Detecting first non silent sample index [COMPLETED]

Reply to Detecting first non silent sample index [COMPLETED] on Sat, 23 Jul 2016 15:29:36 GMT

pascal2000 — Sat, 23 Jul 2016 15:29:36 GMT

Hi,

I have an audio file that I read with [tabread~]). The audio starts with some silence and I am trying to find the first non silent sample index.

I have tried to use [bonk~], [fiddle~] or [sigmund~] but the results were approximate and not constants.

Does anyone have a solution for this? Thanks.

Pascal

Reply to Detecting first non silent sample index [COMPLETED] on Fri, 22 Jul 2016 14:02:32 GMT

gsagostinho — Fri, 22 Jul 2016 14:02:32 GMT

Is the sound completely silent up to that point (that is, is the table filled with zeroes up to that point)? Because if it is, I believe you can simply go through the array's elements, starting at the first one, checking if the absolute value of any of them is larger than zero. If the signal is not completely silent but near silent, then you will need some sort of attack detection such as [bonk~]. Why isn't it working for you, by the way?

Reply to Detecting first non silent sample index [COMPLETED] on Fri, 22 Jul 2016 14:10:18 GMT

pascal2000 — Fri, 22 Jul 2016 14:10:18 GMT

Thanks for the suggestion. Reading the table of course! I'll try that right now.
I had a solution with Bonk~but I found that the result was not precise enough.

Reply to Detecting first non silent sample index [COMPLETED] on Fri, 22 Jul 2016 17:21:32 GMT

pascal2000 — Fri, 22 Jul 2016 17:21:32 GMT

So I am reading my array until there is a non-zero value. It is working although silence is not necessarily a pure 0 value. I had to set a a low value threshold (positive and negative) . So far it is working ;^)

Reply to Detecting first non silent sample index [COMPLETED] on Fri, 22 Jul 2016 18:10:45 GMT

gsagostinho — Fri, 22 Jul 2016 18:10:45 GMT

It is working although silence is not necessarily a pure 0 value.

Yeah, I tried the same thing here and got the same results, I wonder what's the explanation. I simply inserted some pure silence there using Audacity, but I do get values in a quite small order of magnitude. So to detect them, instead of using...:

...
|
[tabread array1]
|
{abs]
|
[> 0]
|
[sel 1]
|
...

...I had to use:

...
|
[tabread array1]
|
{abs]
|
[> 0.001]
|
[sel 1]
|
...

Cheers!
Gilberto

Reply to Detecting first non silent sample index [COMPLETED] on Sat, 23 Jul 2016 15:28:05 GMT

pascal2000 — Sat, 23 Jul 2016 15:28:05 GMT

Thanks Gilberto. Following the same technic than yours, it is working. Great!

Reply to Detecting first non silent sample index [COMPLETED] on Sat, 23 Jul 2016 16:09:36 GMT

gsagostinho — Sat, 23 Jul 2016 16:09:36 GMT

My pleasure!