[Speex-dev] Delays estimation in Speex algorithms

[Jean-Marc Valin]

Thanks for the patch. It's applied now.

Alexander Chemeris a écrit :
> 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
>>
> 
> 
>