vlc_demux.h

Go to the documentation of this file.

/*****************************************************************************
 * vlc_demux.h: Demuxer descriptor, queries and methods
 *****************************************************************************
 * Copyright (C) 1999-2005 VLC authors and VideoLAN
 * $Id: a5b525710ca3f41843e7a14298dbe06d4a7df06d $
 *
 * 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 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.
 *****************************************************************************/

#ifndef VLC_DEMUX_H
#define VLC_DEMUX_H 1

/**
 * \file
 * This files defines functions and structures used by demux objects in vlc
 */

#include <vlc_es.h>
#include <vlc_stream.h>
#include <vlc_es_out.h>

/**
 * \defgroup demux Demux
 * @{
 */

struct demux_t
{
    VLC_COMMON_MEMBERS

    /* Module properties */
    module_t    *p_module;

    /* eg informative but needed (we can have access+demux) */
    char        *psz_access;
    char        *psz_demux;
    char        *psz_location;
    char        *psz_file;

    /* input stream */
    stream_t    *s;     /* NULL in case of a access+demux in one */

    /* es output */
    es_out_t    *out;   /* our p_es_out */

    /* set by demuxer */
    int (*pf_demux)  ( demux_t * );   /* demux one frame only */
    int (*pf_control)( demux_t *, int i_query, va_list args);

    /* Demux has to maintain them uptodate
     * when it is responsible of seekpoint/title */
    struct
    {
        unsigned int i_update;  /* Demux sets them on change,
                                   Input removes them once take into account*/
        /* Seekpoint/Title at demux level */
        int          i_title;       /* idem, start from 0 (could be menu) */
        int          i_seekpoint;   /* idem, start from 0 */
    } info;
    demux_sys_t *p_sys;

    /* Weak link to parent input */
    input_thread_t *p_input;
};


/* demux_meta_t is returned by "meta reader" module to the demuxer */
typedef struct demux_meta_t
{
    VLC_COMMON_MEMBERS
    demux_t *p_demux; /** FIXME: use stream_t instead? */
    input_item_t *p_item; /***< the input item that is being read */

    vlc_meta_t *p_meta;                 /**< meta data */

    int i_attachments;                  /**< number of attachments */
    input_attachment_t **attachments;    /**< array of attachments */
} demux_meta_t;

enum demux_query_e
{
    /* I. Common queries to access_demux and demux */
    /* POSITION double between 0.0 and 1.0 */
    DEMUX_GET_POSITION,         /* arg1= double *       res=    */
    DEMUX_SET_POSITION,         /* arg1= double arg2= bool b_precise    res=can fail    */

    /* LENGTH/TIME in microsecond, 0 if unknown */
    DEMUX_GET_LENGTH,           /* arg1= int64_t *      res=    */
    DEMUX_GET_TIME,             /* arg1= int64_t *      res=    */
    DEMUX_SET_TIME,             /* arg1= int64_t arg2= bool b_precise   res=can fail    */

    /* TITLE_INFO only if more than 1 title or 1 chapter */
    DEMUX_GET_TITLE_INFO,       /* arg1=input_title_t*** arg2=int*
                                   arg3=int*pi_title_offset(0), arg4=int*pi_seekpoint_offset(0) can fail */
    /* TITLE/SEEKPOINT, only when TITLE_INFO succeed */
    DEMUX_SET_TITLE,            /* arg1= int            can fail */
    DEMUX_SET_SEEKPOINT,        /* arg1= int            can fail */

    /* DEMUX_SET_GROUP only a hint for demuxer (mainly DVB) to allow not
     * reading everything (you should not use this to call es_out_Control)
     * if you don't know what to do with it, just IGNORE it, it is safe(r)
     * -1 means all group, 0 default group (first es added) */
    DEMUX_SET_GROUP,            /* arg1= int, arg2=const vlc_list_t *   can fail */

    /* Ask the demux to demux until the given date at the next pf_demux call
     * but not more (and not less, at the precision available of course).
     * XXX: not mandatory (except for subtitle demux) but will help a lot
     * for multi-input
     */
    DEMUX_SET_NEXT_DEMUX_TIME,  /* arg1= int64_t *      can fail */
    /* FPS for correct subtitles handling */
    DEMUX_GET_FPS,              /* arg1= double *       res=can fail    */

