oss.c

video linux conference

/*****************************************************************************
 * oss.c : OSS /dev/dsp module for vlc
 *****************************************************************************
 * Copyright (C) 2000-2002 VideoLAN
 * $Id: oss.c 10101 2005-03-02 16:47:31Z robux4 $
 *
 * Authors: Michel Kaempf <[e-mail]>
 *          Sam Hocevar <[e-mail]>
 *          Christophe Massiot <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <errno.h>                                                 /* ENOMEM */
#include <fcntl.h>                                       /* open(), O_WRONLY */
#include <sys/ioctl.h>                                            /* ioctl() */
#include <string.h>                                            /* strerror() */
#include <unistd.h>                                      /* write(), close() */
#include <stdlib.h>                            /* calloc(), malloc(), free() */

#include <vlc/vlc.h>

#ifdef HAVE_ALLOCA_H
#   include <alloca.h>
#endif

#include <vlc/aout.h>

#include "aout_internal.h"

/* SNDCTL_DSP_RESET, SNDCTL_DSP_SETFMT, SNDCTL_DSP_STEREO, SNDCTL_DSP_SPEED,
 * SNDCTL_DSP_GETOSPACE */
#ifdef HAVE_SOUNDCARD_H
#   include <soundcard.h>
#elif defined( HAVE_SYS_SOUNDCARD_H )
#   include <sys/soundcard.h>
#elif defined( HAVE_MACHINE_SOUNDCARD_H )
#   include <machine/soundcard.h>
#endif

/* Patches for ignorant OSS versions */
#ifndef AFMT_AC3
#   define AFMT_AC3     0x00000400        /* Dolby Digital AC3 */
#endif

#ifndef AFMT_S16_NE
#   ifdef WORDS_BIGENDIAN
#       define AFMT_S16_NE AFMT_S16_BE
#   else
#       define AFMT_S16_NE AFMT_S16_LE
#   endif
#endif

/*****************************************************************************
 * aout_sys_t: OSS audio output method descriptor
 *****************************************************************************
 * This structure is part of the audio output thread descriptor.
 * It describes the DSP specific properties of an audio device.
 *****************************************************************************/
struct aout_sys_t
{
    int i_fd;
    int b_workaround_buggy_driver;
    int i_fragstotal;
    mtime_t max_buffer_duration;
};

/* This must be a power of 2. */
#define FRAME_SIZE 1024
#define FRAME_COUNT 4

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Open         ( vlc_object_t * );
static void Close        ( vlc_object_t * );

static void Play         ( aout_instance_t * );
static int  OSSThread    ( aout_instance_t * );

static mtime_t BufferDuration( aout_instance_t * p_aout );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define BUGGY_TEXT N_("Try to work around buggy OSS drivers")
#define BUGGY_LONGTEXT N_( \
    "Some buggy OSS drivers just don't like when their internal buffers " \
    "are completely filled (the sound gets heavily hashed). If you have one " \
    "of these drivers, then you need to enable this option." )

vlc_module_begin();
    set_shortname( "OSS" );
    set_description( _("Linux OSS audio output") );

    set_category( CAT_AUDIO );
    set_subcategory( SUBCAT_AUDIO_AOUT );
    add_file( "dspdev", "/dev/dsp", aout_FindAndRestart,
              N_("OSS DSP device"), NULL, VLC_FALSE );
    add_bool( "oss-buggy", 0, NULL, BUGGY_TEXT, BUGGY_LONGTEXT, VLC_TRUE );

    set_capability( "audio output", 100 );
    add_shortcut( "oss" );
    set_callbacks( Open, Close );
vlc_module_end();

/*****************************************************************************
 * Probe: probe the audio device for available formats and channels
 *****************************************************************************/
static void Probe( aout_instance_t * p_aout )
{
    struct aout_sys_t * p_sys = p_aout->output.p_sys;
    vlc_value_t val, text;
    int i_format, i_nb_channels;

    var_Create( p_aout, "audio-device", VLC_VAR_INTEGER | VLC_VAR_HASCHOICE );
    text.psz_string = _("Audio Device");
    var_Change( p_aout, "audio-device", VLC_VAR_SETTEXT, &text, NULL );

    /* Test for multi-channel. */
#ifdef SNDCTL_DSP_GETCHANNELMASK
    if ( aout_FormatNbChannels( &p_aout->output.output ) > 2 )
    {
        /* Check that the device supports this. */

        int i_chanmask;

        /* Reset all. */
        i_format = AFMT_S16_NE;
        if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 ||
            ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0 )
        {
            msg_Err( p_aout, "cannot reset OSS audio device" );
            var_Destroy( p_aout, "audio-device" );
            return;
        }

        if ( ioctl( p_sys->i_fd, SNDCTL_DSP_GETCHANNELMASK,
                    &i_chanmask ) == 0 )
        {
            if ( !(i_chanmask & DSP_BIND_FRONT) )
            {
                msg_Err( p_aout, "No front channels ! (%x)",
                         i_chanmask );
                return;
            }

            if ( (i_chanmask & (DSP_BIND_SURR | DSP_BIND_CENTER_LFE))
                  && (p_aout->output.output.i_physical_channels ==
                       (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
                         | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
                         | AOUT_CHAN_LFE)) )
            {
                val.i_int = AOUT_VAR_5_1;
                text.psz_string = N_("5.1");
                var_Change( p_aout, "audio-device",
                            VLC_VAR_ADDCHOICE, &val, &text );
            }

            if ( (i_chanmask & DSP_BIND_SURR)
                  && (p_aout->output.output.i_physical_channels &
                       (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
                         | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT)) )
            {
                val.i_int = AOUT_VAR_2F2R;
                text.psz_string = N_("2 Front 2 Rear");
                var_Change( p_aout, "audio-device",
                            VLC_VAR_ADDCHOICE, &val, &text );
            }
        }
    }
#endif

