text: /*****************************************************************************
   * oss.c : OSS input module for vlc
   *****************************************************************************
   * Copyright (C) 2002-2009 VLC authors and VideoLAN
   * $Id: d50a23cdb030354acd30a7329fc08a462006431b $
   *
   * Authors: Benjamin Pracht <bigben at videolan dot org>
   *          Richard Hosking <richard at hovis dot net>
   *          Antoine Cellerier <dionoea at videolan d.t org>
   *          Dennis Lou <dlou99 at yahoo dot com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This program 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 Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with this program; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
   *****************************************************************************/
  
  /*****************************************************************************
   * Preamble
   *****************************************************************************/
  
  #ifdef HAVE_CONFIG_H
  # include "config.h"
  #endif
  
  #include <vlc_common.h>
  #include <vlc_plugin.h>
  #include <vlc_access.h>
  #include <vlc_demux.h>
  #include <vlc_fs.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <sys/ioctl.h>
  #include <sys/mman.h>
  
  #ifdef HAVE_SYS_SOUNDCARD_H
  #  include <sys/soundcard.h>
  #endif
  #ifdef HAVE_SOUNDCARD_H
  #  include <soundcard.h>
  #endif
  
  #include <poll.h>
  
  /*****************************************************************************
   * Module descriptior
   *****************************************************************************/
  
  static int  DemuxOpen ( vlc_object_t * );
  static void DemuxClose( vlc_object_t * );
  
  
  #define STEREO_TEXT N_( "Stereo" )
  #define STEREO_LONGTEXT N_( \
      "Capture the audio stream in stereo." )
  #define SAMPLERATE_TEXT N_( "Samplerate" )
  #define SAMPLERATE_LONGTEXT N_( \
      "Samplerate of the captured audio stream, in Hz (eg: 11025, 22050, 44100, 48000)" )
  
  #define OSS_DEFAULT "/dev/dsp"
  
  #define CFG_PREFIX "oss-"
  
  vlc_module_begin ()
      set_shortname( N_("OSS") )
      set_description( N_("OSS input") )
      set_category( CAT_INPUT )
      set_subcategory( SUBCAT_INPUT_ACCESS )
  
      add_shortcut( "oss" )
      set_capability( "access_demux", 10 )
      set_callbacks( DemuxOpen, DemuxClose )
  
      add_bool( CFG_PREFIX "stereo", true, STEREO_TEXT, STEREO_LONGTEXT,
                  true )
      add_integer( CFG_PREFIX "samplerate", 48000, SAMPLERATE_TEXT,
                  SAMPLERATE_LONGTEXT, true )
  vlc_module_end ()
  
  /*****************************************************************************
   * Access: local prototypes
   *****************************************************************************/
  
  static int DemuxControl( demux_t *, int, va_list );
  
  static int Demux( demux_t * );
  
  static block_t* GrabAudio( demux_t *p_demux );
  
  static int OpenAudioDev( demux_t * );
  static int OpenAudioDevOss( demux_t * );
  static bool ProbeAudioDevOss( demux_t *, const char *psz_device );
  
  struct buffer_t
  {
      void *  start;
      size_t  length;
  };
  
  struct demux_sys_t
  {
      const char *psz_device;  /* OSS device from MRL */
  
      int  i_fd;
  
      /* Audio */
      unsigned int i_sample_rate;
      bool b_stereo;
      size_t i_max_frame_size;
      block_t *p_block;
      es_out_id_t *p_es;
  
      int64_t i_next_demux_date; /* Used to handle oss:// as input-slave properly */
  };
  
  static int FindMainDevice( demux_t *p_demux )
  {
      msg_Dbg( p_demux, "opening device '%s'", p_demux->p_sys->psz_device );
      if( ProbeAudioDevOss( p_demux, p_demux->p_sys->psz_device ) )
      {
          msg_Dbg( p_demux, "'%s' is an audio device", p_demux->p_sys->psz_device );
          p_demux->p_sys->i_fd = OpenAudioDev( p_demux );
      }
  
      if( p_demux->p_sys->i_fd < 0 )
          return VLC_EGENERIC;
      return VLC_SUCCESS;
  }
  
  /*****************************************************************************
   * DemuxOpen: opens oss device, access_demux callback
   *****************************************************************************
   *
   * url: <oss device>::::
   *
   *****************************************************************************/
  static int DemuxOpen( vlc_object_t *p_this )
  {
      demux_t     *p_demux = (demux_t*)p_this;
      demux_sys_t *p_sys;
  
      /* Only when selected */
      if( *p_demux->psz_access == '\0' ) return VLC_EGENERIC;
  