    /* Meta data */
    DEMUX_GET_META,             /* arg1= vlc_meta_t **  res=can fail    */
    DEMUX_HAS_UNSUPPORTED_META, /* arg1= bool *   res can fail    */

    /* Attachments */
    DEMUX_GET_ATTACHMENTS,      /* arg1=input_attachment_t***, int* res=can fail */

    /* RECORD you are ensured that it is never called twice with the same state
     * you should accept it only if the stream can be recorded without
     * any modification or header addition. */
    DEMUX_CAN_RECORD,           /* arg1=bool*   res=can fail(assume false) */
    DEMUX_SET_RECORD_STATE,     /* arg1=bool    res=can fail */


    /* II. Specific access_demux queries */
    /* PAUSE you are ensured that it is never called twice with the same state */
    DEMUX_CAN_PAUSE = 0x1000,   /* arg1= bool*    can fail (assume false)*/
    DEMUX_SET_PAUSE_STATE,      /* arg1= bool     can fail */

    DEMUX_GET_PTS_DELAY,        /* arg1= int64_t*       cannot fail */

    /* DEMUX_CAN_CONTROL_PACE returns true (*pb_pace) if we can read the
     * data at our pace */
    DEMUX_CAN_CONTROL_PACE,     /* arg1= bool*pb_pace    can fail (assume false) */

    /* DEMUX_CAN_CONTROL_RATE is called only if DEMUX_CAN_CONTROL_PACE has returned false.
     * *pb_rate should be true when the rate can be changed (using DEMUX_SET_RATE)
     * *pb_ts_rescale should be true when the timestamps (pts/dts/pcr) have to be rescaled */
    DEMUX_CAN_CONTROL_RATE,     /* arg1= bool*pb_rate arg2= bool*pb_ts_rescale  can fail(assume false) */
    /* DEMUX_SET_RATE is called only if DEMUX_CAN_CONTROL_RATE has returned true.
     * It should return the value really used in *pi_rate */
    DEMUX_SET_RATE,             /* arg1= int*pi_rate                                        can fail */

    DEMUX_CAN_SEEK,            /* arg1= bool*    can fail (assume false)*/
};

VLC_API int demux_vaControlHelper( stream_t *, int64_t i_start, int64_t i_end, int64_t i_bitrate, int i_align, int i_query, va_list args );

/*************************************************************************
 * Miscellaneous helpers for demuxers
 *************************************************************************/

VLC_USED
static inline bool demux_IsPathExtension( demux_t *p_demux, const char *psz_extension )
{
    if( !p_demux->psz_file )
        return false;

    const char *psz_ext = strrchr ( p_demux->psz_file, '.' );
    if( !psz_ext || strcasecmp( psz_ext, psz_extension ) )
        return false;
    return true;
}

VLC_USED
static inline bool demux_IsForced( demux_t *p_demux, const char *psz_name )
{
   if( !p_demux->psz_demux || strcmp( p_demux->psz_demux, psz_name ) )
        return false;
    return true;
}

/**
 * This function will create a packetizer suitable for a demuxer that parses
 * elementary stream.
 *
 * The provided es_format_t will be cleaned on error or by
 * demux_PacketizerDestroy.
 */
VLC_API decoder_t * demux_PacketizerNew( demux_t *p_demux, es_format_t *p_fmt, const char *psz_msg ) VLC_USED;

/**
 * This function will destroy a packetizer create by demux_PacketizerNew.
 */
VLC_API void demux_PacketizerDestroy( decoder_t *p_packetizer );

/**
 * This function will return the parent input of this demux.
 * It is retained. Can return NULL.
 */
VLC_API input_thread_t * demux_GetParentInput( demux_t *p_demux ) VLC_USED;

/* */
#define DEMUX_INIT_COMMON() do {            \
    p_demux->pf_control = Control;          \
    p_demux->pf_demux = Demux;              \
    p_demux->p_sys = calloc( 1, sizeof( demux_sys_t ) ); \
    if( !p_demux->p_sys ) return VLC_ENOMEM;\
    } while(0)

/**
 * @}
 */

#endif