jack.c

/*****************************************************************************
 * jack.c : JACK audio output module
 *****************************************************************************
 * Copyright (C) 2006 VLC authors and VideoLAN
 * $Id$
 *
 * Authors: Cyril Deguet <asmax _at_ videolan.org>
 *          Jon Griffiths <jon_p_griffiths _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.
 *****************************************************************************/
/**
 * \file modules/audio_output/jack.c
 * \brief JACK audio output functions
 */
/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <unistd.h>                                      /* write(), close() */

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

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

#include <jack/jack.h>
#include <jack/ringbuffer.h>

typedef jack_default_audio_sample_t jack_sample_t;

/*****************************************************************************
 * aout_sys_t: JACK audio output method descriptor
 *****************************************************************************
 * This structure is part of the audio output thread descriptor.
 * It describes some JACK specific variables.
 *****************************************************************************/
struct aout_sys_t
{
    jack_ringbuffer_t *p_jack_ringbuffer;
    jack_client_t  *p_jack_client;
    jack_port_t   **p_jack_ports;
    jack_sample_t **p_jack_buffers;
    unsigned int    i_channels;
    unsigned int    i_rate;
    jack_nframes_t latency;
    float soft_gain;
    bool soft_mute;
    mtime_t paused; /**< Time when (last) paused */
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Open         ( vlc_object_t * );
static void Close        ( vlc_object_t * );
static void Play         ( audio_output_t * p_aout, block_t * p_block );
static void Pause        ( audio_output_t *aout, bool paused, mtime_t date );
static void Flush        ( audio_output_t *p_aout, bool wait );
static int  TimeGet      ( audio_output_t *, mtime_t * );
static int  Process      ( jack_nframes_t i_frames, void *p_arg );
static int  GraphChange  ( void *p_arg );

#include "audio_output/volume.h"

#define AUTO_CONNECT_OPTION "jack-auto-connect"
#define AUTO_CONNECT_TEXT N_("Automatically connect to writable clients")
#define AUTO_CONNECT_LONGTEXT N_( \
    "If enabled, this option will automatically connect sound output to the " \
    "first writable JACK clients found." )

#define CONNECT_REGEX_OPTION "jack-connect-regex"
#define CONNECT_REGEX_TEXT N_("Connect to clients matching")
#define CONNECT_REGEX_LONGTEXT N_( \
    "If automatic connection is enabled, only JACK clients whose names " \
    "match this regular expression will be considered for connection." )

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin ()
    set_shortname( "JACK" )
    set_description( N_("JACK audio output") )
    set_capability( "audio output", 100 )
    set_category( CAT_AUDIO )
    set_subcategory( SUBCAT_AUDIO_AOUT )
    add_bool( AUTO_CONNECT_OPTION, true, AUTO_CONNECT_TEXT,
              AUTO_CONNECT_LONGTEXT, false )
    add_string( CONNECT_REGEX_OPTION, "system", CONNECT_REGEX_TEXT,
                CONNECT_REGEX_LONGTEXT, false )
    add_sw_gain( )
    set_callbacks( Open, Close )
vlc_module_end ()


static int Start( audio_output_t *p_aout, audio_sample_format_t *restrict fmt )
{
    char psz_name[32];
    struct aout_sys_t *p_sys = p_aout->sys;
    int status = VLC_SUCCESS;
    unsigned int i;
    int i_error;

    p_sys->latency = 0;
    p_sys->paused = VLC_TS_INVALID;

    /* Connect to the JACK server */
    snprintf( psz_name, sizeof(psz_name), "vlc_%d", getpid());
    psz_name[sizeof(psz_name) - 1] = '\0';
    p_sys->p_jack_client = jack_client_open( psz_name,
                                             JackNullOption | JackNoStartServer,
                                             NULL );
    if( p_sys->p_jack_client == NULL )
    {
        msg_Err( p_aout, "failed to connect to JACK server" );
        status = VLC_EGENERIC;
        goto error_out;
    }

    /* Set the process callback */
    jack_set_process_callback( p_sys->p_jack_client, Process, p_aout );
    jack_set_graph_order_callback ( p_sys->p_jack_client, GraphChange, p_aout );

    /* JACK only supports fl32 format */
    fmt->i_format = VLC_CODEC_FL32;
    // TODO add buffer size callback
    p_sys->i_rate = fmt->i_rate = jack_get_sample_rate( p_sys->p_jack_client );

    p_aout->play = Play;
    p_aout->pause = Pause;
    p_aout->flush = Flush;
    p_aout->time_get = TimeGet;
    aout_SoftVolumeStart( p_aout );

    p_sys->i_channels = aout_FormatNbChannels( fmt );
    aout_FormatPrepare(fmt);

    p_sys->p_jack_ports = malloc( p_sys->i_channels *
                                  sizeof(jack_port_t *) );
    if( p_sys->p_jack_ports == NULL )
    {
        status = VLC_ENOMEM;
        goto error_out;
    }

