[vlc-devel] [PATCH] New mpg123 audio converter
Rafaël Carré
funman at videolan.org
Tue Sep 3 13:59:56 CEST 2013
Hi,
Le 03/09/2013 13:01, Ludovic Fauvet a écrit :
> As of now, mpg123 is licensed under the LGPL 2.1. In terms of performances it
> should perform better than the existing libmad module because of various
> assembly optimizations.
> ---
> configure.ac | 6 +
> modules/audio_filter/Modules.am | 1 +
> modules/audio_filter/converter/mpg123.c | 276 ++++++++++++++++++++++++++++++++
> 3 files changed, 283 insertions(+)
> create mode 100644 modules/audio_filter/converter/mpg123.c
>
> diff --git a/configure.ac b/configure.ac
> index 0f6ea2a..ee2fcad 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2264,6 +2264,12 @@ then
> fi
> fi
>
> +dnl mpg123 plugin
> +dnl
> +dnl
> +PKG_ENABLE_MODULES_VLC([MPG123], [mpg123], [libmpg123], [libmpg123 decoder support], [auto])
> +
> +
>
> AC_ARG_ENABLE(merge-ffmpeg,
> [ --enable-merge-ffmpeg merge FFmpeg-based plugins (default disabled)],, [
> diff --git a/modules/audio_filter/Modules.am b/modules/audio_filter/Modules.am
> index d3454e9..2e41236 100644
> --- a/modules/audio_filter/Modules.am
> +++ b/modules/audio_filter/Modules.am
> @@ -51,6 +51,7 @@ SOURCES_a52tofloat32 = converter/a52tofloat32.c
> SOURCES_dtstospdif = converter/dtstospdif.c
> SOURCES_dtstofloat32 = converter/dtstofloat32.c
> SOURCES_mpgatofixed32 = converter/mpgatofixed32.c
> +SOURCES_mpg123 = converter/mpg123.c
> libaudio_format_plugin_la_SOURCES = converter/format.c
> libaudio_format_plugin_la_CFLAGS = $(AM_CFLAGS)
> libaudio_format_plugin_la_LIBADD = $(AM_LIBADD) $(LIBM)
> diff --git a/modules/audio_filter/converter/mpg123.c b/modules/audio_filter/converter/mpg123.c
> new file mode 100644
> index 0000000..47131aa
> --- /dev/null
> +++ b/modules/audio_filter/converter/mpg123.c
> @@ -0,0 +1,276 @@
> +/*****************************************************************************
> + * mpgatofloat32_mpg123.c: MPEG-1 & 2 audio layer I, II, III + MPEG 2.5
filename out of date, though I wonder if it's really useful to put the
filename here.
> + * decoder, using MPG123
> + *****************************************************************************
> + * Copyright (C) 2001-2013 VLC authors and VideoLAN
> + *
> + * Authors: Christophe Massiot <massiot at via.ecp.fr>
> + * Jean-Paul Saman <jpsaman _at_ videolan _dot_ org>
> + * William Hahne <will07c5 at gmail.com>
> + * Ludovic Fauvet <etix at videolan.org>
> + *
> + * 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.
> + *****************************************************************************/
> +
> +/*****************************************************************************
> + * Preamble
> + *****************************************************************************/
> +
> +#include <mpg123.h>
> +
> +#ifdef HAVE_CONFIG_H
> +# include "config.h"
> +#endif
> +#include <assert.h>
> +
> +#include <vlc_common.h>
> +#include <vlc_plugin.h>
> +#include <vlc_aout.h>
> +#include <vlc_block.h>
> +#include <vlc_filter.h>
> +
> +/*****************************************************************************
> + * Local prototypes
> + *****************************************************************************/
> +static int OpenFilter ( vlc_object_t * );
> +static void CloseFilter( vlc_object_t * );
> +static block_t *Convert( filter_t *, block_t * );
> +static int InitMPG123( void );
> +static void ExitMPG123( void );
> +
> +static unsigned int mpg123_refcount = 0;
> +static vlc_mutex_t mpg123_mutex = VLC_STATIC_MUTEX;
Depending on what mpg123_{init,exit} are doing you could also use gcc
constructor/destructor function attributes so those functions are called
exactly once when the .so are loaded / unloaded.
This simplifies the code, and the drawback is those functions are called
even if we don't use the module.
