system.h

VLC媒体播放程序

/*****************************************************************************
 * system.h: MPEG demultiplexing.
 *****************************************************************************
 * Copyright (C) 1999-2002 VideoLAN
 * $Id: system.h,v 1.14 2004/01/15 22:15:40 gbazin Exp $
 *
 * Authors: Christophe Massiot <[e-mail]>
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*
 * Optional MPEG demultiplexing
 */

/*****************************************************************************
 * Constants
 *****************************************************************************/
#define TS_PACKET_SIZE      188                       /* Size of a TS packet */
#define TS_SYNC_CODE        0x47                /* First byte of a TS packet */
#define TS_SYNC_CODES_MIN   5        /* Min number of sync codes to look for */
#define PSI_SECTION_SIZE    4096            /* Maximum size of a PSI section */

#define PAT_UNINITIALIZED    (1 << 6)
#define PMT_UNINITIALIZED    (1 << 6)

#define PSI_IS_PAT          0x00
#define PSI_IS_PMT          0x01
#define UNKNOWN_PSI         0xff

/* ES streams types - see ISO/IEC 13818-1 table 2-29 numbers.
 * these values are used in mpeg_system.c, and in
 * the following plugins: mpeg_ts, mpeg_ts_dvbpsi, satellite. */
#define MPEG1_VIDEO_ES      0x01
#define MPEG2_VIDEO_ES      0x02
#define MPEG1_AUDIO_ES      0x03
#define MPEG2_AUDIO_ES      0x04
/* This one is "private PES". It may carry teletext, DVD subtitles, A52
 * We have to check for the presence of a descriptor to have the codec */
#define PES_PRIVATE_ES      0x06

/* ISO/IEC 13818-7 Audio with ADTS transport syntax */
#define AAC_ADTS_AUDIO_ES   0x0F

#define MPEG4_VIDEO_ES      0x10
#define MPEG4_AUDIO_ES      0x11

#define MPEG2_MOTO_VIDEO_ES 0x80
#define A52_AUDIO_ES        0x81
/* These ones might violate the usage : */
#define DVD_SPU_ES          0x82
#define LPCM_AUDIO_ES       0x83
#define SDDS_AUDIO_ES       0x84
#define DTS_AUDIO_ES        0x85
/* These ones are only here to work around a bug in VLS - VLS doesn't
 * skip the first bytes of the PES payload (stream private ID) when
 * streaming. This is incompatible with all equipments. 'B' is for
 * buggy. Please note that they are associated with FOURCCs '***b'.
 * --Meuuh 2002-08-30
 */
#define A52B_AUDIO_ES       0x91
#define DVDB_SPU_ES         0x92
#define LPCMB_AUDIO_ES      0x93

#define MSCODEC_VIDEO_ES    0xa0

/****************************************************************************
 * psi_callback_t
 ****************************************************************************
 * Used by TS demux to handle a PSI, either with the builtin decoder, either
 * with a library such as libdvbpsi
 ****************************************************************************/
typedef void( * psi_callback_t )(
        input_thread_t  * p_input,
        data_packet_t   * p_data,
        es_descriptor_t * p_es,
        vlc_bool_t        b_unit_start );


/****************************************************************************
 * mpeg_demux_t
 ****************************************************************************
 * Demux callbacks exported by the helper plugin
 ****************************************************************************/
typedef struct mpeg_demux_t
{
    module_t * p_module;

    ssize_t           (*pf_read_ps)  ( input_thread_t *, data_packet_t ** );
    es_descriptor_t * (*pf_parse_ps) ( input_thread_t *, data_packet_t * );
    void              (*pf_demux_ps) ( input_thread_t *, data_packet_t * );

    ssize_t           (*pf_read_ts)  ( input_thread_t *, data_packet_t ** );
    void              (*pf_demux_ts) ( input_thread_t *, data_packet_t *,
                                       psi_callback_t );

    /* 
       rocky:
     i_cur_mux_rate and cur_scr_time below are a bit of a hack.
     
     Background: VLC uses the System Clock Reference (SCR) of a PACK
     header to read the stream at the right pace (contrary to other
     players like xine/mplayer which don't use this info and
     synchronise everything on the audio output clock).
     
     The popular SVCD/VCD subtitling WinSubMux does not renumber the
     SCRs when merging subtitles into the PES. Perhaps other
     multipliexing tools are equally faulty. Until such time as
     WinSubMux is fixed or other tools become available and widely
     used, we will cater to the WinSubMux kind of buggy stream. The
     hack here delays using the PACK SCR until the first PES that
     would need it is received. For this we need to temporarily save
     this information in the variables below.
    */
    uint32_t i_cur_mux_rate;
    mtime_t  cur_scr_time;

} mpeg_demux_t;

/*****************************************************************************
 * psi_section_t
 *****************************************************************************
 * Describes a PSI section. Beware, it doesn't contain pointers to the TS
 * packets that contain it as for a PES, but the data themselves
 *****************************************************************************/
typedef struct psi_section_t
{
    byte_t                  buffer[PSI_SECTION_SIZE];

    uint8_t                 i_section_number;
    uint8_t                 i_last_section_number;
    uint8_t                 i_version_number;
    uint16_t                i_section_length;
    uint16_t                i_read_in_section;

    /* the PSI is complete */
    vlc_bool_t              b_is_complete;

    /* packet missed up ? */
    vlc_bool_t              b_trash;

    /*about sections  */
    vlc_bool_t              b_section_complete;

    /* where are we currently ? */
    byte_t                * p_current;

