* alsa.c : alsa plugin for vlc
*****************************************************************************
* Copyright (C) 2000-2001 VideoLAN
- * $Id: alsa.c,v 1.13 2001/12/30 07:09:54 sam Exp $
+ * $Id: alsa.c,v 1.18 2002/06/01 12:31:58 sam Exp $
*
- * Authors: Henri Fallon <henri@videolan.org>
+ * Authors: Henri Fallon <henri@videolan.org> - Original Author
+ * Jeffrey Baker <jwbaker@acm.org> - Port to ALSA 1.0 API
*
* 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
/*****************************************************************************
* Preamble
*****************************************************************************/
-#include <stdlib.h> /* malloc(), free() */
-#include <string.h>
+#include <errno.h> /* ENOMEM */
+#include <string.h> /* strerror() */
+#include <stdlib.h> /* calloc(), malloc(), free() */
-#include <videolan/vlc.h>
+#include <vlc/vlc.h>
+#include <vlc/aout.h>
+
+#include <alsa/asoundlib.h>
/*****************************************************************************
* Capabilities defined in the other files.
*****************************************************************************/
-void _M( aout_getfunctions )( function_list_t * p_function_list );
+static void aout_getfunctions( function_list_t * p_function_list );
+static int aout_Open ( aout_thread_t * );
+static int aout_SetFormat ( aout_thread_t * );
+static void aout_HandleXrun ( aout_thread_t *);
+static int aout_GetBufInfo ( aout_thread_t *, int i_buffer_limit );
+static void aout_Play ( aout_thread_t *, byte_t *buffer, int i_size );
+static void aout_Close ( aout_thread_t * );
/*****************************************************************************
* Build configuration tree.
*****************************************************************************/
MODULE_CONFIG_START
- ADD_COMMENT( "Yeah, alsa rocks !" )
+
MODULE_CONFIG_STOP
MODULE_INIT_START
- SET_DESCRIPTION( "Alsa audio module" )
+ SET_DESCRIPTION( _("ALSA audio module") )
ADD_CAPABILITY( AOUT, 50 )
- ADD_SHORTCUT( "alsa" )
MODULE_INIT_STOP
MODULE_ACTIVATE_START
- _M( aout_getfunctions )( &p_module->p_functions->aout );
+ aout_getfunctions( &p_module->p_functions->aout );
MODULE_ACTIVATE_STOP
MODULE_DEACTIVATE_START
MODULE_DEACTIVATE_STOP
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+typedef struct alsa_device_s
+{
+ int i_num;
+} alsa_device_t;
+
+typedef struct alsa_card_s
+{
+ int i_num;
+} alsa_card_t;
+
+/* here we store plugin dependant informations */
+
+struct aout_sys_s
+{
+ snd_pcm_t * p_alsa_handle;
+ unsigned long buffer_time;
+ unsigned long period_time;
+ unsigned long chunk_size;
+ unsigned long buffer_size;
+ unsigned long rate;
+ unsigned int bytes_per_sample;
+ unsigned int samples_per_frame;
+ unsigned int bytes_per_frame;
+};
+
+/*****************************************************************************
+ * Functions exported as capabilities. They are declared as static so that
+ * we don't pollute the namespace too much.
+ *****************************************************************************/
+static void aout_getfunctions( function_list_t * p_function_list )
+{
+ p_function_list->functions.aout.pf_open = aout_Open;
+ p_function_list->functions.aout.pf_setformat = aout_SetFormat;
+ p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
+ p_function_list->functions.aout.pf_play = aout_Play;
+ p_function_list->functions.aout.pf_close = aout_Close;
+}
+
+/*****************************************************************************
+ * aout_Open : creates a handle and opens an alsa device
+ *****************************************************************************
+ * This function opens an alsa device, through the alsa API
+ *****************************************************************************/
+static int aout_Open( aout_thread_t *p_aout )
+{
+ int i_ret;
+ char psz_alsadev[128];
+
+ /* Allocate structures */
+ p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
+ if( p_aout->p_sys == NULL )
+ {
+ msg_Err( p_aout, "out of memory" );
+ return -1;
+ }
+
+ if( p_aout->i_format != AOUT_FMT_AC3 )
+ {
+ strcpy( psz_alsadev, "default" );
+ }
+ else
+ {
+ unsigned char s[4];
+ s[0] = IEC958_AES0_CON_EMPHASIS_NONE | IEC958_AES0_NONAUDIO;
+ s[1] = IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER;
+ s[2] = 0;
+ s[3] = IEC958_AES3_CON_FS_48000;
+ sprintf( psz_alsadev, "iec958:AES0=0x%x,AES1=0x%x,AES2=0x%x,AES3=0x%x",
+ s[0], s[1], s[2], s[3] );
+ }
+
+ /* Open device */
+ i_ret = snd_pcm_open( &(p_aout->p_sys->p_alsa_handle),
+ psz_alsadev, SND_PCM_STREAM_PLAYBACK, 0);
+ if( i_ret != 0 )
+ {
+ msg_Err( p_aout, "cannot open ALSA device (%s)", snd_strerror(i_ret) );
+ return -1;
+ }
+
+ return 0;
+}
+
+/*****************************************************************************
+ * aout_SetFormat : sets the alsa output format
+ *****************************************************************************
+ * This function prepares the device, sets the rate, format, the mode
+ * ( "play as soon as you have data" ), and buffer information.