    p_sys->p_jack_buffers = malloc( p_sys->i_channels *
                                    sizeof(jack_sample_t *) );
    if( p_sys->p_jack_buffers == NULL )
    {
        status = VLC_ENOMEM;
        goto error_out;
    }

    const size_t buf_sz = AOUT_MAX_ADVANCE_TIME * fmt->i_rate *
        fmt->i_bytes_per_frame / CLOCK_FREQ;
    p_sys->p_jack_ringbuffer = jack_ringbuffer_create( buf_sz );

    if( p_sys->p_jack_ringbuffer == NULL )
    {
        status = VLC_ENOMEM;
        goto error_out;
    }

    if( jack_ringbuffer_mlock( p_sys->p_jack_ringbuffer ))
    {
        msg_Warn( p_aout, "failed to lock JACK ringbuffer in memory" );
    }

    /* Create the output ports */
    for( i = 0; i < p_sys->i_channels; i++ )
    {
        snprintf( psz_name, sizeof(psz_name), "out_%d", i + 1);
        psz_name[sizeof(psz_name) - 1] = '\0';
        p_sys->p_jack_ports[i] = jack_port_register( p_sys->p_jack_client,
                psz_name, JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0 );

        if( p_sys->p_jack_ports[i] == NULL )
        {
            msg_Err( p_aout, "failed to register a JACK port" );
            status = VLC_EGENERIC;
            goto error_out;
        }
    }

    /* Tell the JACK server we are ready */
    i_error = jack_activate( p_sys->p_jack_client );
    if( i_error )
    {
        msg_Err( p_aout, "failed to activate JACK client (error %d)", i_error );
        status = VLC_EGENERIC;
        goto error_out;
    }

    /* Auto connect ports if we were asked to */
    if( var_InheritBool( p_aout, AUTO_CONNECT_OPTION ) )
    {
        unsigned int i_in_ports;
        char *psz_regex = var_InheritString( p_aout, CONNECT_REGEX_OPTION );
        const char **pp_in_ports = jack_get_ports( p_sys->p_jack_client,
                                                   psz_regex, NULL,
                                                   JackPortIsInput );
        free( psz_regex );
        /* Count the number of returned ports */
        i_in_ports = 0;
        while( pp_in_ports && pp_in_ports[i_in_ports] )
        {
            i_in_ports++;
        }

        /* Tie the output ports to JACK input ports */
        for( i = 0; i_in_ports > 0 && i < p_sys->i_channels; i++ )
        {
            const char* psz_in = pp_in_ports[i % i_in_ports];
            const char* psz_out = jack_port_name( p_sys->p_jack_ports[i] );

            i_error = jack_connect( p_sys->p_jack_client, psz_out, psz_in );
            if( i_error )
            {
                msg_Err( p_aout, "failed to connect port %s to port %s (error %d)",
                         psz_out, psz_in, i_error );
            }
            else
            {
                msg_Dbg( p_aout, "connecting port %s to port %s",
                         psz_out, psz_in );
            }
        }
        free( pp_in_ports );
    }

    msg_Dbg( p_aout, "JACK audio output initialized (%d channels, rate=%d)",
             p_sys->i_channels, fmt->i_rate );

error_out:
    /* Clean up, if an error occurred */
    if( status != VLC_SUCCESS && p_sys != NULL )
    {
        if( p_sys->p_jack_client )
        {
            jack_deactivate( p_sys->p_jack_client );
            jack_client_close( p_sys->p_jack_client );
        }
        if( p_sys->p_jack_ringbuffer )
            jack_ringbuffer_free( p_sys->p_jack_ringbuffer );

        free( p_sys->p_jack_ports );
        free( p_sys->p_jack_buffers );
    }
    return status;
}

static void Play (audio_output_t * p_aout, block_t * p_block)
{
    struct aout_sys_t *p_sys = p_aout->sys;
    jack_ringbuffer_t *rb = p_sys->p_jack_ringbuffer;
    const size_t bytes_per_frame = p_sys->i_channels * sizeof(jack_sample_t);

    while (p_block->i_buffer > 0) {

        /* move data to buffer */
        const size_t write_space = jack_ringbuffer_write_space(rb);
        const size_t bytes = p_block->i_buffer < write_space ?
            p_block->i_buffer : write_space;

        /* If our audio thread is not reading fast enough */
        if( unlikely( bytes == 0 ) ) {
            msg_Warn( p_aout, "%"PRIuPTR " frames of audio dropped",
                    p_block->i_buffer /  bytes_per_frame );
            break;
        }

        jack_ringbuffer_write( rb, (const char *) p_block->p_buffer, bytes );

        p_block->p_buffer += bytes;
        p_block->i_buffer -= bytes;
    }

    block_Release(p_block);
}

/**
 * Pause or unpause playback
 */
static void Pause(audio_output_t *aout, bool paused, mtime_t date)
{
    aout_sys_t *sys = aout->sys;

    if( paused ) {
        sys->paused = date;
    } else {
        date -= sys->paused;
        msg_Dbg(aout, "resuming after %"PRId64" us", date);
        sys->paused = VLC_TS_INVALID;
    }
}

static void Flush(audio_output_t *p_aout, bool wait)
{
    struct aout_sys_t * p_sys = p_aout->sys;
    jack_ringbuffer_t *rb = p_sys->p_jack_ringbuffer;

