topic Re: Cut the first impulse in LabVIEW

Cut the first impulse

Kirin_Jindosh — Mon, 06 May 2024 08:31:12 GMT

Hello. I have 2 .wav files with pulses from which I need to cut the first pulse so that it is the same length. My solution can only cut a given fragment (that is, find the necessary parameters by touch so that it cuts a specific fragment). Is it possible to implement this somehow differently? I think it’s hardly possible to achieve such accuracy manually

Здравствуйте. У меня есть 2 Вав файла с импульсами из которых нужно вырезать первый импульс чтобы он был одинаковой длинны. Мое решение может вырезать только заданный фрагмент (тоесть наощуп найти нужные параметры, чтобы оно вырезало определенный фрагмент). Может можно как-то иначе это реализовать ? Вручную добиться такой точности думаю вряд-ли возможно

Re: Cut the first impulse

billko — Mon, 06 May 2024 08:36:17 GMT

@Kirin_Jindosh wrote:

Hello. I have 2 .wav files with pulses from which I need to cut the first pulse so that it is the same length. My solution can only cut a given fragment (that is, find the necessary parameters by touch so that it cuts a specific fragment). Is it possible to implement this somehow differently? I think it’s hardly possible to achieve such accuracy manually

Здравствуйте. У меня есть 2 Вав файла с импульсами из которых нужно вырезать первый импульс чтобы он был одинаковой длинны. Мое решение может вырезать только заданный фрагмент (тоесть наощуп найти нужные параметры, чтобы оно вырезало определенный фрагмент). Может можно как-то иначе это реализовать ? Вручную добиться такой точности думаю вряд-ли возможно

I don't understand. Media editors can manipulate a waveform to the individual sample. That should be accurate enough. Maybe that's not what you're asking?

Re: Cut the first impulse

Kirin_Jindosh — Mon, 06 May 2024 09:12:18 GMT

Have you watched my program? There, in order to cut a fragment, you need to manually search, which is not very convenient and accurate. I need to specifically cut out the first pulse so that it matches the length of the first pulse of another audio file.

Re: Cut the first impulse

Yamaeda — Mon, 06 May 2024 10:48:09 GMT

You can e.g. use the Threshold 1D array to find the start of your pulse and then use that index in the other.

Re: Cut the first impulse

Kirin_Jindosh — Mon, 06 May 2024 13:49:28 GMT

So it’s for an array of numbers, but I need it for audio. Well, or I don’t know how to connect it

Re: Cut the first impulse

GerdW — Mon, 06 May 2024 15:02:36 GMT

Hi Kirin,

@Kirin_Jindosh wrote:

So it’s for an array of numbers, but I need it for audio.

"Audio" aka waveforms basically are just arrays of numbers!

Mind to share your VI downconverted to LV2021 or older? (I prefer LV2019.)

Re: Cut the first impulse

Kirin_Jindosh — Mon, 06 May 2024 15:05:11 GMT

Certainly can. I hope it was preserved correctly)

Re: Cut the first impulse

GerdW — Mon, 06 May 2024 17:35:48 GMT

Hi Lirin,

thanks for conversion!

On your signals:

filter the noise: there seems to be some noise with levels <0.1
then search the resulting filtered signal for values above noise level: it's quite easy to find the pulses…

Re: Cut the first impulse

Kirin_Jindosh — Mon, 06 May 2024 21:50:41 GMT

Sorry, but could you tell me or show me how to do this?

Re: Cut the first impulse

GerdW — Tue, 07 May 2024 05:42:09 GMT

Hi Kirin,

@Kirin_Jindosh wrote:

Sorry, but could you tell me or show me how to do this?

Get the Y array of the waveform, compare with ">0.2" and search for the first TRUE in the resulting boolean array.

This is a very simple approach, based on the waveforms in your first message. You may apply some filtering when there could be more noise in the signals…