> +
> +/*****************************************************************************
> + * Local structures
> + *****************************************************************************/
> +struct filter_sys_t
> +{
> + mpg123_handle * p_handle;
> + int i_reject_count;
> +};
> +
> +/*****************************************************************************
> + * Module descriptor
> + *****************************************************************************/
> +vlc_module_begin ()
> + set_category( CAT_INPUT )
> + set_subcategory( SUBCAT_INPUT_ACODEC )
> + set_description( N_("MPEG audio decoder using mpg123") )
> + set_capability( "audio converter", 123 )
> + set_callbacks( OpenFilter, CloseFilter )
> +vlc_module_end ()
> +
> +/*****************************************************************************
> + * DoWork: decode an MPEG audio frame.
> + *****************************************************************************/
> +static void DoWork( filter_t * p_filter,
> + block_t * p_in_buf, block_t * p_out_buf )
> +{
> + uint8_t *p_buffer;
> + size_t i_size;
> + filter_sys_t *p_sys = p_filter->p_sys;
> +
> + p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
> + p_out_buf->i_buffer = p_in_buf->i_nb_samples * sizeof(float) *
> + aout_FormatNbChannels( &p_filter->fmt_out.audio );
> +
> +
> + /* Ignore the last 8 bytes due to a hack for libmad */
> + /* FIXME: This hack should be removed somehow --etix */
> + if ( p_in_buf->i_buffer < 8 )
> + return;
Can you explain a bit more here? Is it still related to libmad?
> + int i_err = mpg123_feed( p_sys->p_handle, p_in_buf->p_buffer,
> + p_in_buf->i_buffer - 8 );
> +
> + /* Do the actual decoding now */
> + if ( i_err != MPG123_OK || mpg123_decode_frame( p_sys->p_handle,
> + NULL, &p_buffer, &i_size ) != MPG123_OK )
> + {
> + msg_Warn( p_filter, "mpg123 error: %s",
> + mpg123_strerror( p_sys->p_handle ) );
> + p_sys->i_reject_count = 3;
> + }
> + else if( p_in_buf->i_flags & BLOCK_FLAG_DISCONTINUITY )
> + {
> + p_sys->i_reject_count = 3;
I think decoding can be skipped in this case since we're outputting 0s.
> + }
> +
> + if( p_sys->i_reject_count > 0 )
> + {
> + memset( p_out_buf->p_buffer, 0, p_out_buf->i_buffer );
> + p_sys->i_reject_count--;
> + return;
> + }
> +
> + assert( p_out_buf->i_size >= i_size );
> + memcpy( p_out_buf->p_buffer, p_buffer, i_size );
> +}
> +
> +static block_t *Convert( filter_t *p_filter, block_t *p_block )
> +{
> + if( !p_block || !p_block->i_nb_samples )
> + {
> + if( p_block )
> + block_Release( p_block );
> + return NULL;
> + }
I think it would be more readable by splitting the 2 parts of the if
> + size_t i_out_size = p_block->i_nb_samples *
> + p_filter->fmt_out.audio.i_bitspersample *
> + p_filter->fmt_out.audio.i_channels / 8;
> +
> + block_t *p_out = block_Alloc( i_out_size );
> + if( unlikely( !p_out ) )
> + {
> + msg_Warn( p_filter, "can't get output buffer" );
msg_ not needed?
> + block_Release( p_block );
> + return NULL;
> + }
> +
> + p_out->i_nb_samples = p_block->i_nb_samples;
> + p_out->i_dts = p_block->i_dts;
> + p_out->i_pts = p_block->i_pts;
> + p_out->i_length = p_block->i_length;
> +
> + DoWork( p_filter, p_block, p_out );
> +
> + block_Release( p_block );
> +
> + return p_out;
> +}
> +
> +/*****************************************************************************
> + * OpenFilter:
> + *****************************************************************************/
> +static int OpenFilter( vlc_object_t *p_this )
> +{
> + filter_t *p_filter = (filter_t *)p_this;
> + filter_sys_t *p_sys;
> +
> + if( p_filter->fmt_in.i_codec != VLC_CODEC_MPGA &&
> + p_filter->fmt_in.i_codec != VLC_FOURCC('m','p','g','3') )
> + return VLC_EGENERIC;
> +
> + if( !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio, &p_filter->fmt_out.audio ) )
> + return VLC_EGENERIC;
> +
> + if( p_filter->fmt_out.audio.i_format != VLC_CODEC_FL32 )
> + return VLC_EGENERIC;
> +
> + /* Allocate the memory needed to store the module's structure */
> + p_sys = p_filter->p_sys = malloc( sizeof(filter_sys_t) );
> + if( p_sys == NULL )
> + return VLC_EGENERIC;
> +
> + /* Initialize libmpg123 */
> + if( InitMPG123() != MPG123_OK ||
> + ( p_sys->p_handle = mpg123_new( NULL, NULL ) ) == NULL )
> + {
ExitMPG123 shouldn't be called in the first case.
