ref: 3ccee2913529a7483062819543299eee681ec39a
parent: 57bb4de0f1d8279ffa115f9ff1c5d4d38d531f5c
author: Erik de Castro Lopo <erikd@mega-nerd.com>
date: Wed Nov 2 17:21:24 EDT 2011
examples/audio_out.[ch] : On Linux used ALSA instead of OSS when available.
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,9 @@
* configure.ac examples/Makefile.am
Detect ALSA and use it in varispeed-play.
+ * examples/audio_out.[ch]
+ On Linux used ALSA instead of OSS when available.
+
2011-08-15 Erik de Castro Lopo <erikd AT mega-nerd DOT com>
* configure.ac
--- a/examples/audio_out.c
+++ b/examples/audio_out.c
@@ -25,6 +25,13 @@
#include "audio_out.h"
+#if HAVE_ALSA_ASOUNDLIB_H
+ #define ALSA_PCM_NEW_HW_PARAMS_API
+ #define ALSA_PCM_NEW_SW_PARAMS_API
+ #include <alsa/asoundlib.h>
+ #include <sys/time.h>
+#endif
+
#if (HAVE_SNDFILE)
#include <float_cast.h>
@@ -36,129 +43,396 @@
#define MAKE_MAGIC(a,b,c,d,e,f,g,h) \
((a) + ((b) << 1) + ((c) << 2) + ((d) << 3) + ((e) << 4) + ((f) << 5) + ((g) << 6) + ((h) << 7))
+typedef struct AUDIO_OUT_s
+{ int magic ;+} AUDIO_OUT ;
+
+
/*------------------------------------------------------------------------------
-** Linux/OSS functions for playing a sound.
+** Linux (ALSA and OSS) functions for playing a sound.
*/
#if defined (__linux__)
+#if HAVE_ALSA_ASOUNDLIB_H
+
+#define ALSA_MAGIC MAKE_MAGIC ('L', 'n', 'x', '-', 'A', 'L', 'S', 'A')+
+typedef struct
+{ int magic ;+ snd_pcm_t * dev ;
+ int channels ;
+} ALSA_AUDIO_OUT ;
+
+static int alsa_write_float (snd_pcm_t *alsa_dev, float *data, int frames, int channels) ;
+
+static AUDIO_OUT *
+alsa_open (int channels, unsigned samplerate)
+{ ALSA_AUDIO_OUT *alsa_out ;+ const char * device = "default" ;
+ snd_pcm_hw_params_t *hw_params ;
+ snd_pcm_uframes_t buffer_size ;
+ snd_pcm_uframes_t alsa_period_size, alsa_buffer_frames ;
+ snd_pcm_sw_params_t *sw_params ;
+
+ int err ;
+
+ alsa_period_size = 1024 ;
+ alsa_buffer_frames = 4 * alsa_period_size ;
+
+ if ((alsa_out = calloc (1, sizeof (ALSA_AUDIO_OUT))) == NULL)
+ { perror ("alsa_open : malloc ") ;+ exit (1) ;
+ } ;
+
+ alsa_out->magic = ALSA_MAGIC ;
+ alsa_out->channels = channels ;
+
+ if ((err = snd_pcm_open (&alsa_out->dev, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0)
+ { fprintf (stderr, "cannot open audio device \"%s\" (%s)\n", device, snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ snd_pcm_nonblock (alsa_out->dev, 0) ;
+
+ if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0)
+ { fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_any (alsa_out->dev, hw_params)) < 0)
+ { fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_access (alsa_out->dev, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
+ { fprintf (stderr, "cannot set access type (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_format (alsa_out->dev, hw_params, SND_PCM_FORMAT_FLOAT)) < 0)
+ { fprintf (stderr, "cannot set sample format (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_rate_near (alsa_out->dev, hw_params, &samplerate, 0)) < 0)
+ { fprintf (stderr, "cannot set sample rate (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_channels (alsa_out->dev, hw_params, channels)) < 0)
+ { fprintf (stderr, "cannot set channel count (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_buffer_size_near (alsa_out->dev, hw_params, &alsa_buffer_frames)) < 0)
+ { fprintf (stderr, "cannot set buffer size (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params_set_period_size_near (alsa_out->dev, hw_params, &alsa_period_size, 0)) < 0)