      /* Set up p_demux */
      p_demux->pf_control = DemuxControl;
      p_demux->pf_demux = Demux;
      p_demux->info.i_update = 0;
      p_demux->info.i_title = 0;
      p_demux->info.i_seekpoint = 0;
  
      p_demux->p_sys = p_sys = vlc_obj_calloc( p_this, 1, sizeof( demux_sys_t ) );
      if( p_sys == NULL ) return VLC_ENOMEM;
  
      p_sys->i_sample_rate = var_InheritInteger( p_demux, CFG_PREFIX "samplerate" );
      p_sys->b_stereo = var_InheritBool( p_demux, CFG_PREFIX "stereo" );
      p_sys->i_fd = -1;
      p_sys->p_es = NULL;
      p_sys->p_block = NULL;
      p_sys->i_next_demux_date = -1;
  
      if( p_demux->psz_location && *p_demux->psz_location )
          p_sys->psz_device = p_demux->psz_location;
      else
          p_sys->psz_device = OSS_DEFAULT;
  
      if( FindMainDevice( p_demux ) != VLC_SUCCESS )
      {
          DemuxClose( p_this );
          return VLC_EGENERIC;
      }
  
      return VLC_SUCCESS;
  }
  
  /*****************************************************************************
   * Close: close device, free resources
   *****************************************************************************/
  static void DemuxClose( vlc_object_t *p_this )
  {
      demux_t     *p_demux = (demux_t *)p_this;
      demux_sys_t *p_sys   = p_demux->p_sys;
  
      if( p_sys->i_fd >= 0 )
          vlc_close( p_sys->i_fd );
  
      if( p_sys->p_block ) block_Release( p_sys->p_block );
  }
  
  /*****************************************************************************
   * DemuxControl:
   *****************************************************************************/
  static int DemuxControl( demux_t *p_demux, int i_query, va_list args )
  {
      demux_sys_t *p_sys = p_demux->p_sys;
      bool *pb;
      int64_t    *pi64;
  
      switch( i_query )
      {
          /* Special for access_demux */
          case DEMUX_CAN_PAUSE:
          case DEMUX_CAN_SEEK:
          case DEMUX_CAN_CONTROL_PACE:
              pb = va_arg( args, bool * );
              *pb = false;
              return VLC_SUCCESS;
  
          case DEMUX_GET_PTS_DELAY:
              pi64 = va_arg( args, int64_t * );
              *pi64 = INT64_C(1000)
                    * var_InheritInteger( p_demux, "live-caching" );
              return VLC_SUCCESS;
  
          case DEMUX_GET_TIME:
              pi64 = va_arg( args, int64_t * );
              *pi64 = mdate();
              return VLC_SUCCESS;
  
          case DEMUX_SET_NEXT_DEMUX_TIME:
              p_sys->i_next_demux_date = va_arg( args, int64_t );
              return VLC_SUCCESS;
  
          /* TODO implement others */
          default:
              return VLC_EGENERIC;
      }
  
      return VLC_EGENERIC;
  }
  
  /*****************************************************************************
   * Demux: Processes the audio frame
   *****************************************************************************/
  static int Demux( demux_t *p_demux )
  {
      demux_sys_t *p_sys = p_demux->p_sys;
  
      struct pollfd fd;
      fd.fd = p_sys->i_fd;
      fd.events = POLLIN|POLLPRI;
      fd.revents = 0;
  
      block_t *p_block = NULL;
  
      do
      {
          if( p_block )
          {
              es_out_Send( p_demux->out, p_sys->p_es, p_block );
              p_block = NULL;
          }
  
          /* Wait for data */
          if( poll( &fd, 1, 10 ) ) /* Timeout after 0.01 seconds. Bigger delays are an issue when used with/as an input-slave since all the inputs run in the same thread. */
          {
              if( errno == EINTR )
                  continue;
              if( fd.revents & (POLLIN|POLLPRI) )
              {
                  p_block = GrabAudio( p_demux );
                  if( p_block )
                      es_out_SetPCR( p_demux->out, p_block->i_pts );
              }
          }
      } while( p_block && p_sys->i_next_demux_date > 0 &&
               p_block->i_pts < p_sys->i_next_demux_date );
  
      if( p_block )
          es_out_Send( p_demux->out, p_sys->p_es, p_block );
  
      return 1;
  }
  
  /*****************************************************************************
   * GrabAudio: Grab an audio frame
   *****************************************************************************/
  static block_t* GrabAudio( demux_t *p_demux )
  {
      demux_sys_t *p_sys = p_demux->p_sys;
      struct audio_buf_info buf_info;
      int i_read = 0, i_correct;
      block_t *p_block;
  
      if( p_sys->p_block ) p_block = p_sys->p_block;
      else p_block = block_Alloc( p_sys->i_max_frame_size );
  
      if( !p_block )
      {
          msg_Warn( p_demux, "cannot get block" );
          return NULL;
      }
  
      p_sys->p_block = p_block;
  
      i_read = read( p_sys->i_fd, p_block->p_buffer,
                  p_sys->i_max_frame_size );
  
      if( i_read <= 0 ) return NULL;
  
      p_block->i_buffer = i_read;
      p_sys->p_block = NULL;
  
