simplest way to write code to make sounds?
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From: The Natural Philosopher on 25 Dec 2009 04:56 pk wrote: > The Natural Philosopher wrote: > >> pk wrote: >>> The Natural Philosopher wrote: >>> >>>> For a debian linux system. >>>> >>>> I don't want the syntesizer bit..can take care of all that..just how to >>>> hook C or indeed any other language into making a noise come out of the >>>> speakers. >>>> >>>> Ideally would be a fragment of code that simply makes any noise on my >>>> ALSA based sound system. >>>> >>>> The only bit I found segfaults when it opens device 'default' >>> How about >>> >>> anything_that_produces_some_output > /dev/dsp >>> >>> (the noise that comes out of it is not very pretty though) >> OK, can you ( haha ) AMPLIFY on that a little? >> >> >> If I feed a bunch of bytes to that, are they simply buffered and spat >> out as a sequence of binary audio levels at 44Khz? >> >> If so, its just what I need. > > Not sure about the 44Khz part, but yeah, it just takes whatever you throw at > it as if it were something to play. > > About the "device or resource busy" thing, not sure, but it might be that > the device is being used exclusively by some process in the system > (typically things like arts, or gstreamer I think). At least I seem to > remember I had some similar problem in the past, although unfortunately I > can't really help you more. Ok. I downloaded two packages. Both use this to open a sound device in alsa. if ((err = snd_pcm_open (&playback_handle,"default", SND_PCM_STREAM_PLAYBACK, 0)) < 0) Both compile and link correctly. One runs, the other segfaults at this point. I conclude they aren't linking the same libraries.. ...ah. I found it. One had a later call to a library function that had changed from accepting a value, to a pointer. I have sounds.
From: The Natural Philosopher on 25 Dec 2009 05:24 In case anyone has the same problem, here is some code that opens a sound channel to ALSA. I didn't write it, I found it. #define ALSA_PCM_NEW_HW_PARAMS_API #include <alsa/asoundlib.h> snd_pcm_t *init_sound() { int rc; snd_pcm_t *handle; snd_pcm_hw_params_t *params; unsigned int val; int dir; snd_pcm_uframes_t frames; /* Open PCM device for playback. */ rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0); if (rc < 0) { fprintf(stderr, "unable to open pcm device: %s\n", snd_strerror(rc)); exit(1); } /* Allocate a hardware parameters object. */ snd_pcm_hw_params_alloca(¶ms); /* Fill it in with default values. */ snd_pcm_hw_params_any(handle, params); /* Set the desired hardware parameters. */ /* Interleaved mode */ snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED); /* Signed 16-bit little-endian format */ snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE); /* Two channels (stereo) */ snd_pcm_hw_params_set_channels(handle, params, 2); /* 44100 bits/second sampling rate (CD quality) */ val = (SAMPLE_FREQ); snd_pcm_hw_params_set_rate_near(handle, params, &val, &dir); /* Set period size to 1 frames. */ frames = 100000; snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir); /* Write the parameters to the driver */ rc = snd_pcm_hw_params(handle, params); if (rc < 0) { fprintf(stderr, "unable to set hw parameters: %s\n", snd_strerror(rc)); exit(1); } /* Use a buffer large enough to hold one period */ snd_pcm_hw_params_get_period_size(params, &frames,&dir); /* We want to loop for 5 seconds */ snd_pcm_hw_params_get_period_time(params,&val, &dir); return(handle); } To write a stereo pair of identical short words to it short value; int stereo; stereo=(value<<16) +value; snd_pcm_writei(handle, &stereo,1); This works in a loop. I.e. if value is set to e.g. the integer of sine (loop counter) you get a tone out. Perhaps I should have said I wanted a quick'n'dirty way to make noises for a possible sound effects board using a cheap microcontroller: First I need to develop the effect algorithms. PICS and the like do not have enough RAM to hold massive samples or .wavs. So algorithmic generation is what I needed. Once the sound is good enough, its down to PIC or equivalent with adequate processing power to generate it. It's been a long time since I wrote 'C' in any seriousness. Boy I am rusty..
From: Andreas Marschke on 3 Jan 2010 14:59
The Natural Philosopher wrote: > For a debian linux system. > > I don't want the syntesizer bit..can take care of all that..just how to > hook C or indeed any other language into making a noise come out of the > speakers. > > Ideally would be a fragment of code that simply makes any noise on my > ALSA based sound system. > > The only bit I found segfaults when it opens device 'default' How about a qt based application using Phonon there is plenty of really easy exambles to do musicish stuff with it and all the backend stuff is managed by phonon itself. |