* oss.c : OSS /dev/dsp module for vlc
*****************************************************************************
* Copyright (C) 2000-2002 VideoLAN
- * $Id: oss.c,v 1.18 2002/08/25 09:40:00 sam Exp $
+ * $Id: oss.c,v 1.22 2002/08/31 22:10:25 stef Exp $
*
* Authors: Michel Kaempf <maxx@via.ecp.fr>
* Samuel Hocevar <sam@zoy.org>
struct aout_sys_t
{
int i_fd;
- volatile vlc_bool_t b_initialized;
};
#define FRAME_SIZE 1024
static int Open ( vlc_object_t * );
static void Close ( vlc_object_t * );
-static int SetFormat ( aout_instance_t * );
static void Play ( aout_instance_t * );
static int OSSThread ( aout_instance_t * );
aout_instance_t * p_aout = (aout_instance_t *)p_this;
struct aout_sys_t * p_sys;
char * psz_device;
+ int i_format;
+ int i_rate;
+ int i_frame_size;
+ int i_fragments;
+ vlc_bool_t b_stereo;
/* Allocate structure */
p_aout->output.p_sys = p_sys = malloc( sizeof( aout_sys_t ) );
}
free( psz_device );
- /* Create OSS thread and wait for its readiness. */
- p_sys->b_initialized = VLC_FALSE;
- if( vlc_thread_create( p_aout, "aout", OSSThread, VLC_FALSE ) )
- {
- msg_Err( p_aout, "cannot create OSS thread (%s)", strerror(errno) );
- close( p_sys->i_fd );
- free( psz_device );
- free( p_sys );
- return VLC_ETHREAD;
- }
-
- p_aout->output.pf_setformat = SetFormat;
p_aout->output.pf_play = Play;
- return VLC_SUCCESS;
-}
-
-/*****************************************************************************
- * SetFormat: reset the dsp and set its format
- *****************************************************************************
- * This functions resets the DSP device, tries to initialize the output
- * format with the value contained in the dsp structure, and if this value
- * could not be set, the default value returned by ioctl is set. It then
- * does the same for the stereo mode, and for the output rate.
- *****************************************************************************/
-static int SetFormat( aout_instance_t *p_aout )
-{
- struct aout_sys_t * p_sys = p_aout->output.p_sys;
- int i_format;
- int i_rate;
- int i_fragments;
- vlc_bool_t b_stereo;
-
- p_sys->b_initialized = VLC_FALSE;
-
/* Reset the DSP device */
if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 )
{
msg_Err( p_aout, "cannot reset OSS audio device" );
return VLC_EGENERIC;
}
-
- /* Set the fragment size */
- i_fragments = FRAME_COUNT << 16 | FRAME_SIZE;
+
+ /* Set the fragment size
+ * i_fragment = xxxxyyyy where: xxxx is fragtotal
+ * 1 << yyyy is fragsize */
+ i_fragments = 0;
+ i_frame_size = FRAME_SIZE;
+ while( i_frame_size >>= 1 )
+ {
+ ++i_fragments;
+ }
+ i_fragments |= FRAME_COUNT << 16;
if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFRAGMENT, &i_fragments ) < 0 )
{
msg_Err( p_aout, "cannot set fragment size (%.8x)", i_fragments );
}
}
- p_sys->b_initialized = VLC_TRUE;
+ /* Create OSS thread and wait for its readiness. */
+ if( vlc_thread_create( p_aout, "aout", OSSThread,
+ VLC_THREAD_PRIORITY_OUTPUT, VLC_FALSE ) )
+ {
+ msg_Err( p_aout, "cannot create OSS thread (%s)", strerror(errno) );
+ close( p_sys->i_fd );
+ free( psz_device );
+ free( p_sys );
+ return VLC_ETHREAD;
+ }
return VLC_SUCCESS;
}
/*****************************************************************************
- * Play: queue a buffer for playing by OSSThread
+ * Play: nothing to do
*****************************************************************************/
static void Play( aout_instance_t *p_aout )
{
/*****************************************************************************
- * GetBufInfo: buffer status query
+ * BufferDuration: buffer status query
*****************************************************************************
- * This function fills in the audio_buf_info structure :
- * - returns : number of available fragments (not partially used ones)
- * - int fragstotal : total number of fragments allocated
- * - int fragsize : size of a fragment in bytes
- * - int bytes : available space in bytes (includes partially used fragments)
- * Note! 'bytes' could be more than fragments*fragsize
+ * This function returns the duration in microseconds of the current buffer.
*****************************************************************************/
-static int GetBufInfo( aout_instance_t * p_aout )
+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 );
- /* returns the allocated space in bytes */
- return ( (audio_buf.fragstotal * audio_buf.fragsize) - audio_buf.bytes );
+ /* 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;
}
/*****************************************************************************
static int OSSThread( aout_instance_t * p_aout )
{
struct aout_sys_t * p_sys = p_aout->output.p_sys;
+ mtime_t next_date = 0;
while ( !p_aout->b_die )
{
int i_tmp, i_size;
byte_t * p_bytes;
- if( !p_sys->b_initialized )
- {
- msleep( THREAD_SLEEP );
- continue;
- }
-
if ( p_aout->output.output.i_format != AOUT_FMT_SPDIF )
{
- mtime_t buffered;
+ mtime_t buffered = BufferDuration( p_aout );
- do
+ /* Wait a bit - we don't want our buffer to be full */
+ while( buffered > AOUT_PTS_TOLERANCE * 2 )
{
- buffered = (mtime_t)GetBufInfo( p_aout ) * 1000000
- / p_aout->output.output.i_bytes_per_frame
- / p_aout->output.output.i_rate
- * p_aout->output.output.i_frame_length;
- if( buffered < 50000 )
- {
- break;
- }
msleep( buffered / 2 - 10000 );
+ buffered = BufferDuration( p_aout );
+ }
- } while( VLC_TRUE );
+ if( !next_date )
+ {
+ /* This is the _real_ presentation date */
+ next_date = mdate() + buffered;
+ }
+ else
+ {
+ /* Give a hint to the audio output about our drift, but
+ * not too much because we want to make it happy with our
+ * nicely calculated dates. */
+ next_date = ( (next_date * 7) + (mdate() + buffered) ) / 8;
+ }
/* Next buffer will be played at mdate()+buffered */
- p_buffer = aout_OutputNextBuffer( p_aout, mdate() + buffered,
- VLC_FALSE );
+ p_buffer = aout_OutputNextBuffer( p_aout, next_date, VLC_FALSE );
}
else
{
{
p_bytes = p_buffer->p_buffer;
i_size = p_buffer->i_nb_bytes;
+ /* This is theoretical ... we'll see next iteration whether
+ * we're drifting */
+ next_date += p_buffer->end_date - p_buffer->start_date;
}
else
{
* 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 );
projects / vlc / blobdiff