How to get (milli)seconds from al_get_sample

How to get (milli)seconds from al_get_sample_length()?

TeaRDoWN

Member #8,518

April 2007

How do I get seconds or milliseconds from al_get_sample_length()? My ~1s sample return ~6600. I guess the value needs to be divided...or?

A5 examples or demos does not cover this.

raynebc

Member #11,908

May 2010

My guess would be to obtain the sample frequency (al_get_sample_instance_frequency) and the number of channels (al_get_channel_count). The frequency is the number of samples per second per channel, so you should be able to find the length in milliseconds with:

length = al_get_sample_length(sample) / al_get_channel_count(sample) / al_get_sample_instance_frequency(sample);

Thomas Fjellstrom

Member #476

June 2000

That might also need to take into account stereo samples, you would then need to divide by two.

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Trent Gamblin

Member #261

April 2000

That'll give you the length in seconds, multiply by 1000 to get milliseconds. The channel count is the stereo part, it'll be 2 for a stereo sample.

TeaRDoWN

Member #8,518

April 2007

al_get_channel_count() or does not take a ALLEGRO_SOUND as parameter. Did you mean that function or al_get_sample_channels()?

al_get_sample_length(sound) = 5641
al_get_sample_channels(sound) = 16
al_get_sample_frequency(sound) = 11025

length / channels / frequency = 0,032

Actual sound length is according to Window Movie Maker 0,5s.

length / frequency = 0,51

Oscar Giner

Member #2,207

April 2002

TeaRDoWN said:

al_get_sample_channels(sound) = 16

The value returned by al_get_sample_channels is not the number of channels directly, but one of these constants:

ALLEGRO_CHANNEL_CONF_1
ALLEGRO_CHANNEL_CONF_2
ALLEGRO_CHANNEL_CONF_3
ALLEGRO_CHANNEL_CONF_4
ALLEGRO_CHANNEL_CONF_5_1
ALLEGRO_CHANNEL_CONF_6_1
ALLEGRO_CHANNEL_CONF_7_1

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TeaRDoWN

Member #8,518

April 2007

Yes, but I just tried to figure out which function raynebc wanted me to use when he wrote al_get_channel_count(sample).

raynebc

Member #11,908

May 2010

Off the top of my head, I don't know which function you should use, but whichever one directly returns the number of channels instead of a macro defined value. I did forget to mention dividing by 1000.