+ { fprintf (stderr, "cannot set period size (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_hw_params (alsa_out->dev, hw_params)) < 0)
+ { fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ /* extra check: if we have only one period, this code won't work */
+ snd_pcm_hw_params_get_period_size (hw_params, &alsa_period_size, 0) ;
+ snd_pcm_hw_params_get_buffer_size (hw_params, &buffer_size) ;
+ if (alsa_period_size == buffer_size)
+ { fprintf (stderr, "Can't use period equal to buffer size (%lu == %lu)", alsa_period_size, buffer_size) ;+ goto catch_error ;
+ } ;
+
+ snd_pcm_hw_params_free (hw_params) ;
+
+ if ((err = snd_pcm_sw_params_malloc (&sw_params)) != 0)
+ { fprintf (stderr, "%s: snd_pcm_sw_params_malloc: %s", __func__, snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_sw_params_current (alsa_out->dev, sw_params)) != 0)
+ { fprintf (stderr, "%s: snd_pcm_sw_params_current: %s", __func__, snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ /* note: set start threshold to delay start until the ring buffer is full */
+ snd_pcm_sw_params_current (alsa_out->dev, sw_params) ;
+
+ if ((err = snd_pcm_sw_params_set_start_threshold (alsa_out->dev, sw_params, buffer_size)) < 0)
+ { fprintf (stderr, "cannot set start threshold (%s)\n", snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ if ((err = snd_pcm_sw_params (alsa_out->dev, sw_params)) != 0)
+ { fprintf (stderr, "%s: snd_pcm_sw_params: %s", __func__, snd_strerror (err)) ;+ goto catch_error ;
+ } ;
+
+ snd_pcm_sw_params_free (sw_params) ;
+
+ snd_pcm_reset (alsa_out->dev) ;
+
+catch_error :
+
+ if (err < 0 && alsa_out->dev != NULL)
+ { snd_pcm_close (alsa_out->dev) ;+ return NULL ;
+ } ;
+
+ return (AUDIO_OUT *) alsa_out ;
+} /* alsa_open */
+
+static void
+alsa_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{ static float buffer [BUFFER_LEN] ;+ ALSA_AUDIO_OUT *alsa_out ;
+ int read_frames ;
+
+ if ((alsa_out = (ALSA_AUDIO_OUT*) audio_out) == NULL)
+ { printf ("alsa_close : AUDIO_OUT is NULL.\n") ;+ return ;
+ } ;
+
+ if (alsa_out->magic != ALSA_MAGIC)
+ { printf ("alsa_close : Bad magic number.\n") ;+ return ;
+ } ;
+
+ while ((read_frames = callback (callback_data, buffer, BUFFER_LEN / alsa_out->channels)))
+ alsa_write_float (alsa_out->dev, buffer, read_frames, alsa_out->channels) ;
+
+ return ;
+} /* alsa_play */
+
+static int
+alsa_write_float (snd_pcm_t *alsa_dev, float *data, int frames, int channels)
+{ static int epipe_count = 0 ;+
+ int total = 0 ;
+ int retval ;
+
+ if (epipe_count > 0)
+ epipe_count -- ;
+
+ while (total < frames)
+ { retval = snd_pcm_writei (alsa_dev, data + total * channels, frames - total) ;+
+ if (retval >= 0)
+ { total += retval ;+ if (total == frames)
+ return total ;
+
+ continue ;
+ } ;
+
+ switch (retval)
+ { case -EAGAIN :+ puts ("alsa_write_float: EAGAIN") ;+ continue ;
+ break ;
+
+ case -EPIPE :
+ if (epipe_count > 0)
+ { printf ("alsa_write_float: EPIPE %d\n", epipe_count) ;+ if (epipe_count > 140)
+ return retval ;
+ } ;
+ epipe_count += 100 ;
+
+#if 0
+ if (0)
+ { snd_pcm_status_t *status ;+
+ snd_pcm_status_alloca (&status) ;
+ if ((retval = snd_pcm_status (alsa_dev, status)) < 0)
+ fprintf (stderr, "alsa_out: xrun. can't determine length\n") ;
+ else if (snd_pcm_status_get_state (status) == SND_PCM_STATE_XRUN)
+ { struct timeval now, diff, tstamp ;+
+ gettimeofday (&now, 0) ;
