# Re: [music-dsp] Reading a buffer at variable speed

```>>>> The buffer must be read at a variable speed,

>>Do you mean it has to be played out at higher sample rates ?
yes it has to be played out at higher sample rates, so I start at the
original sample rate and end at sample rate * some chosen value```
```
>>>> how long will it take to play the whole buffer

>>If you can derive an average rate out of it then you can determine it.

could you explain me how?

2018-02-06 17:15 GMT+01:00 Benny Alexandar <ben.a...@outlook.com>:

> >> The buffer must be read at a variable speed,
>
> Do you mean it has to be played out at higher sample rates ?
>
> >> how long will it take to play the whole buffer
>
> If you can derive an average rate out of it then you can determine it.
>
> -ben
>
> ------------------------------
> *From:* music-dsp-boun...@music.columbia.edu <music-dsp-bounces@music.
> columbia.edu> on behalf of Maximiliano Estudies <maxiestud...@gmail.com>
> *Sent:* Tuesday, February 6, 2018 8:15 PM
> *To:* music-dsp@music.columbia.edu
> *Subject:* [music-dsp] Reading a buffer at variable speed
>
> I am having trouble with this concept for quite some time now, I hope that
> I can explain it well enough so you can understand what I mean.
> I have signal stored in a buffer of known length. The buffer must be read
> at a variable speed, and the variations in speed have to be exponential, so
> that the resulting glissandi are (aurally) linear. In order to do that I
> came up with the following formula:
>
> x[t] = t * sample_rate * end_speed^(x[t] / T)     where T is the total
> length of the buffer in samples.
>
> This doesn’t seem to work and I can’t understand why.
>
> And my second question is, how can I get the resulting length in
> milliseconds? (how long will it take to play the whole buffer)
>
> I hope I managed to be clear enough!
>
> Maxi
>
> --
> Maximiliano Estudies
> +49 176 36784771 <+49%20176%2036784771>
> maxiestudies.com
>

--
Maximiliano Estudies
+49 176 36784771
maxiestudies.com
```
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