5.1 surround sound in VLC with OSS4

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5.1 surround sound in VLC with OSS4

Postby saa » Sun Apr 17, 2011 6:39 am

I found switching to OSS4 works great with superb sound quality. But VLC 1.1.9 has only Mono and Stereo sound outputs, and no 5.1 surround sound output options when playing DVD wit 5.1 surround sound.

I get 5.1 sound using mplayer, so OSS4 is not the issue. But I would like to get 5.1 surround in VLC as DVDs and music play best in VLC.
Is there anything extra I have to do to get 5.1 surround in VLC with OSS4 (tweaking oss.c file in modules/audio_output folder). Any suggessions will be appreciated.
I am pasting below the contents of oss.c code and the output of ossinfo, osstest for information.


oss.c

/*****************************************************************************
* oss.c : OSS /dev/dsp module for vlc
*****************************************************************************
* Copyright (C) 2000-2002 the VideoLAN team
* $Id: 14d91ca1c0efa9a3d196006d4bea70f2742708fe $
*
* Authors: Michel Kaempf <maxx@via.ecp.fr>
* Sam Hocevar <sam@zoy.org>
* Christophe Massiot <massiot@via.ecp.fr>
*
* 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/

/*****************************************************************************
* Preamble
*****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <fcntl.h> /* open(), O_WRONLY */
#include <sys/ioctl.h> /* ioctl() */
#include <unistd.h> /* write(), close() */

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_fs.h>

#include <vlc_aout.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>
#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 32

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

static void Play ( aout_instance_t * );
static void* OSSThread ( vlc_object_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( N_("UNIX OSS audio output") )

set_category( CAT_AUDIO )
set_subcategory( SUBCAT_AUDIO_AOUT )
add_file( "oss-audio-device", "/dev/dsp", aout_FindAndRestart,
N_("OSS DSP device"), NULL, false )
add_deprecated_alias( "dspdev" ) /* deprecated since 0.9.3 */
add_bool( "oss-buggy", false, NULL, BUGGY_TEXT, BUGGY_LONGTEXT, 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 = (char*) "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 = _("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 = _("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 = _("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 = _("A/52 over S/PDIF");
var_Change( p_aout, "audio-device",
VLC_VAR_ADDCHOICE, &val, &text );
if( var_InheritBool( p_aout, "spdif" ) )
var_Set( p_aout, "audio-device", val );
}
else if( var_InheritBool( 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 )
return VLC_ENOMEM;

/* Get device name */
if( (psz_device = var_InheritString( p_aout, "oss-audio-device" )) == 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 = vlc_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( 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. */
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

if ( val.i_int == AOUT_VAR_SPDIF )
{
p_aout->output.output.i_format = VLC_CODEC_SPDIFL;
}
else if ( val.i_int == AOUT_VAR_5_1 )
{
p_aout->output.output.i_format = VLC_CODEC_S16N;
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 = VLC_CODEC_S16N;
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 )
{
p_aout->output.output.i_format = VLC_CODEC_S16N;
p_aout->output.output.i_physical_channels
= AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
}
else if ( val.i_int == AOUT_VAR_MONO )
{
p_aout->output.output.i_format = VLC_CODEC_S16N;
p_aout->output.output.i_physical_channels = AOUT_CHAN_CENTER;
}
else
{
/* This should not happen ! */
msg_Err( p_aout, "internal: can't find audio-device (%i)", val.i_int );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

var_SetBool( p_aout, "intf-change", true );

/* Reset the DSP device */
if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 )
{
msg_Err( p_aout, "cannot reset OSS audio device" );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

/* Set the output format */
if ( AOUT_FMT_NON_LINEAR( &p_aout->output.output ) )
{
int i_format = AFMT_AC3;

if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0
|| i_format != AFMT_AC3 )
{
msg_Err( p_aout, "cannot reset OSS audio device" );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

p_aout->output.output.i_format = VLC_CODEC_SPDIFL;
p_aout->output.i_nb_samples = A52_FRAME_NB;
p_aout->output.output.i_bytes_per_frame = AOUT_SPDIF_SIZE;
p_aout->output.output.i_frame_length = A52_FRAME_NB;

