mp4.c

/*****************************************************************************
 * mp4.c : MP4 file input module for vlc
 *****************************************************************************
 * Copyright (C) 2001-2004 the VideoLAN team
 * $Id$
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *
 * 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/vlc.h>


#include <vlc_demux.h>
#include <vlc_playlist.h>
#include <vlc_md5.h>
#include <vlc_charset.h>
#include "iso_lang.h"
#include <vlc_meta.h>

#include "libmp4.h"
#include "drms.h"

#ifdef UNDER_CE
#define uint64_t int64_t
#endif

/*****************************************************************************
 * 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( _("MP4 stream demuxer") );
    set_capability( "demux2", 242 );
    set_callbacks( Open, Close );
vlc_module_end();

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int   Demux   ( demux_t * );
static int   DemuxRef( demux_t *p_demux ){ return 0;}
static int   Seek    ( demux_t *, mtime_t );
static int   Control ( demux_t *, int, va_list );

/* Contain all information about a chunk */
typedef struct
{
    uint64_t     i_offset; /* absolute position of this chunk in the file */
    uint32_t     i_sample_description_index; /* index for SampleEntry to use */
    uint32_t     i_sample_count; /* how many samples in this chunk */
    uint32_t     i_sample_first; /* index of the first sample in this chunk */

    /* now provide way to calculate pts, dts, and offset without to
        much memory and with fast acces */

    /* with this we can calculate dts/pts without waste memory */
    uint64_t     i_first_dts;
    uint32_t     *p_sample_count_dts;
    uint32_t     *p_sample_delta_dts;   /* dts delta */

    uint32_t     *p_sample_count_pts;
    int32_t      *p_sample_offset_pts;  /* pts-dts */

    /* TODO if needed add pts
        but quickly *add* support for edts and seeking */

} mp4_chunk_t;

 /* Contain all needed information for read all track with vlc */
typedef struct
{
    unsigned int i_track_ID;/* this should be unique */

    int b_ok;               /* The track is usable */
    int b_enable;           /* is the trak enable by default */
    vlc_bool_t b_selected;  /* is the trak being played */
    vlc_bool_t b_chapter;   /* True when used for chapter only */

    es_format_t fmt;
    es_out_id_t *p_es;

    /* display size only ! */
    int i_width;
    int i_height;

    /* more internal data */
    uint64_t        i_timescale;    /* time scale for this track only */

    /* elst */
    int             i_elst;         /* current elst */
    int64_t         i_elst_time;    /* current elst start time (in movie time scale)*/
    MP4_Box_t       *p_elst;        /* elst (could be NULL) */

    /* give the next sample to read, i_chunk is to find quickly where
      the sample is located */
    uint32_t         i_sample;       /* next sample to read */
    uint32_t         i_chunk;        /* chunk where next sample is stored */
    /* total count of chunk and sample */
    uint32_t         i_chunk_count;
    uint32_t         i_sample_count;

    mp4_chunk_t    *chunk; /* always defined  for each chunk */

    /* sample size, p_sample_size defined only if i_sample_size == 0
        else i_sample_size is size for all sample */
    uint32_t         i_sample_size;
    uint32_t         *p_sample_size; /* XXX perhaps add file offset if take
                                    too much time to do sumations each time*/

    MP4_Box_t *p_stbl;  /* will contain all timing information */
    MP4_Box_t *p_stsd;  /* will contain all data to initialize decoder */
    MP4_Box_t *p_sample;/* point on actual sdsd */

    vlc_bool_t b_drms;
    void      *p_drms;

} mp4_track_t;


struct demux_sys_t
{
    MP4_Box_t    *p_root;      /* container for the whole file */

    mtime_t      i_pcr;

    uint64_t     i_time;         /* time position of the presentation
                                  * in movie timescale */
    uint64_t     i_timescale;    /* movie time scale */
    uint64_t     i_duration;     /* movie duration */
    unsigned int i_tracks;       /* number of tracks */
    mp4_track_t  *track;         /* array of track */

    /* */
    MP4_Box_t    *p_tref_chap;

    /* */
    input_title_t *p_title;
};