+ *****************************************************************************/
+static int aout_SetFormat( aout_thread_t *p_aout )
+{
+
+ int i_rv;
+ int i_format;
+
+ snd_pcm_hw_params_t *p_hw;
+ snd_pcm_sw_params_t *p_sw;
+
+ snd_pcm_hw_params_alloca(&p_hw);
+ snd_pcm_sw_params_alloca(&p_sw);
+
+ /* default value for snd_pcm_hw_params_set_buffer_time_near() */
+ p_aout->p_sys->buffer_time = AOUT_BUFFER_DURATION;
+
+ switch (p_aout->i_format)
+ {
+ case AOUT_FMT_S16_LE:
+ i_format = SND_PCM_FORMAT_S16_LE;
+ p_aout->p_sys->bytes_per_sample = 2;
+ break;
+
+ case AOUT_FMT_AC3:
+ i_format = SND_PCM_FORMAT_S16_LE;
+ p_aout->p_sys->bytes_per_sample = 2;
+ /* buffer_time must be 500000 to avoid a system crash */
+ p_aout->p_sys->buffer_time = 500000;
+ break;
+
+ default:
+ i_format = SND_PCM_FORMAT_S16_BE;
+ p_aout->p_sys->bytes_per_sample = 2;
+ break;
+ }
+
+ p_aout->p_sys->samples_per_frame = p_aout->i_channels;
+ p_aout->p_sys->bytes_per_frame = p_aout->p_sys->samples_per_frame *
+ p_aout->p_sys->bytes_per_sample;
+
+ i_rv = snd_pcm_hw_params_any( p_aout->p_sys->p_alsa_handle, p_hw );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to retrieve initial parameters" );
+ return( -1 );
+ }
+
+ i_rv = snd_pcm_hw_params_set_access( p_aout->p_sys->p_alsa_handle, p_hw,
+ SND_PCM_ACCESS_RW_INTERLEAVED );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set interleaved stream format" );
+ return( -1 );
+ }
+
+ i_rv = snd_pcm_hw_params_set_format( p_aout->p_sys->p_alsa_handle,
+ p_hw, i_format );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set stream sample size and word order" );
+ return( -1 );
+ }
+
+ i_rv = snd_pcm_hw_params_set_channels( p_aout->p_sys->p_alsa_handle, p_hw,
+ p_aout->i_channels );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set number of output channels" );
+ return( -1 );
+ }
+
+ i_rv = snd_pcm_hw_params_set_rate_near( p_aout->p_sys->p_alsa_handle, p_hw,
+ p_aout->i_rate, 0 );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set sample rate" );
+ return( -1 );
+ }
+ p_aout->p_sys->rate = i_rv;
+
+ i_rv = snd_pcm_hw_params_set_buffer_time_near( p_aout->p_sys->p_alsa_handle,
+ p_hw,
+ p_aout->p_sys->buffer_time,
+ 0 );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set buffer time" );
+ return( -1 );
+ }
+ p_aout->p_sys->buffer_time = i_rv;
+
+ i_rv = snd_pcm_hw_params_set_period_time_near( p_aout->p_sys->p_alsa_handle,
+ p_hw, p_aout->p_sys->buffer_time / p_aout->p_sys->bytes_per_frame, 0 );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set period time" );
+ return( -1 );
+ }
+ p_aout->p_sys->period_time = i_rv;
+
+ i_rv = snd_pcm_hw_params(p_aout->p_sys->p_alsa_handle, p_hw);
+ if (i_rv < 0)
+ {
+ msg_Err( p_aout, "unable to set hardware configuration" );
+ return( -1 );
+ }
+
+ p_aout->p_sys->chunk_size = snd_pcm_hw_params_get_period_size( p_hw, 0 );
+ p_aout->p_sys->buffer_size = snd_pcm_hw_params_get_buffer_size( p_hw );
+
+ snd_pcm_sw_params_current( p_aout->p_sys->p_alsa_handle, p_sw );
+ i_rv = snd_pcm_sw_params_set_sleep_min( p_aout->p_sys->p_alsa_handle, p_sw,
+ 0 );
+
+ i_rv = snd_pcm_sw_params_set_avail_min( p_aout->p_sys->p_alsa_handle, p_sw,
+ p_aout->p_sys->chunk_size );
+
+ /* Worked with the CVS version but not with 0.9beta3
+ i_rv = snd_pcm_sw_params_set_start_threshold( p_aout->p_sys->p_alsa_handle,
+ p_sw, p_aout->p_sys->buffer_size );
+
+ i_rv = snd_pcm_sw_params_set_stop_threshold( p_aout->p_sys->p_alsa_handle,
+ p_sw, p_aout->p_sys->buffer_size);
+ */
+ i_rv = snd_pcm_sw_params( p_aout->p_sys->p_alsa_handle, p_sw );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to set software configuration" );