aout_VolumeNoneInit( p_aout );
}

if ( !AOUT_FMT_NON_LINEAR( &p_aout->output.output ) )
{
unsigned int i_format = AFMT_S16_NE;
unsigned int i_frame_size, i_fragments;
unsigned int i_rate;
unsigned int i_nb_channels;
audio_buf_info audio_buf;

if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0 )
{
msg_Err( p_aout, "cannot set audio output format" );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

switch ( i_format )
{
case AFMT_U8:
p_aout->output.output.i_format = VLC_CODEC_U8;
break;
case AFMT_S8:
p_aout->output.output.i_format = VLC_CODEC_S8;
break;
case AFMT_U16_LE:
p_aout->output.output.i_format = VLC_CODEC_U16L;
break;
case AFMT_S16_LE:
p_aout->output.output.i_format = VLC_CODEC_S16L;
break;
case AFMT_U16_BE:
p_aout->output.output.i_format = VLC_CODEC_U16B;
break;
case AFMT_S16_BE:
p_aout->output.output.i_format = VLC_CODEC_S16B;
break;
default:
msg_Err( p_aout, "OSS fell back to an unknown format (%d)",
i_format );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

i_nb_channels = aout_FormatNbChannels( &p_aout->output.output );

/* Set the number of channels */
if( ioctl( p_sys->i_fd, SNDCTL_DSP_CHANNELS, &i_nb_channels ) < 0 ||
i_nb_channels != aout_FormatNbChannels( &p_aout->output.output ) )
{
msg_Err( p_aout, "cannot set number of audio channels (%s)",
aout_FormatPrintChannels( &p_aout->output.output) );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

/* Set the output rate */
i_rate = p_aout->output.output.i_rate;
if( ioctl( p_sys->i_fd, SNDCTL_DSP_SPEED, &i_rate ) < 0 )
{
msg_Err( p_aout, "cannot set audio output rate (%i)",
p_aout->output.output.i_rate );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}

if( i_rate != p_aout->output.output.i_rate )
{
p_aout->output.output.i_rate = i_rate;
}

/* Set the fragment size */
aout_FormatPrepare( &p_aout->output.output );

/* i_fragment = xxxxyyyy where: xxxx is fragtotal
* 1 << yyyy is fragsize */
i_frame_size = ((uint64_t)p_aout->output.output.i_bytes_per_frame * p_aout->output.output.i_rate * 65536) / (48000 * 2 * 2) / FRAME_COUNT;
i_fragments = 4;
while( i_fragments < 12 && (1U << i_fragments) < i_frame_size )
{
++i_fragments;
}
i_fragments |= FRAME_COUNT << 16;
if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFRAGMENT, &i_fragments ) < 0 )
{
msg_Warn( p_aout, "cannot set fragment size (%.8x)", i_fragments );
}

if( ioctl( p_sys->i_fd, SNDCTL_DSP_GETOSPACE, &audio_buf ) < 0 )
{
msg_Err( p_aout, "cannot get fragment size" );
close( p_sys->i_fd );
free( p_sys );
return VLC_EGENERIC;
}
else
{
/* Number of fragments actually allocated */
p_aout->output.p_sys->i_fragstotal = audio_buf.fragstotal;

/* Maximum duration the soundcard's buffer can hold */
p_aout->output.p_sys->max_buffer_duration =
(mtime_t)audio_buf.fragstotal * audio_buf.fragsize * 1000000
/ p_aout->output.output.i_bytes_per_frame
/ p_aout->output.output.i_rate
* p_aout->output.output.i_frame_length;

p_aout->output.i_nb_samples = audio_buf.fragsize /
p_aout->output.output.i_bytes_per_frame;
}

aout_VolumeSoftInit( p_aout );
}

p_aout->output.p_sys->b_workaround_buggy_driver =
var_InheritBool( p_aout, "oss-buggy" );

/* Create OSS thread and wait for its readiness. */
if( vlc_thread_create( p_aout, "aout", OSSThread,
VLC_THREAD_PRIORITY_OUTPUT ) )
{
msg_Err( p_aout, "cannot create OSS thread (%m)" );
close( p_sys->i_fd );
free( p_sys );
return VLC_ENOMEM;
}

return VLC_SUCCESS;
}

/*****************************************************************************
* Play: nothing to do
*****************************************************************************/
static void Play( aout_instance_t *p_aout )
{
VLC_UNUSED(p_aout);
}