/*****************************************************************************
 * Declaration of local function
 *****************************************************************************/
static void MP4_TrackCreate ( demux_t *, mp4_track_t *, MP4_Box_t  *);
static void MP4_TrackDestroy( demux_t *, mp4_track_t * );

static int  MP4_TrackSelect ( demux_t *, mp4_track_t *, mtime_t );
static void MP4_TrackUnselect(demux_t *, mp4_track_t * );

static int  MP4_TrackSeek   ( demux_t *, mp4_track_t *, mtime_t );

static uint64_t MP4_TrackGetPos    ( mp4_track_t * );
static int      MP4_TrackSampleSize( mp4_track_t * );
static int      MP4_TrackNextSample( demux_t *, mp4_track_t * );
static void     MP4_TrackSetELST( demux_t *, mp4_track_t *, int64_t );

static void     MP4_UpdateSeekpoint( demux_t * );

/* Return time in s of a track */
static inline int64_t MP4_TrackGetDTS( demux_t *p_demux, mp4_track_t *p_track )
{
#define chunk p_track->chunk[p_track->i_chunk]

    unsigned int i_index = 0;
    unsigned int i_sample = p_track->i_sample - chunk.i_sample_first;
    int64_t i_dts = chunk.i_first_dts;

    while( i_sample > 0 )
    {
        if( i_sample > chunk.p_sample_count_dts[i_index] )
        {
            i_dts += chunk.p_sample_count_dts[i_index] *
                chunk.p_sample_delta_dts[i_index];
            i_sample -= chunk.p_sample_count_dts[i_index];
            i_index++;
        }
        else
        {
            i_dts += i_sample * chunk.p_sample_delta_dts[i_index];
            i_sample = 0;
            break;
        }
    }

#undef chunk

    /* now handle elst */
    if( p_track->p_elst )
    {
        demux_sys_t         *p_sys = p_demux->p_sys;
        MP4_Box_data_elst_t *elst = p_track->p_elst->data.p_elst;

        /* convert to offset */
        if( ( elst->i_media_rate_integer[p_track->i_elst] > 0 ||
              elst->i_media_rate_fraction[p_track->i_elst] > 0 ) &&
            elst->i_media_time[p_track->i_elst] > 0 )
        {
            i_dts -= elst->i_media_time[p_track->i_elst];
        }

        /* add i_elst_time */
        i_dts += p_track->i_elst_time * p_track->i_timescale /
            p_sys->i_timescale;

        if( i_dts < 0 ) i_dts = 0;
    }

    return I64C(1000000) * i_dts / p_track->i_timescale;
}

static inline int64_t MP4_TrackGetPTSDelta( demux_t *p_demux, mp4_track_t *p_track )
{
    mp4_chunk_t *ck = &p_track->chunk[p_track->i_chunk];
    unsigned int i_index = 0;
    unsigned int i_sample = p_track->i_sample - ck->i_sample_first;

    if( ck->p_sample_count_pts == NULL || ck->p_sample_offset_pts == NULL )
        return -1;

    for( i_index = 0;; i_index++ )
    {
        if( i_sample < ck->p_sample_count_pts[i_index] )
            return ck->p_sample_offset_pts[i_index] * I64C(1000000) /
                   (int64_t)p_track->i_timescale;

        i_sample -= ck->p_sample_count_pts[i_index];
    }
}

static inline int64_t MP4_GetMoviePTS(demux_sys_t *p_sys )
{
    return I64C(1000000) * p_sys->i_time / p_sys->i_timescale;
}

/* Function to lookup the currently playing item */
static vlc_bool_t FindItem( demux_t *p_demux, playlist_t *p_playlist,
                     playlist_item_t **pp_item );

static void LoadChapter( demux_t  *p_demux );

/*****************************************************************************
 * Open: check file and initializes MP4 structures
 *****************************************************************************/
static int Open( vlc_object_t * p_this )
{
    demux_t  *p_demux = (demux_t *)p_this;
    demux_sys_t     *p_sys;

    const uint8_t   *p_peek;

    MP4_Box_t       *p_ftyp;
    MP4_Box_t       *p_rmra;
    MP4_Box_t       *p_mvhd;
    MP4_Box_t       *p_trak;

    unsigned int    i;
    vlc_bool_t      b_seekable;