> + goto error;
> + }
> +
> + /* Open a new bitstream */
> + if( mpg123_open_feed( p_sys->p_handle ) != MPG123_OK )
> + {
> + msg_Err( p_this, "mpg123 error: can't open feed" );
> + mpg123_delete( p_sys->p_handle );
> + goto error;
> + }
> +
> + /* Disable resync stream after error */
> + mpg123_param( p_sys->p_handle, MPG123_ADD_FLAGS, MPG123_NO_RESYNC, 0 );
> +
> + /* Setup output format */
> + mpg123_format_none( p_sys->p_handle );
> +
> + if( MPG123_OK != mpg123_format( p_sys->p_handle,
> + p_filter->fmt_in.audio.i_rate,
> + MPG123_MONO | MPG123_STEREO,
> + MPG123_ENC_FLOAT_32 ) )
> + {
> + msg_Err( p_this, "mpg123 error: %s",
> + mpg123_strerror( p_sys->p_handle ) );
> + mpg123_close( p_sys->p_handle );
> + mpg123_delete( p_sys->p_handle );
> + goto error;
> + }
> +
> + p_sys->i_reject_count = 0;
> + p_filter->pf_audio_filter = Convert;
> + p_filter->fmt_out.audio.i_format = p_filter->fmt_out.i_codec;
> + p_filter->fmt_out.audio.i_bitspersample =
> + aout_BitsPerSample( p_filter->fmt_out.i_codec );
> +
> + msg_Dbg( p_this, "%4.4s->%4.4s, bits per sample: %i",
> + (char *)&p_filter->fmt_in.i_codec,
> + (char *)&p_filter->fmt_out.i_codec,
> + p_filter->fmt_in.audio.i_bitspersample );
> +
> + return VLC_SUCCESS;
> +error:
> + ExitMPG123();
> + free( p_sys );
> + return VLC_EGENERIC;
> +}
> +
> +/*****************************************************************************
> + * CloseFilter : deallocate data structures
> + *****************************************************************************/
> +static void CloseFilter( vlc_object_t *p_this )
> +{
> + filter_t *p_filter = (filter_t *)p_this;
> + filter_sys_t *p_sys = p_filter->p_sys;
> +
> + mpg123_close( p_sys->p_handle );
> + mpg123_delete( p_sys->p_handle );
> + ExitMPG123();
> + free( p_sys );
> +}
> +
> +/*****************************************************************************
> + * InitMPG123 : initialize the mpg123 library (reentrant)
> + *****************************************************************************/
> +static int InitMPG123( void )
> +{
> + int i_ret;
> + vlc_mutex_lock( &mpg123_mutex );
> + if( mpg123_refcount > 0 )
> + {
> + mpg123_refcount++;
> + vlc_mutex_unlock( &mpg123_mutex );
> + return MPG123_OK;
> + }
> + if( ( i_ret = mpg123_init() ) == MPG123_OK )
> + mpg123_refcount++;
> + vlc_mutex_unlock( &mpg123_mutex );
> + return i_ret;
> +}
> +
> +/*****************************************************************************
> + * ExitMPG123 : close down the mpg123 library (reentrant)
> + *****************************************************************************/
> +static void ExitMPG123( void )
> +{
> + vlc_mutex_lock( &mpg123_mutex );
> + if( mpg123_refcount > 1 )
> + {
> + mpg123_refcount--;
> + vlc_mutex_unlock( &mpg123_mutex );
> + return;
> + }
Missing mpg123_refcount--
> + mpg123_exit();
> + vlc_mutex_unlock( &mpg123_mutex );
> +}
>
More information about the vlc-devel
mailing list