gstreamer/ext/alsa/gstalsa.h

/*
 * Copyright (C) 2001 CodeFactory AB
 * Copyright (C) 2001 Thomas Nyberg <thomas@codefactory.se>
 * Copyright (C) 2001-2002 Andy Wingo <apwingo@eos.ncsu.edu>
 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef __GST_ALSA_H__
#define __GST_ALSA_H__

#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API

#include <alsa/asoundlib.h>
#include <gst/gst.h>


GST_DEBUG_CATEGORY_EXTERN (alsa_debug);
#define GST_CAT_DEFAULT alsa_debug


/* error checking for standard alsa functions */
/* NOTE: these functions require a GObject *this and can only be used in 
   functions that return TRUE on success and FALSE on error */
#define SIMPLE_ERROR_CHECK(value) G_STMT_START{ \
  int err = (value); if (err < 0) { return FALSE; } \
}G_STMT_END


#ifdef G_HAVE_ISO_VARARGS
#define ERROR_CHECK(value, ...) G_STMT_START{ \
  int err = (value); \
  if (err < 0) { \
    GST_WARNING_OBJECT (this, __VA_ARGS__, snd_strerror (err)); \
    return FALSE; \
  } \
}G_STMT_END

#elif defined(G_HAVE_GNUC_VARARGS)
#define ERROR_CHECK(value, args...) G_STMT_START{ \
  int err = (value); \
  if (err < 0) { \
    GST_WARNING_OBJECT (this, ## args, snd_strerror (err)); \
    return FALSE; \
  } \
}G_STMT_END

#else
#define ERROR_CHECK(value, args...) G_STMT_START{ \
  int err = (value); \
  if (err < 0) { \
    GST_WARNING_OBJECT (this, snd_strerror (err)); \
    return FALSE; \
  } \
}G_STMT_END
#endif


#define GST_ALSA_MIN_RATE	8000
#define GST_ALSA_MAX_RATE	192000
#define GST_ALSA_MAX_TRACKS	64	/* we don't support more than 64 tracks */
#define GST_ALSA_MAX_CHANNELS	32	/* tracks can have up to 32 channels */

/* Mono is 1 channel ; the 5.1 standard is 6 channels. The value for
   GST_ALSA_MAX_CHANNELS comes from alsa/mixer.h. */

/* Max allowed discontinuity in time units between timestamp and playback
   pointer before killing/inserting samples. This should be big enough to allow
   smoothing errors on different video formats. */
#define GST_ALSA_DEFAULT_DISCONT (GST_SECOND / 10)

G_BEGIN_DECLS
#define GST_ALSA(obj)			(G_TYPE_CHECK_INSTANCE_CAST(obj, GST_TYPE_ALSA, GstAlsa))
#define GST_ALSA_CLASS(klass)		(G_TYPE_CHECK_CLASS_CAST(klass, GST_TYPE_ALSA, GstAlsaClass))
#define GST_ALSA_GET_CLASS(obj)		(G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_ALSA, GstAlsaClass))
#define GST_IS_ALSA(obj)		(G_TYPE_CHECK_INSTANCE_TYPE(obj, GST_TYPE_ALSA))
#define GST_IS_ALSA_CLASS(klass)	(G_TYPE_CHECK_CLASS_TYPE(klass, GST_TYPE_ALSA))
#define GST_TYPE_ALSA			(gst_alsa_get_type())
    enum
{
  GST_ALSA_OPEN = GST_ELEMENT_FLAG_LAST,
  GST_ALSA_RUNNING,
  GST_ALSA_CAPS_NEGO,
  GST_ALSA_FLAG_LAST = GST_ELEMENT_FLAG_LAST + 3,
};

typedef enum
{
  GST_ALSA_CAPS_PAUSE = 0,
  GST_ALSA_CAPS_RESUME,
  GST_ALSA_CAPS_SYNC_START
      /* add more */
} GstAlsaPcmCaps;