} psi_section_t;

/*****************************************************************************
 * decoder_descriptor_t
 *****************************************************************************/
typedef struct decoder_config_descriptor_s
{
    uint8_t                 i_objectTypeIndication;
    uint8_t                 i_streamType;
    vlc_bool_t              b_upStream;
    uint32_t                i_bufferSizeDB;
    uint32_t                i_maxBitrate;
    uint32_t                i_avgBitrate;

    int                     i_decoder_specific_info_len;
    uint8_t                 *p_decoder_specific_info;

} decoder_config_descriptor_t;

/*****************************************************************************
 * sl_descriptor_t:
 *****************************************************************************/
typedef struct sl_config_descriptor_s
{
    vlc_bool_t              b_useAccessUnitStartFlag;
    vlc_bool_t              b_useAccessUnitEndFlag;
    vlc_bool_t              b_useRandomAccessPointFlag;
    vlc_bool_t              b_useRandomAccessUnitsOnlyFlag;
    vlc_bool_t              b_usePaddingFlag;
    vlc_bool_t              b_useTimeStampsFlags;
    vlc_bool_t              b_useIdleFlag;
    vlc_bool_t              b_durationFlag;
    uint32_t                i_timeStampResolution;
    uint32_t                i_OCRResolution;
    uint8_t                 i_timeStampLength;
    uint8_t                 i_OCRLength;
    uint8_t                 i_AU_Length;
    uint8_t                 i_instantBitrateLength;
    uint8_t                 i_degradationPriorityLength;
    uint8_t                 i_AU_seqNumLength;
    uint8_t                 i_packetSeqNumLength;

    uint32_t                i_timeScale;
    uint16_t                i_accessUnitDuration;
    uint16_t                i_compositionUnitDuration;

    uint64_t                i_startDecodingTimeStamp;
    uint64_t                i_startCompositionTimeStamp;

} sl_config_descriptor_t;

/*****************************************************************************
 * es_mpeg4_descriptor_t: XXX it's not complete but should be enough
 *****************************************************************************/
typedef struct es_mpeg4_descriptor_s
{
    vlc_bool_t              b_ok;
    uint16_t                i_es_id;

    vlc_bool_t              b_streamDependenceFlag;
    vlc_bool_t              b_OCRStreamFlag;
    uint8_t                 i_streamPriority;

    char                    *psz_url;

    uint16_t                i_dependOn_es_id;
    uint16_t                i_OCR_es_id;

    decoder_config_descriptor_t    dec_descr;
    sl_config_descriptor_t         sl_descr;
} es_mpeg4_descriptor_t;

/*****************************************************************************
 * iod_descriptor_t: XXX it's not complete but should be enough
 *****************************************************************************/
typedef struct iod_descriptor_s
{
    uint8_t                i_iod_label;

    /* IOD */
    uint16_t                i_od_id;
    char                    *psz_url;

    uint8_t                 i_ODProfileLevelIndication;
    uint8_t                 i_sceneProfileLevelIndication;
    uint8_t                 i_audioProfileLevelIndication;
    uint8_t                 i_visualProfileLevelIndication;
    uint8_t                 i_graphicsProfileLevelIndication;

    es_mpeg4_descriptor_t   es_descr[255];

} iod_descriptor_t;

/*****************************************************************************
 * es_ts_data_t: extension of es_descriptor_t
 *****************************************************************************/
typedef struct es_ts_data_t
{
    vlc_bool_t              b_psi;   /* Does the stream have to be handled by
                                      *                    the PSI decoder ? */

    int                     i_psi_type;  /* There are different types of PSI */

    psi_section_t *         p_psi_section;                    /* PSI packets */

    /* Markers */
    int                     i_continuity_counter;

    /* mpeg4 in TS data specific */
    int                     b_mpeg4;
    uint16_t                i_es_id;

    /* dvb subtitles in TS data specific */
    vlc_bool_t              b_dvbsub;
    uint8_t                 i_dvbsub_es_count;
    es_descriptor_t*        p_dvbsub_es[256];

    es_mpeg4_descriptor_t   *p_es_descr;   /* es_descr of IOD */

} es_ts_data_t;

/*****************************************************************************
 * pgrm_ts_data_t: extension of pgrm_descriptor_t
 *****************************************************************************/
typedef struct pgrm_ts_data_t
{
    uint16_t                i_pcr_pid;             /* PCR ES, for TS streams */
    int                     i_pmt_version;
    /* libdvbpsi pmt decoder handle */
    void *                  p_pmt_handle;

    /* mpeg4 in TS data specific */
    vlc_bool_t              b_mpeg4;
    iod_descriptor_t        iod;

} pgrm_ts_data_t;

/*****************************************************************************
 * stream_ts_data_t: extension of stream_descriptor_t
 *****************************************************************************/
typedef struct stream_ts_data_t
{
    int                     i_pat_version; /* Current version of the PAT */
    vlc_bool_t              b_buggy_psi;
    /* libdvbpsi PMT decoder handle */
    void *                  p_pat_handle;
} stream_ts_data_t;

/*****************************************************************************
 * stream_ps_data_t: extension of stream_descriptor_t
 *****************************************************************************/
typedef struct stream_ps_data_t
{
    vlc_bool_t              b_has_PSM;                 /* very rare, in fact */

    uint8_t                 i_PSM_version;
} stream_ps_data_t;

/* PSM version is 5 bits, so -1 is not a valid value */
#define EMPTY_PSM_VERSION   -1