+ snd_pcm_status_get_trigger_tstamp (status, &tstamp) ;
+ timersub (&now, &tstamp, &diff) ;
+
+ fprintf (stderr, "alsa_write_float xrun: of at least %.3f msecs. resetting stream\n",
+ diff.tv_sec * 1000 + diff.tv_usec / 1000.0) ;
+ }
+ else
+ fprintf (stderr, "alsa_write_float: xrun. can't determine length\n") ;
+ } ;
+#endif
+
+ snd_pcm_prepare (alsa_dev) ;
+ break ;
+
+ case -EBADFD :
+ fprintf (stderr, "alsa_write_float: Bad PCM state.n") ;
+ return 0 ;
+ break ;
+
+ case -ESTRPIPE :
+ fprintf (stderr, "alsa_write_float: Suspend event.n") ;
+ return 0 ;
+ break ;
+
+ case -EIO :
+ puts ("alsa_write_float: EIO") ;+ return 0 ;
+
+ default :
+ fprintf (stderr, "alsa_write_float: retval = %d\n", retval) ;
+ return 0 ;
+ break ;
+ } ; /* switch */
+ } ; /* while */
+
+ return total ;
+} /* alsa_write_float */
+
+static void
+alsa_close (AUDIO_OUT *audio_out)
+{ ALSA_AUDIO_OUT *alsa_out ;+
+ if ((alsa_out = (ALSA_AUDIO_OUT*) audio_out) == NULL)
+ { printf ("alsa_close : AUDIO_OUT is NULL.\n") ;+ return ;
+ } ;
+
+ if (alsa_out->magic != ALSA_MAGIC)
+ { printf ("alsa_close : Bad magic number.\n") ;+ return ;
+ } ;
+
+ memset (alsa_out, 0, sizeof (ALSA_AUDIO_OUT)) ;
+
+ free (alsa_out) ;
+
+ return ;
+} /* alsa_close */
+
+#endif /* HAVE_ALSA_ASOUNDLIB_H */
+
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>
-#define LINUX_MAGIC MAKE_MAGIC ('L', 'i', 'n', 'u', 'x', 'O', 'S', 'S')+#define OSS_MAGIC MAKE_MAGIC ('L', 'i', 'n', 'u', 'x', 'O', 'S', 'S')typedef struct
{ int magic ;int fd ;
int channels ;
-} LINUX_AUDIO_OUT ;
+} OSS_AUDIO_OUT ;
-static AUDIO_OUT *linux_open (int channels, int samplerate) ;
-static void linux_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
-static void linux_close (AUDIO_OUT *audio_out) ;
+static AUDIO_OUT *opensoundsys_open (int channels, int samplerate) ;
+static void opensoundsys_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
+static void opensoundsys_close (AUDIO_OUT *audio_out) ;
static AUDIO_OUT *
-linux_open (int channels, int samplerate)
-{ LINUX_AUDIO_OUT *linux_out ;+opensoundsys_open (int channels, int samplerate)
+{ OSS_AUDIO_OUT *opensoundsys_out ;int stereo, fmt, error ;
- if ((linux_out = malloc (sizeof (LINUX_AUDIO_OUT))) == NULL)
- { perror ("linux_open : malloc ") ;+ if ((opensoundsys_out = calloc (1, sizeof (OSS_AUDIO_OUT))) == NULL)
+ { perror ("opensoundsys_open : malloc ") ;exit (1) ;
} ;
- linux_out->magic = LINUX_MAGIC ;
- linux_out->channels = channels ;
+ opensoundsys_out->magic = OSS_MAGIC ;
+ opensoundsys_out->channels = channels ;
- if ((linux_out->fd = open ("/dev/dsp", O_WRONLY, 0)) == -1)- { perror ("linux_open : open ") ;+ if ((opensoundsys_out->fd = open ("/dev/dsp", O_WRONLY, 0)) == -1)+ { perror ("opensoundsys_open : open ") ;exit (1) ;
} ;
stereo = 0 ;
- if (ioctl (linux_out->fd, SNDCTL_DSP_STEREO, &stereo) == -1)
+ if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_STEREO, &stereo) == -1)
{ /* Fatal error */- perror ("linux_open : stereo ") ;+ perror ("opensoundsys_open : stereo ") ;exit (1) ;
} ;
- if (ioctl (linux_out->fd, SNDCTL_DSP_RESET, 0))
- { perror ("linux_open : reset ") ;+ if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_RESET, 0))
+ { perror ("opensoundsys_open : reset ") ;exit (1) ;
} ;
fmt = CPU_IS_BIG_ENDIAN ? AFMT_S16_BE : AFMT_S16_LE ;
- if (ioctl (linux_out->fd, SNDCTL_DSP_SETFMT, &fmt) != 0)
- { perror ("linux_open_dsp_device : set format ") ;+ if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_SETFMT, &fmt) != 0)