/*****************************************************************************
* Close: close the DSP audio device
*****************************************************************************/
static void Close( vlc_object_t * p_this )
{
aout_instance_t *p_aout = (aout_instance_t *)p_this;
struct aout_sys_t * p_sys = p_aout->output.p_sys;

vlc_object_kill( p_aout );
vlc_thread_join( p_aout );
p_aout->b_die = false;

ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL );
close( p_sys->i_fd );

free( p_sys );
}

/*****************************************************************************
* BufferDuration: buffer status query
*****************************************************************************
* This function returns the duration in microseconds of the current buffer.
*****************************************************************************/
static mtime_t BufferDuration( aout_instance_t * p_aout )
{
struct aout_sys_t * p_sys = p_aout->output.p_sys;
audio_buf_info audio_buf;
int i_bytes;

/* Fill the audio_buf_info structure:
* - fragstotal: total number of fragments allocated
* - fragsize: size of a fragment in bytes
* - bytes: available space in bytes (includes partially used fragments)
* Note! 'bytes' could be more than fragments*fragsize */
ioctl( p_sys->i_fd, SNDCTL_DSP_GETOSPACE, &audio_buf );

/* calculate number of available fragments (not partially used ones) */
i_bytes = (audio_buf.fragstotal * audio_buf.fragsize) - audio_buf.bytes;

/* Return the fragment duration */
return (mtime_t)i_bytes * 1000000
/ p_aout->output.output.i_bytes_per_frame
/ p_aout->output.output.i_rate
* p_aout->output.output.i_frame_length;
}

/*****************************************************************************
* OSSThread: asynchronous thread used to DMA the data to the device
*****************************************************************************/
static void* OSSThread( vlc_object_t *p_this )
{
aout_instance_t * p_aout = (aout_instance_t*)p_this;
struct aout_sys_t * p_sys = p_aout->output.p_sys;
mtime_t next_date = 0;
int canc = vlc_savecancel ();

while ( vlc_object_alive (p_aout) )
{
aout_buffer_t * p_buffer = NULL;
int i_tmp, i_size;
uint8_t * p_bytes;

if ( p_aout->output.output.i_format != VLC_CODEC_SPDIFL )
{
mtime_t buffered = BufferDuration( p_aout );

if( p_aout->output.p_sys->b_workaround_buggy_driver )
{
#define i_fragstotal p_aout->output.p_sys->i_fragstotal
/* Wait a bit - we don't want our buffer to be full */
if( buffered > (p_aout->output.p_sys->max_buffer_duration
/ i_fragstotal * (i_fragstotal - 1)) )
{
msleep((p_aout->output.p_sys->max_buffer_duration
/ i_fragstotal ));
buffered = BufferDuration( p_aout );
}
#undef i_fragstotal
}

/* Next buffer will be played at mdate() + buffered */
p_buffer = aout_OutputNextBuffer( p_aout, mdate() + buffered,
false );

if( p_buffer == NULL &&
buffered > ( p_aout->output.p_sys->max_buffer_duration
/ p_aout->output.p_sys->i_fragstotal ) )
{
/* If we have at least a fragment full, then we can wait a
* little and retry to get a new audio buffer instead of
* playing a blank sample */
msleep( ( p_aout->output.p_sys->max_buffer_duration
/ p_aout->output.p_sys->i_fragstotal / 2 ) );
continue;
}
}
else
{
/* emu10k1 driver does not report Buffer Duration correctly in
* passthrough mode so we have to cheat */
if( !next_date )
{
next_date = mdate();
}
else
{
mtime_t delay = next_date - mdate();
if( delay > AOUT_PTS_TOLERANCE )
{
msleep( delay / 2 );
}
}

while( vlc_object_alive (p_aout) && ! ( p_buffer =
aout_OutputNextBuffer( p_aout, next_date, true ) ) )
{
msleep( VLC_HARD_MIN_SLEEP );
next_date = mdate();
}
}

