ao_alsa.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

/*
  ao_alsa9/1.x - ALSA-0.9.x-1.x output plugin for MPlayer

  (C) Alex Beregszaszi
  
  modified for real alsa-0.9.0-support by Zsolt Barat <[e-mail]>
  additional AC3 passthrough support by Andy Lo A Foe <[e-mail]>  
  08/22/2002 iec958-init rewritten and merged with common init, zsolt
  04/13/2004 merged with ao_alsa1.x, fixes provided by Jindrich Makovicka
  04/25/2004 printfs converted to mp_msg, Zsolt.
  
  Any bugreports regarding to this driver are welcome.
*/

#include <errno.h>
#include <sys/time.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <sys/poll.h>

#include "config.h"
#include "subopt-helper.h"
#include "mixer.h"
#include "mp_msg.h"

#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API

#if HAVE_SYS_ASOUNDLIB_H
#include <sys/asoundlib.h>
#elif HAVE_ALSA_ASOUNDLIB_H
#include <alsa/asoundlib.h>
#else
#error "asoundlib.h is not in sys/ or alsa/ - please bugreport"
#endif


#include "audio_out.h"
#include "audio_out_internal.h"
#include "libaf/af_format.h"

static ao_info_t info = 
{
    "ALSA-0.9.x-1.x audio output",
    "alsa",
    "Alex Beregszaszi, Zsolt Barat <[e-mail]>",
    "under developement"
};

LIBAO_EXTERN(alsa)

static snd_pcm_t *alsa_handler;
static snd_pcm_format_t alsa_format;
static snd_pcm_hw_params_t *alsa_hwparams;
static snd_pcm_sw_params_t *alsa_swparams;

/* possible 4096, original 8192 
 * was only needed for calculating chunksize? */
static int alsa_fragsize = 4096;
/* 16 sets buffersize to 16 * chunksize is as default 1024
 * which seems to be good avarge for most situations 
 * so buffersize is 16384 frames by default */
static int alsa_fragcount = 16;
static snd_pcm_uframes_t chunk_size = 1024;//is alsa_fragsize / 4

#define MIN_CHUNK_SIZE 1024

static size_t bits_per_sample, bytes_per_sample, bits_per_frame;
static size_t chunk_bytes;

int ao_mmap = 0;
int ao_noblock = 0;
int first = 1;

static int open_mode;
static int set_block_mode;
static int alsa_can_pause = 0;

#define ALSA_DEVICE_SIZE 256

#undef BUFFERTIME
#define SET_CHUNKSIZE
#undef USE_POLL

/* to set/get/query special features/parameters */
static int control(int cmd, void *arg)
{
  switch(cmd) {
  case AOCONTROL_QUERY_FORMAT:
    return CONTROL_TRUE;
#ifndef WORDS_BIGENDIAN 
  case AOCONTROL_GET_VOLUME:
  case AOCONTROL_SET_VOLUME:
    {
      ao_control_vol_t *vol = (ao_control_vol_t *)arg;

      int err;
      snd_mixer_t *handle;
      snd_mixer_elem_t *elem;
      snd_mixer_selem_id_t *sid;

      static char *mix_name = "PCM";
      static char *card = "default";
      static int mix_index = 0;

      long pmin, pmax;
      long get_vol, set_vol;
      float f_multi;

      if(mixer_channel) {
	 char *test_mix_index;

	 mix_name = strdup(mixer_channel);
	 if (test_mix_index = strchr(mix_name, ',')){
		*test_mix_index = 0;
		test_mix_index++;
		mix_index = strtol(test_mix_index, &test_mix_index, 0);

		if (*test_mix_index){
		  mp_msg(MSGT_AO,MSGL_ERR,
		    "alsa-control: invalid mixer index. Defaulting to 0\n");
		  mix_index = 0 ;
		}
	 }
      }
      if(mixer_device) card = mixer_device;

      if(ao_data.format == AF_FORMAT_AC3)
	return CONTROL_TRUE;

      //allocate simple id
      snd_mixer_selem_id_alloca(&sid);
	