      /* Correct the date because of kernel buffering */
      i_correct = i_read;
      if( ioctl( p_sys->i_fd, SNDCTL_DSP_GETISPACE, &buf_info ) == 0 )
      {
          i_correct += buf_info.bytes;
      }
  
      /* Timestamp */
      p_block->i_pts = p_block->i_dts =
          mdate() - INT64_C(1000000) * (mtime_t)i_correct /
          2 / ( p_sys->b_stereo ? 2 : 1) / p_sys->i_sample_rate;
  
      return p_block;
  }
  
  /*****************************************************************************
   * OpenAudioDev: open and set up the audio device and probe for capabilities
   *****************************************************************************/
  static int OpenAudioDevOss( demux_t *p_demux )
  {
      int i_fd;
      int i_format;
  
      i_fd = vlc_open( p_demux->p_sys->psz_device, O_RDONLY | O_NONBLOCK );
  
      if( i_fd < 0 )
      {
          msg_Err( p_demux, "cannot open OSS audio device (%s)",
                   vlc_strerror_c(errno) );
          goto adev_fail;
      }
  
      i_format = AFMT_S16_LE;
      if( ioctl( i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0
          || i_format != AFMT_S16_LE )
      {
          msg_Err( p_demux,
                   "cannot set audio format (16b little endian) (%s)",
                   vlc_strerror_c(errno) );
          goto adev_fail;
      }
  
      if( ioctl( i_fd, SNDCTL_DSP_STEREO,
                 &p_demux->p_sys->b_stereo ) < 0 )
      {
          msg_Err( p_demux, "cannot set audio channels count (%s)",
                   vlc_strerror_c(errno) );
          goto adev_fail;
      }
  
      if( ioctl( i_fd, SNDCTL_DSP_SPEED,
                 &p_demux->p_sys->i_sample_rate ) < 0 )
      {
          msg_Err( p_demux, "cannot set audio sample rate (%s)",
                   vlc_strerror_c(errno) );
          goto adev_fail;
      }
  
      p_demux->p_sys->i_max_frame_size = 6 * 1024;
  
      return i_fd;
  
   adev_fail:
  
      if( i_fd >= 0 )
          vlc_close( i_fd );
      return -1;
  }
  
  static int OpenAudioDev( demux_t *p_demux )
  {
      demux_sys_t *p_sys = p_demux->p_sys;
      int i_fd = OpenAudioDevOss( p_demux );
  
      if( i_fd < 0 )
          return i_fd;
  
      msg_Dbg( p_demux, "opened adev=`%s' %s %dHz",
               p_sys->psz_device, p_sys->b_stereo ? "stereo" : "mono",
               p_sys->i_sample_rate );
  
      es_format_t fmt;
      es_format_Init( &fmt, AUDIO_ES, VLC_CODEC_S16L );
  
      fmt.audio.i_channels = p_sys->b_stereo ? 2 : 1;
      fmt.audio.i_rate = p_sys->i_sample_rate;
      fmt.audio.i_bitspersample = 16;
      fmt.audio.i_blockalign = fmt.audio.i_channels * fmt.audio.i_bitspersample / 8;
      fmt.i_bitrate = fmt.audio.i_channels * fmt.audio.i_rate * fmt.audio.i_bitspersample;
  
      msg_Dbg( p_demux, "new audio es %d channels %dHz",
               fmt.audio.i_channels, fmt.audio.i_rate );
  
      p_sys->p_es = es_out_Add( p_demux->out, &fmt );
  
      return i_fd;
  }
  
  /*****************************************************************************
   * ProbeAudioDev: probe audio for capabilities
   *****************************************************************************/
  static bool ProbeAudioDevOss( demux_t *p_demux, const char *psz_device )
  {
      int i_caps;
      int i_fd = vlc_open( psz_device, O_RDONLY | O_NONBLOCK );
  
      if( i_fd < 0 )
      {
          msg_Err( p_demux, "cannot open device %s for OSS audio (%s)",
                   psz_device, vlc_strerror_c(errno) );
          goto open_failed;
      }
  
      /* this will fail if the device is video */
      if( ioctl( i_fd, SNDCTL_DSP_GETCAPS, &i_caps ) < 0 )
      {
          msg_Err( p_demux, "cannot get audio caps (%s)",
                   vlc_strerror_c(errno) );
          goto open_failed;
      }
  
      if( i_fd >= 0 )
          vlc_close( i_fd );
  
      return true;
  
  open_failed:
      if( i_fd >= 0 )
          vlc_close( i_fd );
      return false;
  }
  