    /* A little test to see if it could be a mp4 */
    if( stream_Peek( p_demux->s, &p_peek, 8 ) < 8 ) return VLC_EGENERIC;

    switch( VLC_FOURCC( p_peek[4], p_peek[5], p_peek[6], p_peek[7] ) )
    {
        case FOURCC_ftyp:
        case FOURCC_moov:
        case FOURCC_foov:
        case FOURCC_moof:
        case FOURCC_mdat:
        case FOURCC_udta:
        case FOURCC_free:
        case FOURCC_skip:
        case FOURCC_wide:
        case VLC_FOURCC( 'p', 'n', 'o', 't' ):
            break;
         default:
            return VLC_EGENERIC;
    }

    /* I need to seek */
    stream_Control( p_demux->s, STREAM_CAN_SEEK, &b_seekable );
    if( !b_seekable )
    {
        msg_Warn( p_demux, "MP4 plugin discarded (unseekable)" );
        return VLC_EGENERIC;
    }

    /*Set exported functions */
    p_demux->pf_demux = Demux;
    p_demux->pf_control = Control;

    /* create our structure that will contains all data */
    p_demux->p_sys = p_sys = malloc( sizeof( demux_sys_t ) );
    memset( p_sys, 0, sizeof( demux_sys_t ) );

    /* Now load all boxes ( except raw data ) */
    if( ( p_sys->p_root = MP4_BoxGetRoot( p_demux->s ) ) == NULL )
    {
        msg_Warn( p_demux, "MP4 plugin discarded (not a valid file)" );
        goto error;
    }

    MP4_BoxDumpStructure( p_demux->s, p_sys->p_root );

    if( ( p_ftyp = MP4_BoxGet( p_sys->p_root, "/ftyp" ) ) )
    {
        switch( p_ftyp->data.p_ftyp->i_major_brand )
        {
            case( FOURCC_isom ):
                msg_Dbg( p_demux,
                         "ISO Media file (isom) version %d.",
                         p_ftyp->data.p_ftyp->i_minor_version );
                break;
            default:
                msg_Dbg( p_demux,
                         "unrecognized major file specification (%4.4s).",
                          (char*)&p_ftyp->data.p_ftyp->i_major_brand );
                break;
        }
    }
    else
    {
        msg_Dbg( p_demux, "file type box missing (assuming ISO Media file)" );
    }

    /* the file need to have one moov box */
    if( MP4_BoxCount( p_sys->p_root, "/moov" ) <= 0 )
    {
        MP4_Box_t *p_foov = MP4_BoxGet( p_sys->p_root, "/foov" );

        if( !p_foov )
        {
            msg_Err( p_demux, "MP4 plugin discarded (no moov box)" );
            goto error;
        }
        /* we have a free box as a moov, rename it */
        p_foov->i_type = FOURCC_moov;
    }

    if( ( p_rmra = MP4_BoxGet( p_sys->p_root,  "/moov/rmra" ) ) )
    {
        playlist_t *p_playlist;
        playlist_item_t *p_current, *p_item_in_category;
        int        i_count = MP4_BoxCount( p_rmra, "rmda" );
        int        i;
        vlc_bool_t b_play = VLC_FALSE;

        msg_Dbg( p_demux, "detected playlist mov file (%d ref)", i_count );

        p_playlist = pl_Yield( p_demux );
        if( p_playlist )
        {
            b_play = FindItem( p_demux, p_playlist, &p_current );
            p_item_in_category = playlist_ItemToNode( p_playlist, p_current, VLC_TRUE );
            p_current->p_input->i_type = ITEM_TYPE_PLAYLIST;

            for( i = 0; i < i_count; i++ )
            {
                MP4_Box_t *p_rdrf = MP4_BoxGet( p_rmra, "rmda[%d]/rdrf", i );
                char      *psz_ref;
                uint32_t  i_ref_type;

                if( !p_rdrf || !( psz_ref = strdup( p_rdrf->data.p_rdrf->psz_ref ) ) )
                {
                    continue;
                }
                i_ref_type = p_rdrf->data.p_rdrf->i_ref_type;