    /* Reset all. */
    i_format = AFMT_S16_NE;
    if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 ||
        ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0 )
    {
        msg_Err( p_aout, "cannot reset OSS audio device" );
        var_Destroy( p_aout, "audio-device" );
        return;
    }

    /* Test for stereo. */
    i_nb_channels = 2;
    if( ioctl( p_sys->i_fd, SNDCTL_DSP_CHANNELS, &i_nb_channels ) >= 0
         && i_nb_channels == 2 )
    {
        val.i_int = AOUT_VAR_STEREO;
        text.psz_string = N_("Stereo");
        var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
    }

    /* Reset all. */
    i_format = AFMT_S16_NE;
    if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 ||
        ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0 )
    {
        msg_Err( p_aout, "cannot reset OSS audio device" );
        var_Destroy( p_aout, "audio-device" );
        return;
    }

    /* Test for mono. */
    i_nb_channels = 1;
    if( ioctl( p_sys->i_fd, SNDCTL_DSP_CHANNELS, &i_nb_channels ) >= 0
         && i_nb_channels == 1 )
    {
        val.i_int = AOUT_VAR_MONO;
        text.psz_string = N_("Mono");
        var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
        if ( p_aout->output.output.i_physical_channels == AOUT_CHAN_CENTER )
        {
            var_Set( p_aout, "audio-device", val );
        }
    }

    if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 )
    {
        msg_Err( p_aout, "cannot reset OSS audio device" );
        var_Destroy( p_aout, "audio-device" );
        return;
    }

    /* Test for spdif. */
    if ( AOUT_FMT_NON_LINEAR( &p_aout->output.output ) )
    {
        i_format = AFMT_AC3;

        if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) >= 0
             && i_format == AFMT_AC3 )
        {
            val.i_int = AOUT_VAR_SPDIF;
            text.psz_string = N_("A/52 over S/PDIF");
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            if( config_GetInt( p_aout, "spdif" ) )
                var_Set( p_aout, "audio-device", val );
        }
        else if( config_GetInt( p_aout, "spdif" ) )
        {
            msg_Warn( p_aout, "s/pdif not supported by card" );
        }
    }

    var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart,
                     NULL );
}

/*****************************************************************************
 * Open: open the audio device (the digital sound processor)
 *****************************************************************************
 * This function opens the DSP as a usual non-blocking write-only file, and
 * modifies the p_aout->p_sys->i_fd with the file's descriptor.
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    aout_instance_t * p_aout = (aout_instance_t *)p_this;
    struct aout_sys_t * p_sys;
    char * psz_device;
    vlc_value_t val;

    /* Allocate structure */
    p_aout->output.p_sys = p_sys = malloc( sizeof( aout_sys_t ) );
    if( p_sys == NULL )
    {
        msg_Err( p_aout, "out of memory" );
        return VLC_ENOMEM;
    }

    /* Get device name */
    if( (psz_device = config_GetPsz( p_aout, "dspdev" )) == NULL )
    {
        msg_Err( p_aout, "no audio device specified (maybe /dev/dsp?)" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    /* Open the sound device in non-blocking mode, because ALSA's OSS
     * emulation and some broken OSS drivers would make a blocking call
     * wait forever until the device is available. Since this breaks the
     * OSS spec, we immediately put it back to blocking mode if the
     * operation was successful. */
    p_sys->i_fd = open( psz_device, O_WRONLY | O_NDELAY );
    if( p_sys->i_fd < 0 )
    {
        msg_Err( p_aout, "cannot open audio device (%s)", psz_device );
        free( p_sys );
        return VLC_EGENERIC;
    }

    /* if the opening was ok, put the device back in blocking mode */
    fcntl( p_sys->i_fd, F_SETFL,
            fcntl( p_sys->i_fd, F_GETFL ) &~ FNDELAY );

    free( psz_device );

    p_aout->output.pf_play = Play;

    if ( var_Type( p_aout, "audio-device" ) == 0 )
    {
        Probe( p_aout );
    }

    if ( var_Get( p_aout, "audio-device", &val ) < 0 )
    {
        /* Probe() has failed. */
        free( p_sys );
        return VLC_EGENERIC;
    }

    if ( val.i_int == AOUT_VAR_SPDIF )
    {
        p_aout->output.output.i_format = VLC_FOURCC('s','p','d','i');
    }
    else if ( val.i_int == AOUT_VAR_5_1 )
    {
        p_aout->output.output.i_format = AOUT_FMT_S16_NE;
        p_aout->output.output.i_physical_channels
            = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
               | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
               | AOUT_CHAN_LFE;
    }
    else if ( val.i_int == AOUT_VAR_2F2R )
    {
        p_aout->output.output.i_format = AOUT_FMT_S16_NE;
        p_aout->output.output.i_physical_channels
            = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
               | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
    }
    else if ( val.i_int == AOUT_VAR_STEREO )
    {