[REBOL] Re: Determining the length of a sound before playing it
From: rebolek:gmai:l at: 31-Aug-2009 20:54
Hi Steven,
the lenght of the sound is:
(length in bytes) / (sampling frequency) / (sampling resolution in bytes) /
(number of channels) = length of the sound
This is for RAW sounds. For WAV/AIFF add header size, for MP3 you have to
use some MP3 analyzer (I think someone did it in REBOL).
So for example a stereo sound that is 176400 bytes long and is sampled at
44100kHz in 16bit it is:
176400 / 44100 / 2 / 2 = 1 second.
Hope that helps,
Bolek
On Mon, Aug 31, 2009 at 7:23 PM, Steven White
<swhite-ci.bloomington.mn.us>wrote:
> REBOL/View Pro will play a sound. I have done that. Does anyone know if
> it is possible for a REBOL program to determine the length of a sound before
> playing it?
>
> Last night my spouse was struggling with Power Point to make a slide show
> with background music. The reason it was such a struggle seemed to be that
> it was hard to find the settings to make that happen, and when we found some
> settings that APPEARED to be the ones that SHOULD make that happen, it still
> did NOT happen. Defeated by complexity.
>
> That got me thinking that it should be logically simple to make a program
> that does only one thing, namely, display pictures with background music.
>
> Determine length of music.
> Obtain list of all pictures in a directory.
> Determine number of pictures.
> Divide length of music by number of pictures, giving duration.
> Start sound playing.
> For each picture,
> Display the picture
> Wait for the duration.
> Quit
> (Details are left as an exercise, as they say.)
>
> All those steps I have seen done in various sample REBOL scripts, except
> for the first one of finding out how long a sound will play.
>
> Thank you.
>
> Steven White
> City of Bloomington
> 1800 W Old Shakopee Rd
> Bloomington MN 55431-3096
> USA
> 952-563-4882 (voice)
> 952-563-4672 (fax)
> steven.white-ci.bloomington.mn.us
>
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Boleslav Březovský
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