                msg_Dbg( p_demux, "new ref=`%s' type=%4.4s",
                         psz_ref, (char*)&i_ref_type );

                if( i_ref_type == VLC_FOURCC( 'u', 'r', 'l', ' ' ) )
                {
                    if( strstr( psz_ref, "qt5gateQT" ) )
                    {
                        msg_Dbg( p_demux, "ignoring pseudo ref =`%s'", psz_ref );
                        continue;
                    }
                    if( !strncmp( psz_ref, "http://", 7 ) ||
                        !strncmp( psz_ref, "rtsp://", 7 ) )
                    {
                        ;
                    }
                    else
                    {
                        char *psz_absolute;
                        char *psz_path = strdup( p_demux->psz_path );
                        char *end = strrchr( psz_path, '/' );
                        if( end ) end[1] = '\0';
                        else *psz_path = '\0';

                        asprintf( &psz_absolute, "%s://%s%s",
                                      p_demux->psz_access, psz_path, psz_ref );

                        if( psz_ref ) free( psz_ref );
                        psz_ref = psz_absolute;
                        free( psz_path );
                    }
                    if( p_current )
                    {
                        input_item_t *p_input;
                        msg_Dbg( p_demux, "adding ref = `%s'", psz_ref );
                        p_input = input_ItemNewExt( p_playlist, psz_ref, NULL,
                                            0, NULL, -1 );
                        input_ItemCopyOptions( p_current->p_input, p_input );
                        playlist_BothAddInput( p_playlist, p_input,
                                               p_item_in_category,
                                               PLAYLIST_APPEND, PLAYLIST_END,
                                               NULL, NULL, VLC_FALSE );
                        vlc_gc_decref( p_input );
                    }
                }
                else
                {
                    msg_Err( p_demux, "unknown ref type=%4.4s FIXME (send a bug report)",
                             (char*)&p_rdrf->data.p_rdrf->i_ref_type );
                }
                if( psz_ref ) free( psz_ref );
            }
            if( b_play && p_item_in_category &&
                p_item_in_category->i_children > 0 )
            {
                playlist_Control( p_playlist, PLAYLIST_VIEWPLAY, VLC_TRUE,
                                  p_item_in_category, NULL );
            }
            vlc_object_release( p_playlist );
        }
        else
        {
            msg_Err( p_demux, "can't find playlist" );
        }
    }

    if( !(p_mvhd = MP4_BoxGet( p_sys->p_root, "/moov/mvhd" ) ) )
    {
        if( !p_rmra )
        {
            msg_Err( p_demux, "cannot find /moov/mvhd" );
            goto error;
        }
        else
        {
            msg_Warn( p_demux, "cannot find /moov/mvhd (pure ref file)" );
            p_demux->pf_demux = DemuxRef;
            return VLC_SUCCESS;
        }
    }
    else
    {
        p_sys->i_timescale = p_mvhd->data.p_mvhd->i_timescale;
        p_sys->i_duration = p_mvhd->data.p_mvhd->i_duration;
    }

    if( !( p_sys->i_tracks = MP4_BoxCount( p_sys->p_root, "/moov/trak" ) ) )
    {
        msg_Err( p_demux, "cannot find any /moov/trak" );
        goto error;
    }
    msg_Dbg( p_demux, "found %d track%c",
                        p_sys->i_tracks,
                        p_sys->i_tracks ? 's':' ' );

    /* allocate memory */
    p_sys->track = calloc( p_sys->i_tracks, sizeof( mp4_track_t ) );
    memset( p_sys->track, 0, p_sys->i_tracks * sizeof( mp4_track_t ) );

