DELPHI AREA Forum

Hello. Thank you for the Wave Package - I use it a lot.

But now I have stumbled with cropping a wave loaded into TWave with a 1 sample accuracy. TWave.Delete takes a Pos argument in milliseconds and that provides only 44 sample resolution for 44100Hz audio stream. How can I delete, say, from 2000th sample to the end of file?

BTW, I didn't understand completely what is TWave.Crop intended for.

Thanks.

To delete end of a wave audio from a position specified by the Pos variable use:

Wave.Delete(Pos, Wave.Length - Pos);

Consider that converting milliseconds to samples is approximated.

Regarding Crop method, suppose in a stream there is a wave audio appended with some other data, the Crop method removes the non-audio data.

Kambiz wrote:Consider that converting milliseconds to samples is approximated.

Dear Kambiz, I need to specify EXACT sample number, not approximated. If we have 44100 samples per second, that is approx. 44 samples per a millisecond. As I understood, Delete(1,1) corresponds to deleting 44 samples from offset 44. I'd rather have function that take sample numbers as arguments.

Example: to delete 50 samples from sample number 100.

It means changing the average samples per second, and implies changing the wave format.

It doesn't mean changing the average samples per second. For instance, if delete 1 sample from the beginning of the wave, how does it affects wave description? In no way. I just have deleted 0,023ms of sound.

Let me restate my request - the current realization is tailored to work with 1ms precision, while I want to manipulate wave with 1 sample precision.

I though about working with underlying TMemoryStream directly, but then I need somehow to update TWave fileds to reflect that changes. It seems to me not easier then bothering with Windows API functions without TWave class at all.

If you look at Delete code, you will find out how to change wave data directly. It's easier to subclass TWave and introduce a new delete method for your purpose.