      //sets simple-mixer index and name
      snd_mixer_selem_id_set_index(sid, mix_index);
      snd_mixer_selem_id_set_name(sid, mix_name);

      if (mixer_channel) {
	free(mix_name);
	mix_name = NULL;
      }

      if ((err = snd_mixer_open(&handle, 0)) < 0) {
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: mixer open error: %s\n", snd_strerror(err));
	return CONTROL_ERROR;
      }

      if ((err = snd_mixer_attach(handle, card)) < 0) {
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: mixer attach %s error: %s\n", 
	       card, snd_strerror(err));
	snd_mixer_close(handle);
	return CONTROL_ERROR;
      }

      if ((err = snd_mixer_selem_register(handle, NULL, NULL)) < 0) {
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: mixer register error: %s\n", snd_strerror(err));
	snd_mixer_close(handle);
	return CONTROL_ERROR;
      }
      err = snd_mixer_load(handle);
      if (err < 0) {
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: mixer load error: %s\n", snd_strerror(err));
	snd_mixer_close(handle);
	return CONTROL_ERROR;
      }

      elem = snd_mixer_find_selem(handle, sid);
      if (!elem) {
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: unable to find simple control '%s',%i\n",
	       snd_mixer_selem_id_get_name(sid), snd_mixer_selem_id_get_index(sid));
	snd_mixer_close(handle);
	return CONTROL_ERROR;
	}

      snd_mixer_selem_get_playback_volume_range(elem,&pmin,&pmax);
      f_multi = (100 / (float)(pmax - pmin));

      if (cmd == AOCONTROL_SET_VOLUME) {

	set_vol = vol->left / f_multi + pmin + 0.5;

	//setting channels
	if ((err = snd_mixer_selem_set_playback_volume(elem, 0, set_vol)) < 0) {
	  mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: error setting left channel, %s\n", 
		 snd_strerror(err));
	  return CONTROL_ERROR;
	}
	mp_msg(MSGT_AO,MSGL_DBG2,"left=%li, ", set_vol);

	set_vol = vol->right / f_multi + pmin + 0.5;

	if ((err = snd_mixer_selem_set_playback_volume(elem, 1, set_vol)) < 0) {
	  mp_msg(MSGT_AO,MSGL_ERR,"alsa-control: error setting right channel, %s\n", 
		 snd_strerror(err));
	  return CONTROL_ERROR;
	}
	mp_msg(MSGT_AO,MSGL_DBG2,"right=%li, pmin=%li, pmax=%li, mult=%f\n", 
	       set_vol, pmin, pmax, f_multi);
      }
      else {
	snd_mixer_selem_get_playback_volume(elem, 0, &get_vol);
	vol->left = (get_vol - pmin) * f_multi;
	snd_mixer_selem_get_playback_volume(elem, 1, &get_vol);
	vol->right = (get_vol - pmin) * f_multi;

	mp_msg(MSGT_AO,MSGL_DBG2,"left=%f, right=%f\n",vol->left,vol->right);
      }
      snd_mixer_close(handle);
      return CONTROL_OK;
    }
#endif
    
  } //end switch
  return(CONTROL_UNKNOWN);
}

static void parse_device (char *dest, const char *src, int len)
{
  char *tmp;
  memmove(dest, src, len);
  dest[len] = 0;
  while ((tmp = strrchr(dest, '.')))
    tmp[0] = ',';
  while ((tmp = strrchr(dest, '=')))
    tmp[0] = ':';
}

static void print_help ()
{
  mp_msg (MSGT_AO, MSGL_FATAL,
           "\n-ao alsa commandline help:\n"
           "Example: mplayer -ao alsa:mmap:device=hw=0.3\n"
           "  sets mmap-mode and first card fourth device\n"
           "\nOptions:\n"
           "  mmap\n"
           "    Set memory-mapped mode, experimental\n"
           "  noblock\n"
           "    Sets non-blocking mode\n"
           "  device=<device-name>\n"
           "    Sets device (change , to . and : to =)\n");
}

static int str_maxlen(strarg_t *str) {
  if (str->len > ALSA_DEVICE_SIZE)
    return 0;
  return 1;
}