+ { perror ("opensoundsys_open_dsp_device : set format ") ;exit (1) ;
} ;
- if ((error = ioctl (linux_out->fd, SNDCTL_DSP_CHANNELS, &channels)) != 0)
- { perror ("linux_open : channels ") ;+ if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_CHANNELS, &channels)) != 0)
+ { perror ("opensoundsys_open : channels ") ;exit (1) ;
} ;
- if ((error = ioctl (linux_out->fd, SNDCTL_DSP_SPEED, &samplerate)) != 0)
- { perror ("linux_open : sample rate ") ;+ if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_SPEED, &samplerate)) != 0)
+ { perror ("opensoundsys_open : sample rate ") ;exit (1) ;
} ;
- if ((error = ioctl (linux_out->fd, SNDCTL_DSP_SYNC, 0)) != 0)
- { perror ("linux_open : sync ") ;+ if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_SYNC, 0)) != 0)
+ { perror ("opensoundsys_open : sync ") ;exit (1) ;
} ;
- return (AUDIO_OUT*) linux_out ;
-} /* linux_open */
+ return (AUDIO_OUT*) opensoundsys_out ;
+} /* opensoundsys_open */
static void
-linux_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
-{ LINUX_AUDIO_OUT *linux_out ;+opensoundsys_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{ OSS_AUDIO_OUT *opensoundsys_out ;static float float_buffer [BUFFER_LEN] ;
static short buffer [BUFFER_LEN] ;
- int k, readcount ;
+ int k, read_frames ;
- if ((linux_out = (LINUX_AUDIO_OUT*) audio_out) == NULL)
- { printf ("linux_play : AUDIO_OUT is NULL.\n") ;+ if ((opensoundsys_out = (OSS_AUDIO_OUT*) audio_out) == NULL)
+ { printf ("opensoundsys_play : AUDIO_OUT is NULL.\n") ;return ;
} ;
- if (linux_out->magic != LINUX_MAGIC)
- { printf ("linux_play : Bad magic number.\n") ;+ if (opensoundsys_out->magic != OSS_MAGIC)
+ { printf ("opensoundsys_play : Bad magic number.\n") ;return ;
} ;
- while ((readcount = callback (callback_data, float_buffer, BUFFER_LEN / linux_out->channels)))
- { for (k = 0 ; k < readcount * linux_out->channels ; k++)+ while ((read_frames = callback (callback_data, float_buffer, BUFFER_LEN / opensoundsys_out->channels)))
+ { for (k = 0 ; k < read_frames * opensoundsys_out->channels ; k++)buffer [k] = lrint (32767.0 * float_buffer [k]) ;
- (void) write (linux_out->fd, buffer, readcount * linux_out->channels * sizeof (short)) ;
+ (void) write (opensoundsys_out->fd, buffer, read_frames * opensoundsys_out->channels * sizeof (short)) ;
} ;
return ;
-} /* linux_play */
+} /* opensoundsys_play */
static void
-linux_close (AUDIO_OUT *audio_out)
-{ LINUX_AUDIO_OUT *linux_out ;+opensoundsys_close (AUDIO_OUT *audio_out)
+{ OSS_AUDIO_OUT *opensoundsys_out ;- if ((linux_out = (LINUX_AUDIO_OUT*) audio_out) == NULL)
- { printf ("linux_close : AUDIO_OUT is NULL.\n") ;+ if ((opensoundsys_out = (OSS_AUDIO_OUT*) audio_out) == NULL)
+ { printf ("opensoundsys_close : AUDIO_OUT is NULL.\n") ;return ;
} ;
- if (linux_out->magic != LINUX_MAGIC)
- { printf ("linux_close : Bad magic number.\n") ;+ if (opensoundsys_out->magic != OSS_MAGIC)
+ { printf ("opensoundsys_close : Bad magic number.\n") ;return ;
} ;
- memset (linux_out, 0, sizeof (LINUX_AUDIO_OUT)) ;
+ memset (opensoundsys_out, 0, sizeof (OSS_AUDIO_OUT)) ;
- free (linux_out) ;
+ free (opensoundsys_out) ;
return ;
-} /* linux_close */
+} /* opensoundsys_close */
#endif /* __linux__ */
@@ -206,7 +480,7 @@
OSStatus err ;
size_t count ;
- if ((macosx_out = malloc (sizeof (MACOSX_AUDIO_OUT))) == NULL)
+ if ((macosx_out = calloc (1, sizeof (MACOSX_AUDIO_OUT))) == NULL)
{ perror ("macosx_open : malloc ") ;exit (1) ;
} ;
