/***************************************************************************** * mpga.c : MPEG-I/II Audio input module for vlc ***************************************************************************** * Copyright (C) 2001-2004 the VideoLAN team * $Id: f920f91003b2c08ed0d05ff3206b2fff2078366b $ * * Authors: Laurent Aimar <fenrir@via.ecp.fr> *          Gildas Bazin <gbazin@videolan.org> * * 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 <vlc_common.h>#include <vlc_plugin.h>#include <vlc_demux.h>#include <vlc_codec.h>#include <vlc_input.h>#define MPGA_PACKET_SIZE 1024/***************************************************************************** * Module descriptor *****************************************************************************/static int  Open ( vlc_object_t * );static void Close( vlc_object_t * );vlc_module_begin();    set_category( CAT_INPUT );    set_subcategory( SUBCAT_INPUT_DEMUX );    set_description( N_("MPEG audio / MP3 demuxer" ) );    set_capability( "demux", 100 );    set_callbacks( Open, Close );    add_shortcut( "mpga" );    add_shortcut( "mp3" );vlc_module_end();/***************************************************************************** * Local prototypes *****************************************************************************/static int Demux  ( demux_t * );static int Control( demux_t *, int, va_list );struct demux_sys_t{    es_out_id_t *p_es;    bool  b_start;    decoder_t   *p_packetizer;    mtime_t     i_pts;    mtime_t     i_time_offset;    int         i_bitrate_avg;  /* extracted from Xing header */    bool b_initial_sync_failed;    int i_xing_frames;    int i_xing_bytes;    int i_xing_bitrate_avg;    int i_xing_frame_samples;};static int HeaderCheck( uint32_t h ){    if( ((( h >> 21 )&0x07FF) != 0x07FF )   /* header sync */        || (((h >> 17)&0x03) == 0 )         /* valid layer ?*/        || (((h >> 12)&0x0F) == 0x0F )        || (((h >> 12)&0x0F) == 0x00 )      /* valid bitrate ? */        || (((h >> 10) & 0x03) == 0x03 )    /* valide sampling freq ? */        || ((h & 0x03) == 0x02 ))           /* valid emphasis ? */    {        return false;    }    return true;}#define MPGA_VERSION( h )   ( 1 - (((h)>>19)&0x01) )#define MPGA_LAYER( h )     ( 3 - (((h)>>17)&0x03) )#define MPGA_MODE(h)        (((h)>> 6)&0x03)static int mpga_frame_samples( uint32_t h ){    switch( MPGA_LAYER(h) )    {        case 0:            return 384;        case 1:            return 1152;        case 2:            return MPGA_VERSION(h) ? 576 : 1152;        default:            return 0;    }}/***************************************************************************** * Open: initializes demux structures *****************************************************************************/static int Open( vlc_object_t * p_this ){    demux_t     *p_demux = (demux_t*)p_this;    demux_sys_t *p_sys;    bool   b_forced = false;    uint32_t     header;    const uint8_t     *p_peek;    if( demux_IsPathExtension( p_demux, ".mp3" ) )        b_forced = true;    if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;    if( !HeaderCheck( header = GetDWBE( p_peek ) ) )    {        bool b_ok = false;        int i_peek;        if( !p_demux->b_force && !b_forced ) return VLC_EGENERIC;        i_peek = stream_Peek( p_demux->s, &p_peek, 8096 );        while( i_peek > 4 )        {            if( HeaderCheck( header = GetDWBE( p_peek ) ) )            {                b_ok = true;                break;            }            p_peek += 1;            i_peek -= 1;        }        if( !b_ok && !p_demux->b_force ) return VLC_EGENERIC;    }    DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;    memset( p_sys, 0, sizeof( demux_sys_t ) );    p_sys->p_es = 0;    p_sys->b_start = true;    /* Load the mpeg audio packetizer */    INIT_APACKETIZER( p_sys->p_packetizer, 'm', 'p', 'g', 'a' );    es_format_Init( &p_sys->p_packetizer->fmt_out, UNKNOWN_ES, 0 );    LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "mpga" );    /* Xing header */    if( HeaderCheck( header ) )    {        int i_xing, i_skip;        const uint8_t *p_xing;        if( ( i_xing = stream_Peek( p_demux->s, &p_xing, 1024 ) ) < 21 )            return VLC_SUCCESS; /* No header */        if( MPGA_VERSION( header ) == 0 )        {            i_skip = MPGA_MODE( header ) != 3 ? 36 : 21;        }        else        {            i_skip = MPGA_MODE( header ) != 3 ? 21 : 13;        }        if( i_skip + 8 < i_xing && !strncmp( (char *)&p_xing[i_skip], "Xing", 4 ) )        {            unsigned int i_flags = GetDWBE( &p_xing[i_skip+4] );            p_xing += i_skip + 8;            i_xing -= i_skip + 8;            i_skip = 0;            if( i_flags&0x01 && i_skip + 4 <= i_xing )   /* XING_FRAMES */            {                p_sys->i_xing_frames = GetDWBE( &p_xing[i_skip] );                i_skip += 4;            }            if( i_flags&0x02 && i_skip + 4 <= i_xing )   /* XING_BYTES */            {                p_sys->i_xing_bytes = GetDWBE( &p_xing[i_skip] );                i_skip += 4;            }            if( i_flags&0x04 )   /* XING_TOC */            {                i_skip += 100;            }            // FIXME: doesn't return the right bitrage average, at least            // with some MP3's            if( i_flags&0x08 && i_skip + 4 <= i_xing )   /* XING_VBR */            {                p_sys->i_xing_bitrate_avg = GetDWBE( &p_xing[i_skip] );                msg_Dbg( p_demux, "xing vbr value present (%d)",                         p_sys->i_xing_bitrate_avg );            }            