+ return( -1 );
+ }
+
+ return( 0 );
+}
+
+/*****************************************************************************
+ * aout_HandleXrun : reprepare the output
+ *****************************************************************************
+ * When buffer gets empty, the driver goes in "Xrun" state, where it needs
+ * to be reprepared before playing again
+ *****************************************************************************/
+static void aout_HandleXrun(aout_thread_t *p_aout)
+{
+ int i_rv;
+
+ msg_Err( p_aout, "resetting output after buffer underrun" );
+
+// i_rv = snd_pcm_reset( p_aout->p_sys->p_alsa_handle );
+ i_rv = snd_pcm_prepare( p_aout->p_sys->p_alsa_handle );
+ if( i_rv < 0 )
+ {
+ msg_Err( p_aout, "unable to recover from buffer underrun (%s)",
+ snd_strerror( i_rv ) );
+ }
+}
+
+
+/*****************************************************************************
+ * aout_BufInfo: buffer status query
+ *****************************************************************************
+ * This function returns the number of used byte in the queue.
+ * It also deals with errors : indeed if the device comes to run out
+ * of data to play, it switches to the "underrun" status. It has to
+ * be flushed and re-prepared
+ *****************************************************************************/
+static int aout_GetBufInfo( aout_thread_t *p_aout, int i_buffer_limit )
+{
+ snd_pcm_status_t *p_status;
+ int i_alsa_get_status_returns;
+
+ snd_pcm_status_alloca( &p_status );
+
+ i_alsa_get_status_returns = snd_pcm_status( p_aout->p_sys->p_alsa_handle,
+ p_status );
+
+ if( i_alsa_get_status_returns )
+ {
+ msg_Err( p_aout, "failed getting alsa buffer info (%s)",
+ snd_strerror ( i_alsa_get_status_returns ) );
+ return ( -1 );
+ }
+
+ switch( snd_pcm_status_get_state( p_status ) )
+ {
+ case SND_PCM_STATE_XRUN :
+ aout_HandleXrun( p_aout );
+ break;
+
+ case SND_PCM_STATE_OPEN:
+ case SND_PCM_STATE_PREPARED:
+ case SND_PCM_STATE_RUNNING:
+ break;
+
+ default:
+ msg_Err( p_aout, "unhandled condition %i",
+ snd_pcm_status_get_state( p_status ) );
+ break;
+ }
+
+ return( snd_pcm_status_get_avail(p_status) *
+ p_aout->p_sys->bytes_per_frame );
+}
+
+/*****************************************************************************
+ * aout_Play : plays a sample
+ *****************************************************************************
+ * Plays a sample using the snd_pcm_writei function from the alsa API
+ *****************************************************************************/
+static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
+{
+ snd_pcm_uframes_t tot_frames;
+ snd_pcm_uframes_t frames_left;
+ snd_pcm_uframes_t rv;
+
+ tot_frames = i_size / p_aout->p_sys->bytes_per_frame;
+ frames_left = tot_frames;
+
+ while( frames_left > 0 )
+ {
+ rv = snd_pcm_writei( p_aout->p_sys->p_alsa_handle, buffer +
+ (tot_frames - frames_left) *
+ p_aout->p_sys->bytes_per_frame, frames_left );
+
+ if( (signed int) rv < 0 )
+ {
+ msg_Err( p_aout, "failed writing to output (%s)",
+ snd_strerror( rv ) );
+ return;
+ }
+
+ frames_left -= rv;
+ }
+}
+
+/*****************************************************************************
+ * aout_Close : close the Alsa device
+ *****************************************************************************/
+static void aout_Close( aout_thread_t *p_aout )
+{
+ int i_close_returns;
+
+ i_close_returns = snd_pcm_close( p_aout->p_sys->p_alsa_handle );
+
+ if( i_close_returns )
+ {
+ msg_Err( p_aout, "failed closing ALSA device (%s)",
+ snd_strerror( i_close_returns ) );
+ }
+
+ free( p_aout->p_sys );
+}
+
projects / vlc / blobdiff