@@ -417,7 +691,7 @@
WAVEFORMATEX wf ;
int error ;
- if ((win32_out = malloc (sizeof (WIN32_AUDIO_OUT))) == NULL)
+ if ((win32_out = calloc (1, sizeof (WIN32_AUDIO_OUT))) == NULL)
{ perror ("win32_open : malloc ") ;exit (1) ;
} ;
@@ -619,7 +893,7 @@
audio_info_t audio_info ;
int error ;
- if ((solaris_out = malloc (sizeof (SOLARIS_AUDIO_OUT))) == NULL)
+ if ((solaris_out = calloc (1, sizeof (SOLARIS_AUDIO_OUT))) == NULL)
{ perror ("solaris_open : malloc ") ;exit (1) ;
} ;
@@ -657,7 +931,7 @@
{ SOLARIS_AUDIO_OUT *solaris_out ;static float float_buffer [BUFFER_LEN] ;
static short buffer [BUFFER_LEN] ;
- int k, readcount ;
+ int k, read_frames ;
if ((solaris_out = (SOLARIS_AUDIO_OUT*) audio_out) == NULL)
{ printf ("solaris_play : AUDIO_OUT is NULL.\n") ;@@ -669,10 +943,10 @@
return ;
} ;
- while ((readcount = callback (callback_data, float_buffer, BUFFER_LEN / solaris_out->channels)))
- { for (k = 0 ; k < readcount * solaris_out->channels ; k++)+ while ((read_frames = callback (callback_data, float_buffer, BUFFER_LEN / solaris_out->channels)))
+ { for (k = 0 ; k < read_frames * solaris_out->channels ; k++)buffer [k] = lrint (32767.0 * float_buffer [k]) ;
- write (solaris_out->fd, buffer, readcount * solaris_out->channels * sizeof (short)) ;
+ write (solaris_out->fd, buffer, read_frames * solaris_out->channels * sizeof (short)) ;
} ;
return ;
@@ -709,7 +983,11 @@
audio_open (int channels, int samplerate)
{#if defined (__linux__)
- return linux_open (channels, samplerate) ;
+ #if HAVE_ALSA_ASOUNDLIB_H
+ if (access ("/proc/asound/cards", R_OK) == 0)+ return alsa_open (channels, samplerate) ;
+ #endif
+ return opensoundsys_open (channels, samplerate) ;
#elif (defined (__MACH__) && defined (__APPLE__))
return macosx_open (channels, samplerate) ;
#elif (defined (sun) && defined (unix))
@@ -747,7 +1025,11 @@
} ;
#if defined (__linux__)
- linux_play (callback, audio_out, callback_data) ;
+ #if HAVE_ALSA_ASOUNDLIB_H
+ if (audio_out->magic == ALSA_MAGIC)
+ alsa_play (callback, audio_out, callback_data) ;
+ #endif
+ opensoundsys_play (callback, audio_out, callback_data) ;
#elif (defined (__MACH__) && defined (__APPLE__))
macosx_play (callback, audio_out, callback_data) ;
#elif (defined (sun) && defined (unix))
@@ -768,7 +1050,11 @@
audio_close (AUDIO_OUT *audio_out)
{#if defined (__linux__)
- linux_close (audio_out) ;
+ #if HAVE_ALSA_ASOUNDLIB_H
+ if (audio_out->magic == ALSA_MAGIC)
+ alsa_close (audio_out) ;
+ #endif
+ opensoundsys_close (audio_out) ;
#elif (defined (__MACH__) && defined (__APPLE__))
macosx_close (audio_out) ;
#elif (defined (sun) && defined (unix))
--- a/examples/audio_out.h
+++ b/examples/audio_out.h
@@ -16,22 +16,20 @@
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
-typedef void AUDIO_OUT ;
+typedef struct AUDIO_OUT_s AUDIO_OUT ;
typedef int (*get_audio_callback_t) (void *callback_data, float *samples, int frames) ;
-/* A general audio ooutput function (Linux/OSS, Win32, MacOSX, Solaris)
-** which retrieves data using the callback function in the above struct.
+/* A general audio output function (Linux/ALSA, Linux/OSS, Win32, MacOSX,
+** Solaris) which retrieves data using the callback function in the above
+** struct.
**
** audio_open - opens the device and returns an anonymous pointer to its
** own private data.
*/
-
-
AUDIO_OUT *audio_open (int channels, int samplerate) ;
void audio_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
void audio_close (AUDIO_OUT *audio_data) ;
-