    /* Search the first chap reference (like quicktime) */
    p_sys->p_tref_chap = NULL;
    for( i = 0; i < p_sys->i_tracks; i++ )
    {
        MP4_Box_t *p_trak = MP4_BoxGet( p_sys->p_root, "/moov/trak[%d]", i );
        MP4_Box_t *p_chap = MP4_BoxGet( p_trak, "tref/chap", i );
        if( !p_chap || p_chap->data.p_tref_generic->i_entry_count <= 0 )
            continue;

        p_sys->p_tref_chap = p_chap;
        break;
    }

    /* now process each track and extract all usefull information */
    for( i = 0; i < p_sys->i_tracks; i++ )
    {
        p_trak = MP4_BoxGet( p_sys->p_root, "/moov/trak[%d]", i );
        MP4_TrackCreate( p_demux, &p_sys->track[i], p_trak );

        if( p_sys->track[i].b_ok && !p_sys->track[i].b_chapter )
        {
            const char *psz_cat;
            switch( p_sys->track[i].fmt.i_cat )
            {
                case( VIDEO_ES ):
                    psz_cat = "video";
                    break;
                case( AUDIO_ES ):
                    psz_cat = "audio";
                    break;
                case( SPU_ES ):
                    psz_cat = "subtitle";
                    break;

                default:
                    psz_cat = "unknown";
                    break;
            }

            msg_Dbg( p_demux, "adding track[Id 0x%x] %s (%s) language %s",
                     p_sys->track[i].i_track_ID, psz_cat,
                     p_sys->track[i].b_enable ? "enable":"disable",
                     p_sys->track[i].fmt.psz_language ?
                     p_sys->track[i].fmt.psz_language : "undef" );
        }
        else if( p_sys->track[i].b_ok && p_sys->track[i].b_chapter )
        {
            msg_Dbg( p_demux, "using track[Id 0x%x] for chapter language %s",
                     p_sys->track[i].i_track_ID,
                     p_sys->track[i].fmt.psz_language ?
                     p_sys->track[i].fmt.psz_language : "undef" );
        }
        else
        {
            msg_Dbg( p_demux, "ignoring track[Id 0x%x]",
                     p_sys->track[i].i_track_ID );
        }
    }

    /* */
    LoadChapter( p_demux );

    return VLC_SUCCESS;

error:
    if( p_sys->p_root )
    {
        MP4_BoxFree( p_demux->s, p_sys->p_root );
    }
    free( p_sys );
    return VLC_EGENERIC;
}

/*****************************************************************************
 * Demux: read packet and send them to decoders
 *****************************************************************************
 * TODO check for newly selected track (ie audio upt to now )
 *****************************************************************************/
static int Demux( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    unsigned int i_track;


    unsigned int i_track_selected;

    /* check for newly selected/unselected track */
    for( i_track = 0, i_track_selected = 0; i_track < p_sys->i_tracks;
         i_track++ )
    {
        mp4_track_t *tk = &p_sys->track[i_track];
        vlc_bool_t b;

        if( !tk->b_ok || tk->b_chapter ||
            ( tk->b_selected && tk->i_sample >= tk->i_sample_count ) )
        {
            continue;
        }

        es_out_Control( p_demux->out, ES_OUT_GET_ES_STATE, tk->p_es, &b );

        if( tk->b_selected && !b )
        {
            MP4_TrackUnselect( p_demux, tk );
        }
        else if( !tk->b_selected && b)
        {
            MP4_TrackSelect( p_demux, tk, MP4_GetMoviePTS( p_sys ) );
        }

        if( tk->b_selected )
        {
            i_track_selected++;
        }
    }

    if( i_track_selected <= 0 )
    {
        p_sys->i_time += __MAX( p_sys->i_timescale / 10 , 1 );
        if( p_sys->i_timescale > 0 )
        {
            int64_t i_length = (mtime_t)1000000 *
                               (mtime_t)p_sys->i_duration /
                               (mtime_t)p_sys->i_timescale;
            if( MP4_GetMoviePTS( p_sys ) >= i_length )
                return 0;
            return 1;
        }

        msg_Warn( p_demux, "no track selected, exiting..." );
        return 0;
    }

    /* */
    MP4_UpdateSeekpoint( p_demux );

    /* first wait for the good time to read a packet */
    es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_sys->i_pcr + 1 );

    p_sys->i_pcr = MP4_GetMoviePTS( p_sys );