    /* Sleep if wait was requested */
    if( wait )
    {
        mtime_t delay;
        if (!TimeGet(p_aout, &delay))
            msleep(delay);
    }

    /* reset ringbuffer read and write pointers */
    jack_ringbuffer_reset(rb);
}

static int TimeGet(audio_output_t *p_aout, mtime_t *delay)
{
    struct aout_sys_t * p_sys = p_aout->sys;
    jack_ringbuffer_t *rb = p_sys->p_jack_ringbuffer;
    const size_t bytes_per_frame = p_sys->i_channels * sizeof(jack_sample_t);

    *delay = (p_sys->latency +
            (jack_ringbuffer_read_space(rb) / bytes_per_frame)) *
        CLOCK_FREQ / p_sys->i_rate;

    return 0;
}

/*****************************************************************************
 * Process: callback for JACK
 *****************************************************************************/
int Process( jack_nframes_t i_frames, void *p_arg )
{
    unsigned int i, j, frames_from_rb = 0;
    size_t bytes_read = 0;
    size_t frames_read;
    audio_output_t *p_aout = (audio_output_t*) p_arg;
    struct aout_sys_t *p_sys = p_aout->sys;

    /* Get the next audio data buffer unless paused */

    if( p_sys->paused == VLC_TS_INVALID )
        frames_from_rb = i_frames;

    /* Get the JACK buffers to write to */
    for( i = 0; i < p_sys->i_channels; i++ )
    {
        p_sys->p_jack_buffers[i] = jack_port_get_buffer( p_sys->p_jack_ports[i],
                                                         i_frames );
    }

    /* Copy in the audio data */
    for( j = 0; j < frames_from_rb; j++ )
    {
        for( i = 0; i < p_sys->i_channels; i++ )
        {
            jack_sample_t *p_dst = p_sys->p_jack_buffers[i] + j;
            bytes_read += jack_ringbuffer_read( p_sys->p_jack_ringbuffer,
                    (char *) p_dst, sizeof(jack_sample_t) );
        }
    }

    /* Fill any remaining buffer with silence */
    frames_read = (bytes_read / sizeof(jack_sample_t)) / p_sys->i_channels;
    if( frames_read < i_frames )
    {
        for( i = 0; i < p_sys->i_channels; i++ )
        {
            memset( p_sys->p_jack_buffers[i] + frames_read, 0,
                    sizeof( jack_sample_t ) * (i_frames - frames_read) );
        }
    }

    return 0;
}

/*****************************************************************************
 * GraphChange: callback when JACK reorders it's process graph.
                We update latency information.
 *****************************************************************************/

static int GraphChange( void *p_arg )
{
  audio_output_t *p_aout = (audio_output_t*) p_arg;
  struct aout_sys_t *p_sys = p_aout->sys;
  unsigned int i;
  jack_latency_range_t port_latency;

  p_sys->latency = 0;

  for( i = 0; i < p_sys->i_channels; ++i )
  {
    jack_port_get_latency_range( p_sys->p_jack_ports[i], JackPlaybackLatency,
                                 &port_latency );
    p_sys->latency = __MAX( p_sys->latency, port_latency.max );
  }

  msg_Dbg(p_aout, "JACK graph reordered. Our maximum latency=%d.",
          p_sys->latency);

  return 0;
}

/*****************************************************************************
 * Close: close the JACK client
 *****************************************************************************/
static void Stop( audio_output_t *p_aout )
{
    int i_error;
    struct aout_sys_t *p_sys = p_aout->sys;

    i_error = jack_deactivate( p_sys->p_jack_client );
    if( i_error )
    {
        msg_Err( p_aout, "jack_deactivate failed (error %d)", i_error );
    }

    i_error = jack_client_close( p_sys->p_jack_client );
    if( i_error )
    {
        msg_Err( p_aout, "jack_client_close failed (error %d)", i_error );
    }
    free( p_sys->p_jack_ports );
    free( p_sys->p_jack_buffers );
    jack_ringbuffer_free( p_sys->p_jack_ringbuffer );
}

static int Open(vlc_object_t *obj)
{
    audio_output_t *aout = (audio_output_t *)obj;
    aout_sys_t *sys = calloc(1, sizeof (*sys));

    if( unlikely( sys == NULL ) )
        return VLC_ENOMEM;
    aout->sys = sys;
    aout->start = Start;
    aout->stop = Stop;
    aout_SoftVolumeInit(aout);
    return VLC_SUCCESS;
}

static void Close(vlc_object_t *obj)
{
    audio_output_t *aout = (audio_output_t *)obj;
    aout_sys_t *sys = aout->sys;

    free(sys);
}