if ( p_buffer != NULL )
{
p_bytes = p_buffer->p_buffer;
i_size = p_buffer->i_buffer;
/* This is theoretical ... we'll see next iteration whether
* we're drifting */
next_date += p_buffer->i_length;
}
else
{
i_size = FRAME_SIZE / p_aout->output.output.i_frame_length
* p_aout->output.output.i_bytes_per_frame;
p_bytes = malloc( i_size );
memset( p_bytes, 0, i_size );
next_date = 0;
}

i_tmp = write( p_sys->i_fd, p_bytes, i_size );

if( i_tmp < 0 )
{
msg_Err( p_aout, "write failed (%m)" );
}

if ( p_buffer != NULL )
{
aout_BufferFree( p_buffer );
}
else
{
free( p_bytes );
}
}

vlc_restorecancel (canc);
return NULL;
}

ossinfo

Version info: OSS 4.2 (b 2004/201104131401) (0x00040100) GPL

Number of audio devices: 10
Number of audio engines: 14
Number of MIDI devices: 0
Number of mixer devices: 1

Device objects
0: osscore0 OSS core services
1: oss_hdaudio0 Intel HD Audio interrupts=9153819 (9153819)
HD Audio controller Intel HD Audio
Vendor ID 0x80863a3e
Subvendor ID 0x80865001
Codec 2: Unknown (0x111d7676/0x80865001)
2: oss_usb0 USB audio core services

MIDI devices (/dev/midi*)

Mixer devices
0: High Definition Audio 0x111d767 (Mixer 0 of device object 1)

Audio devices
HD Audio play pcm1 /dev/oss/oss_hdaudio0/pcm0 (device index 0)
HD Audio play pcm2 /dev/oss/oss_hdaudio0/pcm1 (device index 1)
HD Audio play pcm3 /dev/oss/oss_hdaudio0/pcm2 (device index 2)
HD Audio play pcm4 /dev/oss/oss_hdaudio0/pcm3 (device index 3)
HD Audio play pcm5 /dev/oss/oss_hdaudio0/pcm4 (device index 4)
HD Audio play spdifout2 /dev/oss/oss_hdaudio0/spdout0 (device index 5)
HD Audio play spdifout3 /dev/oss/oss_hdaudio0/spdout1 (device index 6)
HD Audio rec select2 /dev/oss/oss_hdaudio0/pcmin0 (device index 7)
HD Audio rec select3 /dev/oss/oss_hdaudio0/pcmin1 (device index 8)
HD Audio rec internal6 /dev/oss/oss_hdaudio0/spdin0 (device index 9)

Nodes
/dev/dsp -> /dev/oss/oss_hdaudio0/pcm0
/dev/dsp_in -> /dev/oss/oss_hdaudio0/pcm0
/dev/dsp_out -> /dev/oss/oss_hdaudio0/pcm0
/dev/dsp_ac3 -> /dev/oss/oss_hdaudio0/spdout0
/dev/dsp_mmap -> /dev/oss/oss_hdaudio0/pcm0
/dev/dsp_multich -> /dev/oss/oss_hdaudio0/pcm0

osstest

Sound subsystem and version: OSS 4.2 (b 2004/201104131401) (0x00040100)

*** Scanning sound adapter #-1 ***
/dev/oss/oss_hdaudio0/pcm0 (audio engine 0): HD Audio play pcm1
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47990.00 Hz (-0.02%)>
/dev/oss/oss_hdaudio0/pcm1 (audio engine 1): HD Audio play pcm2
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/pcm2 (audio engine 2): HD Audio play pcm3
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/pcm3 (audio engine 3): HD Audio play pcm4
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/pcm4 (audio engine 4): HD Audio play pcm5
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/spdout0 (audio engine 5): HD Audio play spdifout2
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/spdout1 (audio engine 6): HD Audio play spdifout3
- Performing audio playback test...
<left> OK <right> OK <stereo> OK <measured srate 47993.00 Hz (-0.01%)>
/dev/oss/oss_hdaudio0/pcmin0 (audio engine 7): HD Audio rec select2
- Skipping input only device
/dev/oss/oss_hdaudio0/pcmin1 (audio engine 8): HD Audio rec select3
- Skipping input only device
/dev/oss/oss_hdaudio0/spdin0 (audio engine 9): HD Audio rec internal6
- Skipping input only device