if( p_sys->i_xing_frames > 0 && p_sys->i_xing_bytes > 0 )            {                p_sys->i_xing_frame_samples = mpga_frame_samples( header );                msg_Dbg( p_demux, "xing frames&bytes value present "                         "(%d bytes, %d frames, %d samples/frame)",                         p_sys->i_xing_bytes, p_sys->i_xing_frames,                         p_sys->i_xing_frame_samples );            }        }    }    if( p_sys->i_xing_bytes && p_sys->i_xing_frames &&        p_sys->i_xing_frame_samples )    {        p_sys->i_bitrate_avg = p_sys->i_xing_bytes * INT64_C(8) *            p_sys->p_packetizer->fmt_out.audio.i_rate /            p_sys->i_xing_frames / p_sys->i_xing_frame_samples;    }    return VLC_SUCCESS;}/***************************************************************************** * Demux: reads and demuxes data packets ***************************************************************************** * Returns -1 in case of error, 0 in case of EOF, 1 otherwise *****************************************************************************/static int Demux( demux_t *p_demux ){    demux_sys_t *p_sys = p_demux->p_sys;    block_t *p_block_in, *p_block_out;    if( ( p_block_in = stream_Block( p_demux->s, MPGA_PACKET_SIZE ) ) == NULL )    {        return 0;    }    p_block_in->i_pts = p_block_in->i_dts = p_sys->b_start || p_sys->b_initial_sync_failed ? 1 : 0;    p_sys->b_initial_sync_failed = p_sys->b_start; /* Only try to resync once */    while( ( p_block_out = p_sys->p_packetizer->pf_packetize( p_sys->p_packetizer, &p_block_in ) ) )    {        p_sys->b_initial_sync_failed = false;        while( p_block_out )        {            block_t *p_next = p_block_out->p_next;            if( !p_sys->p_es )            {                p_sys->p_packetizer->fmt_out.b_packetized = true;                p_sys->p_es = es_out_Add( p_demux->out,                                          &p_sys->p_packetizer->fmt_out);                if( p_sys->i_bitrate_avg <= 0 )                    p_sys->i_bitrate_avg = p_sys->p_packetizer->fmt_out.i_bitrate;            }            p_sys->i_pts = p_block_out->i_pts;            /* Correct timestamp */            p_block_out->i_pts += p_sys->i_time_offset;            p_block_out->i_dts += p_sys->i_time_offset;            es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );            es_out_Send( p_demux->out, p_sys->p_es, p_block_out );            p_block_out = p_next;        }    }    if( p_sys->b_initial_sync_failed )        msg_Dbg( p_demux, "did not sync on first block" );    p_sys->b_start = false;    return 1;}/***************************************************************************** * Close: frees unused data *****************************************************************************/static void Close( vlc_object_t * p_this ){    demux_t     *p_demux = (demux_t*)p_this;    demux_sys_t *p_sys = p_demux->p_sys;    DESTROY_PACKETIZER( p_sys->p_packetizer );    free( p_sys );}/***************************************************************************** * Control: *****************************************************************************/static int Control( demux_t *p_demux, int i_query, va_list args ){    demux_sys_t *p_sys  = p_demux->p_sys;    int64_t *pi64;    bool *pb_bool;    int i_ret;    va_list args_save;    va_copy ( args_save, args );    switch( i_query )    {        case DEMUX_HAS_UNSUPPORTED_META:            pb_bool = (bool*)va_arg( args, bool* );            *pb_bool = true;            return VLC_SUCCESS;        case DEMUX_GET_TIME:            pi64 = (int64_t*)va_arg( args, int64_t * );            *pi64 = p_sys->i_pts + p_sys->i_time_offset;            return VLC_SUCCESS;        case DEMUX_GET_LENGTH:            i_ret = demux_vaControlHelper( p_demux->s, 0, -1,                                            p_sys->i_bitrate_avg, 1, i_query,                                            args );            /* No bitrate, we can't have it precisely, but we can compute             * a raw approximation with time/position */            if( i_ret && !p_sys->i_bitrate_avg )            {                float f_pos = (double)(uint64_t)( stream_Tell( p_demux->s ) ) /                              (double)(uint64_t)( stream_Size( p_demux->s ) );                /* The first few seconds are guaranteed to be very whacky,                 * don't bother trying ... Too bad */                if( f_pos < 0.01 ||                    (p_sys->i_pts + p_sys->i_time_offset) < 8000000 )                    return VLC_EGENERIC;                pi64 = (int64_t *)va_arg( args_save, int64_t * );                *pi64 = (p_sys->i_pts + p_sys->i_time_offset) / f_pos;                return VLC_SUCCESS;            }            va_end( args_save );            return i_ret;        case DEMUX_SET_TIME:            /* FIXME TODO: implement a high precision seek (with mp3 parsing)             * needed for multi-input */        default:            i_ret = demux_vaControlHelper( p_demux->s, 0, -1,                                            p_sys->i_bitrate_avg, 1, i_query,                                            args );            if( !i_ret && p_sys->i_bitrate_avg > 0 &&                (i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME) )            {                int64_t i_time = INT64_C(8000000) * stream_Tell(p_demux->s) /                    p_sys->i_bitrate_avg;                /* Fix time_offset */                if( i_time >= 0 )                    p_sys->i_time_offset = i_time - p_sys->i_pts;            }            return i_ret;    }}