#define GST_ALSA_CAPS_IS_SET(obj, flag) (GST_ALSA (obj)->pcm_caps & (1<<(flag)))
#define GST_ALSA_CAPS_SET(obj, flag, set) G_STMT_START{  \
  if (set) { (GST_ALSA (obj)->pcm_caps |=  (1<<(flag))); } \
  else     { (GST_ALSA (obj)->pcm_caps &= ~(1<<(flag))); } \
}G_STMT_END

typedef struct _GstAlsaClock GstAlsaClock;
typedef struct _GstAlsaClockClass GstAlsaClockClass;

typedef struct _GstAlsa GstAlsa;
typedef struct _GstAlsaClass GstAlsaClass;

typedef int (*GstAlsaTransmitFunction) (GstAlsa * this,
    snd_pcm_sframes_t * avail);

typedef struct
{
  snd_pcm_format_t format;
  guint rate;
  gint channels;
} GstAlsaFormat;

struct _GstAlsa
{
  GstElement parent;

  /* array of GstAlsaPads */
  GstPad *pad[GST_ALSA_MAX_TRACKS];

  gchar *device;
  snd_pcm_t *handle;
  snd_pcm_info_t *info;
  guint pcm_caps;		/* capabilities of the pcm device, see GstAlsaPcmCaps */
  snd_output_t *out;

  GstAlsaFormat *format;	/* NULL if undefined */
  gboolean mmap;		/* use mmap transmit (fast) or read/write (sloooow) */
  GstAlsaTransmitFunction transmit;

  /* latency / performance parameters */
  snd_pcm_uframes_t period_size;
  unsigned int period_count;

  gboolean autorecover;

  /* clocking */
  GstAlsaClock *clock;		/* our provided clock */
  snd_pcm_uframes_t transmitted;	/* samples transmitted since last sync 
					   This thing actually is our master clock.
					   We will event insert silent samples or
					   drop some to sync to incoming timestamps.
					 */
  GstClockTime max_discont;	/* max difference between current
				   playback timestamp and buffers timestamps
				 */
};

struct _GstAlsaClass
{
  GstElementClass parent_class;

  snd_pcm_stream_t stream;

  /* different transmit functions */
  GstAlsaTransmitFunction transmit_mmap;
  GstAlsaTransmitFunction transmit_rw;

  /* autodetected devices available */
  GList *devices;
};

GType gst_alsa_get_type (void);

void gst_alsa_set_eos (GstAlsa * this);
GstPadLinkReturn gst_alsa_link (GstPad * pad, const GstCaps * caps);
GstCaps *gst_alsa_get_caps (GstPad * pad);
GstCaps *gst_alsa_fixate (GstPad * pad, const GstCaps * caps);
GstCaps *gst_alsa_caps (snd_pcm_format_t format, gint rate, gint channels);

/* audio processing functions */
inline snd_pcm_sframes_t gst_alsa_update_avail (GstAlsa * this);
inline gboolean gst_alsa_pcm_wait (GstAlsa * this);
inline gboolean gst_alsa_start (GstAlsa * this);
gboolean gst_alsa_xrun_recovery (GstAlsa * this);

/* format conversions */
inline snd_pcm_uframes_t gst_alsa_timestamp_to_samples (GstAlsa * this,
    GstClockTime time);
inline GstClockTime gst_alsa_samples_to_timestamp (GstAlsa * this,
    snd_pcm_uframes_t samples);
inline snd_pcm_uframes_t gst_alsa_bytes_to_samples (GstAlsa * this,
    guint bytes);
inline guint gst_alsa_samples_to_bytes (GstAlsa * this,
    snd_pcm_uframes_t samples);
inline GstClockTime gst_alsa_bytes_to_timestamp (GstAlsa * this, guint bytes);
inline guint gst_alsa_timestamp_to_bytes (GstAlsa * this, GstClockTime time);

G_END_DECLS
#endif /* __GST_ALSA_H__ */