    /* we will read 100ms for each stream so ...*/
    p_sys->i_time += __MAX( p_sys->i_timescale / 10 , 1 );

    for( i_track = 0; i_track < p_sys->i_tracks; i_track++ )
    {
        mp4_track_t *tk = &p_sys->track[i_track];

        if( !tk->b_ok || tk->b_chapter || !tk->b_selected || tk->i_sample >= tk->i_sample_count )
            continue;

        while( MP4_TrackGetDTS( p_demux, tk ) < MP4_GetMoviePTS( p_sys ) )
        {
#if 0
            msg_Dbg( p_demux, "tk(%i)=%lld mv=%lld", i_track,
                     MP4_TrackGetDTS( p_demux, tk ),
                     MP4_GetMoviePTS( p_sys ) );
#endif

            if( MP4_TrackSampleSize( tk ) > 0 )
            {
                block_t *p_block;
                int64_t i_delta;

                /* go,go go ! */
                if( stream_Seek( p_demux->s, MP4_TrackGetPos( tk ) ) )
                {
                    msg_Warn( p_demux, "track[0x%x] will be disabled (eof?)",
                              tk->i_track_ID );
                    MP4_TrackUnselect( p_demux, tk );
                    break;
                }

                /* now read pes */
                if( !(p_block =
                         stream_Block( p_demux->s, MP4_TrackSampleSize(tk) )) )
                {
                    msg_Warn( p_demux, "track[0x%x] will be disabled (eof?)",
                              tk->i_track_ID );
                    MP4_TrackUnselect( p_demux, tk );
                    break;
                }

                if( tk->b_drms && tk->p_drms )
                {
                    drms_decrypt( tk->p_drms, (uint32_t*)p_block->p_buffer,
                                  p_block->i_buffer );
                }
                else if( tk->fmt.i_cat == SPU_ES )
                {
                    if( tk->fmt.i_codec == VLC_FOURCC( 's', 'u', 'b', 't' ) &&
                        p_block->i_buffer >= 2 )
                    {
                        uint16_t i_size = GetWBE( p_block->p_buffer );

                        if( i_size + 2 <= p_block->i_buffer )
                        {
                            char *p;
                            /* remove the length field, and append a '\0' */
                            memmove( &p_block->p_buffer[0],
                                     &p_block->p_buffer[2], i_size );
                            p_block->p_buffer[i_size] = '\0';
                            p_block->i_buffer = i_size + 1;

                            /* convert \r -> \n */
                            while( ( p = strchr((char *) p_block->p_buffer, '\r' ) ) )
                            {
                                *p = '\n';
                            }
                        }
                        else
                        {
                            /* Invalid */
                            p_block->i_buffer = 0;
                        }
                    }
                }
                /* dts */
                p_block->i_dts = MP4_TrackGetDTS( p_demux, tk ) + 1;
                /* pts */
                i_delta = MP4_TrackGetPTSDelta( p_demux, tk );
                if( i_delta != -1 )
                    p_block->i_pts = p_block->i_dts + i_delta;
                else if( tk->fmt.i_cat != VIDEO_ES )
                    p_block->i_pts = p_block->i_dts;
                else
                    p_block->i_pts = 0;

                if( !tk->b_drms || ( tk->b_drms && tk->p_drms ) )
                    es_out_Send( p_demux->out, tk->p_es, p_block );
            }

            /* Next sample */
            if( MP4_TrackNextSample( p_demux, tk ) )
                break;
        }
    }

    return 1;
}

static void MP4_UpdateSeekpoint( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    int64_t i_time;
    int i;
    if( !p_sys->p_title )
        return;
    i_time = MP4_GetMoviePTS( p_sys );
    for( i = 0; i < p_sys->p_title->i_seekpoint; i++ )
    {
        if( i_time < p_sys->p_title->seekpoint[i]->i_time_offset )
            break;
    }
    i--;

    if( i != p_demux->info.i_seekpoint && i >= 0 )
    {
        p_demux->info.i_seekpoint = i;
        p_demux->info.i_update |= INPUT_UPDATE_SEEKPOINT;
    }
}
/*****************************************************************************
 * Seek: Got to i_date
******************************************************************************/
static int Seek( demux_t *p_demux, mtime_t i_date )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    unsigned int i_track;

    /* First update update global time */
    p_sys->i_time = i_date * p_sys->i_timescale / 1000000;
    p_sys->i_pcr  = i_date;