*** All tests completed OK ***

I get 5.1 sound using mplayer, so OSS4 is not the issue. But I would like to get 5.1 surround in VLC as DVDs and music play best in VLC.
Is there anything extra I have to do to get 5.1 surround in VLC with OSS4 (tweaking oss.c file in modules folder). Any help will be appreciated.
saa
New Member
 
Posts: 2
Joined: Sun Apr 17, 2011 6:22 am

Re: 5.1 surround sound in VLC with OSS4

Postby cesium » Mon Apr 18, 2011 10:24 am

I'm not too familiar with vlc, but oss.c looks mostly fine...
A) Is the "#ifdef SNDCTL_DSP_GETCHANNELMASK" part compiled in? It's possible the machine vlc was compiled on was faulty and somehow the ifdef wasn't defined? Run 'strace -ff -e trace=ioctl vlc (etc.)' and try to check if it actually sends these ioctls.
B) You can try testing what SNDCTL_DSP_GETCHANNELMASK returns. e.g.

int i_mask;
int fd = open ("/dev/dsp", O_WRONLY);
ioctl (fd, SNDCTL_DSP_GETCHANNELMASK, &i_mask);

(print out result, compare to soundcard.h values etc. etc.)
cesium
Developer
 
Posts: 902
Joined: Sun Aug 12, 2007 12:51 am

Re: 5.1 surround sound in VLC with OSS4

Postby saa » Mon Apr 18, 2011 5:46 pm

Thanks for your response. As suggested, I have run the following command in terminal 'strace -ff -e trace=ioctl ./vlc' with the following partial output. I am not sure if oss.c code has been properly compiled in vlc.

[pid 8868] ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7fff5ba40b80) = -1 ENOTTY (Inappropriate ioctl for device)
[pid 8870] ioctl(1, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7fff8ede38f0) = -1 ENOTTY (Inappropriate ioctl for device)
[pid 8870] ioctl(0, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7fff8ede3890) = -1 EINVAL (Invalid argument)
[pid 8869] ioctl(0, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7fff35f5edf0) = -1 ENOTTY (Inappropriate ioctl for device)
[pid 8870] ioctl(1, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7fff8ede3630) = -1 ENOTTY (Inappropriate ioctl for device)
[pid 8901] ioctl(11, SNDCTL_DSP_RESET, 0) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SETFMT or SOUND_PCM_READ_BITS, 0x7fc3c805c9e8) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_CHANNELS or SOUND_PCM_READ_CHANNELS, 0x7fc3c805c9e4) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_RESET, 0) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SETFMT or SOUND_PCM_READ_BITS, 0x7fc3c805c9e8) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_CHANNELS or SOUND_PCM_READ_CHANNELS, 0x7fc3c805c9e4) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_RESET, 0) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SETFMT or SOUND_PCM_READ_BITS, 0x7fc3c805c9e8) = -1 EIO (Input/output error)
[pid 8901] ioctl(11, SNDCTL_DSP_RESET, 0) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SETFMT or SOUND_PCM_READ_BITS, 0x7fc3c805c9ec) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_CHANNELS or SOUND_PCM_READ_CHANNELS, 0x7fc3c805c9e8) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SPEED or SOUND_PCM_READ_RATE, 0x7fc3c805c9e4) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_SETFRAGMENT, 0x7fc3c805c9e0) = 0
[pid 8901] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fc3c805c960) = 0
[pid 9077] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fd5cc9a2e60) = 0
[pid 9077] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fd5cc9a2e60) = 0
[pid 9077] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fd5cc9a2e60) = 0
[pid 9077] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fd5cc9a2e60) = 0
[pid 9077] ioctl(11, SNDCTL_DSP_GETOSPACE, 0x7fd5cc9a2e60) = 0

You can try testing what SNDCTL_DSP_GETCHANNELMASK returns. e.g.

int i_mask;
int fd = open ("/dev/dsp", O_WRONLY);
ioctl (fd, SNDCTL_DSP_GETCHANNELMASK, &i_mask);

(print out result, compare to soundcard.h values etc. etc.)


I would appreciate more elaboration on the above for testing SNDCTL_DSP_GETCHANNELMASK. Thanks for your help.
saa
New Member
 
Posts: 2
Joined: Sun Apr 17, 2011 6:22 am


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