/*
    open & setup audio device
    return: 1=success 0=fail
*/
static int init(int rate_hz, int channels, int format, int flags)
{
    int err;
    int cards = -1;
    snd_pcm_info_t *alsa_info;
    char *str_block_mode;
    int dir = 0;
    int block;
    strarg_t device;
    snd_pcm_uframes_t bufsize;
    opt_t subopts[] = {
      {"mmap", OPT_ARG_BOOL, &ao_mmap, NULL},
      {"block", OPT_ARG_BOOL, &block, NULL},
      {"device", OPT_ARG_STR, &device, (opt_test_f)str_maxlen},
      {NULL}
    };

    char alsa_device[ALSA_DEVICE_SIZE + 1];
    // make sure alsa_device is null-terminated even when using strncpy etc.
    memset(alsa_device, 0, ALSA_DEVICE_SIZE + 1);

    mp_msg(MSGT_AO,MSGL_V,"alsa-init: requested format: %d Hz, %d channels, %x\n", rate_hz,
	channels, format);
    alsa_handler = NULL;
    mp_msg(MSGT_AO,MSGL_V,"alsa-init: compiled for ALSA-%s\n", SND_LIB_VERSION_STR);
    
    if ((err = snd_card_next(&cards)) < 0 || cards < 0)
    {
      mp_msg(MSGT_AO,MSGL_ERR,"alsa-init: no soundcards found: %s\n", snd_strerror(err));
      return(0);
    }

    ao_data.samplerate = rate_hz;
    ao_data.bps = channels * rate_hz;
    ao_data.format = format;
    ao_data.channels = channels;
    ao_data.outburst = OUTBURST;

    switch (format)
      {
      case AF_FORMAT_S8:
	alsa_format = SND_PCM_FORMAT_S8;
	break;
      case AF_FORMAT_U8:
	alsa_format = SND_PCM_FORMAT_U8;
	break;
      case AF_FORMAT_U16_LE:
	alsa_format = SND_PCM_FORMAT_U16_LE;
	break;
      case AF_FORMAT_U16_BE:
	alsa_format = SND_PCM_FORMAT_U16_BE;
	break;
#ifndef WORDS_BIGENDIAN
      case AF_FORMAT_AC3:
#endif
      case AF_FORMAT_S16_LE:
	alsa_format = SND_PCM_FORMAT_S16_LE;
	break;
#ifdef WORDS_BIGENDIAN
      case AF_FORMAT_AC3:
#endif
      case AF_FORMAT_S16_BE:
	alsa_format = SND_PCM_FORMAT_S16_BE;
	break;
      case AF_FORMAT_S32_LE:
	alsa_format = SND_PCM_FORMAT_S32_LE;
	break;
      case AF_FORMAT_S32_BE:
	alsa_format = SND_PCM_FORMAT_S32_BE;
	break;
      case AF_FORMAT_FLOAT_LE:
	alsa_format = SND_PCM_FORMAT_FLOAT_LE;
	break;

      default:
	alsa_format = SND_PCM_FORMAT_MPEG; //? default should be -1
	break;
      }
    
    //setting bw according to the input-format. resolution seems to be always s16_le or
    //u16_le so 32bit is probably obsolet. 
    switch(alsa_format)
      {
      case SND_PCM_FORMAT_S8:
      case SND_PCM_FORMAT_U8:
	ao_data.bps *= 1;
	break;
      case SND_PCM_FORMAT_S16_LE:
      case SND_PCM_FORMAT_U16_LE:
      case SND_PCM_FORMAT_S16_BE:
      case SND_PCM_FORMAT_U16_BE:
	ao_data.bps *= 2;
	break;
      case SND_PCM_FORMAT_S32_LE:
      case SND_PCM_FORMAT_S32_BE:
      case SND_PCM_FORMAT_FLOAT_LE:
	ao_data.bps *= 4;
	break;
      case -1:
	mp_msg(MSGT_AO,MSGL_ERR,"alsa-init: invalid format (%s) requested - output disabled\n",af_fmt2str_short(format));
	return(0);
	break;
      default:
	ao_data.bps *= 2;
	mp_msg(MSGT_AO,MSGL_WARN,"alsa-init: couldn't convert to right format. setting bps to: %d", ao_data.bps);
      }

    //subdevice parsing
    // set defaults
    ao_mmap = 0;
    block = 1;
    /* switch for spdif
     * sets opening sequence for SPDIF
     * sets also the playback and other switches 'on the fly'
     * while opening the abstract alias for the spdif subdevice
     * 'iec958'
     */
    if (format == AF_FORMAT_AC3) {
      unsigned char s[4];

	s[0] = IEC958_AES0_NONAUDIO | 
	  IEC958_AES0_CON_EMPHASIS_NONE;
	s[1] = IEC958_AES1_CON_ORIGINAL |