    /* Now for each stream try to go to this time */
    for( i_track = 0; i_track < p_sys->i_tracks; i_track++ )
    {
        mp4_track_t *tk = &p_sys->track[i_track];
        MP4_TrackSeek( p_demux, tk, i_date );
    }
    MP4_UpdateSeekpoint( p_demux );
    return VLC_SUCCESS;
}

/*****************************************************************************
 * Control:
 *****************************************************************************/
static int Control( demux_t *p_demux, int i_query, va_list args )
{
    demux_sys_t *p_sys = p_demux->p_sys;

    double f, *pf;
    int64_t i64, *pi64;

    switch( i_query )
    {
        case DEMUX_GET_POSITION:
            pf = (double*)va_arg( args, double * );
            if( p_sys->i_duration > 0 )
            {
                *pf = (double)p_sys->i_time / (double)p_sys->i_duration;
            }
            else
            {
                *pf = 0.0;
            }
            return VLC_SUCCESS;

        case DEMUX_SET_POSITION:
            f = (double)va_arg( args, double );
            if( p_sys->i_timescale > 0 )
            {
                i64 = (int64_t)( f * (double)1000000 *
                                 (double)p_sys->i_duration /
                                 (double)p_sys->i_timescale );
                return Seek( p_demux, i64 );
            }
            else return VLC_SUCCESS;

        case DEMUX_GET_TIME:
            pi64 = (int64_t*)va_arg( args, int64_t * );
            if( p_sys->i_timescale > 0 )
            {
                *pi64 = (mtime_t)1000000 *
                        (mtime_t)p_sys->i_time /
                        (mtime_t)p_sys->i_timescale;
            }
            else *pi64 = 0;
            return VLC_SUCCESS;

        case DEMUX_SET_TIME:
            i64 = (int64_t)va_arg( args, int64_t );
            return Seek( p_demux, i64 );

        case DEMUX_GET_LENGTH:
            pi64 = (int64_t*)va_arg( args, int64_t * );
            if( p_sys->i_timescale > 0 )
            {
                *pi64 = (mtime_t)1000000 *
                        (mtime_t)p_sys->i_duration /
                        (mtime_t)p_sys->i_timescale;
            }
            else *pi64 = 0;
            return VLC_SUCCESS;

        case DEMUX_GET_FPS:
            msg_Warn( p_demux, "DEMUX_GET_FPS unimplemented !!" );
            return VLC_EGENERIC;

        case DEMUX_GET_META:
        {
            vlc_meta_t *p_meta = (vlc_meta_t *)va_arg( args, vlc_meta_t*);
            MP4_Box_t  *p_0xa9xxx;

            MP4_Box_t  *p_udta = MP4_BoxGet( p_sys->p_root, "/moov/udta/meta/ilst" );
            if( p_udta == NULL )
            {
                p_udta = MP4_BoxGet( p_sys->p_root, "/moov/udta" );
                if( p_udta == NULL )
                {
                    return VLC_EGENERIC;
                }
            }

            for( p_0xa9xxx = p_udta->p_first; p_0xa9xxx != NULL;
                 p_0xa9xxx = p_0xa9xxx->p_next )
            {

                if( !p_0xa9xxx || !p_0xa9xxx->data.p_0xa9xxx )
                    continue;

                /* FIXME FIXME: should convert from whatever the character
                 * encoding of MP4 meta data is to UTF-8. */
#define SET(fct) do { char *psz_utf = strdup( p_0xa9xxx->data.p_0xa9xxx->psz_text ? p_0xa9xxx->data.p_0xa9xxx->psz_text : "" ); \
    if( psz_utf ) { EnsureUTF8( psz_utf );  \
                    fct( p_meta, psz_utf ); free( psz_utf ); } } while(0)

                /* XXX Becarefull p_udta can have box that are not 0xa9xx */
                switch( p_0xa9xxx->i_type )
                {
                case FOURCC_0xa9nam: /* Full name */
                    SET( vlc_meta_SetTitle );
                    break;
                case FOURCC_0xa9aut:
                    SET( vlc_meta_SetArtist );
                    break;
                case FOURCC_0xa9ART:
                    SET( vlc_meta_SetArtist );
                    break;
                case FOURCC_0xa9cpy:
                    SET( vlc_meta_SetCopyright );
                    break;