP VoIP, IM and Presence Consulting
http://www.SIPez.com
tel: +1 (617) 273-4000
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