modules/packetizer/packetizer_helper.h

   1 /*****************************************************************************
   2  * packetizer_helper.h: Packetizer helpers
   3  *****************************************************************************
   4  * Copyright (C) 2009 Laurent Aimar
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef VLC_PACKETIZER_HELPER_H_
  25 #define VLC_PACKETIZER_HELPER_H_
  26
  27 #include <vlc_block.h>
  28
  29 enum
  30 {
  31     STATE_NOSYNC,
  32     STATE_SYNC,
  33     STATE_HEADER,
  34     STATE_NEXT_SYNC,
  35     STATE_GET_DATA,
  36     STATE_SEND_DATA
  37 };
  38
  39 typedef void (*packetizer_reset_t)( void *p_private, bool b_broken );
  40 typedef block_t *(*packetizer_parse_t)( void *p_private, bool *pb_ts_used, block_t * );
  41 typedef int (*packetizer_validate_t)( void *p_private, block_t * );
  42
  43 typedef struct
  44 {
  45     int i_state;
  46     block_bytestream_t bytestream;
  47     size_t i_offset;
  48
  49     int i_startcode;
  50     const uint8_t *p_startcode;
  51     block_startcode_helper_t pf_startcode_helper;
  52
  53     int i_au_prepend;
  54     const uint8_t *p_au_prepend;
  55
  56     unsigned i_au_min_size;
  57
  58     void *p_private;
  59     packetizer_reset_t    pf_reset;
  60     packetizer_parse_t    pf_parse;
  61     packetizer_validate_t pf_validate;
  62
  63 } packetizer_t;
  64
  65 static inline void packetizer_Init( packetizer_t *p_pack,
  66                                     const uint8_t *p_startcode, int i_startcode,
  67                                     block_startcode_helper_t pf_start_helper,
  68                                     const uint8_t *p_au_prepend, int i_au_prepend,
  69                                     unsigned i_au_min_size,
  70                                     packetizer_reset_t pf_reset,
  71                                     packetizer_parse_t pf_parse,
  72                                     packetizer_validate_t pf_validate,
  73                                     void *p_private )
  74 {
  75     p_pack->i_state = STATE_NOSYNC;
  76     block_BytestreamInit( &p_pack->bytestream );
  77     p_pack->i_offset = 0;
  78
  79     p_pack->i_au_prepend = i_au_prepend;
  80     p_pack->p_au_prepend = p_au_prepend;
  81     p_pack->i_au_min_size = i_au_min_size;
  82
  83     p_pack->i_startcode = i_startcode;
  84     p_pack->p_startcode = p_startcode;
  85     p_pack->pf_startcode_helper = pf_start_helper;
  86     p_pack->pf_reset = pf_reset;
  87     p_pack->pf_parse = pf_parse;
  88     p_pack->pf_validate = pf_validate;
  89     p_pack->p_private = p_private;
  90 }
  91
  92 static inline void packetizer_Clean( packetizer_t *p_pack )
  93 {
  94     block_BytestreamRelease( &p_pack->bytestream );
  95 }
  96
  97 static inline void packetizer_Flush( packetizer_t *p_pack )
  98 {
  99     p_pack->i_state = STATE_NOSYNC;
 100     block_BytestreamEmpty( &p_pack->bytestream );
 101     p_pack->i_offset = 0;
 102     p_pack->pf_reset( p_pack->p_private, true );
 103 }
 104
 105 static inline block_t *packetizer_Packetize( packetizer_t *p_pack, block_t **pp_block )
 106 {
 107     block_t *p_block = ( pp_block ) ? *pp_block : NULL;
 108
 109     if( p_block == NULL && p_pack->bytestream.p_block == NULL )
 110         return NULL; /* nothing to do */
 111
 112     if( p_block && unlikely( p_block->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) ) )
 113     {
 114         block_t *p_drained = packetizer_Packetize( p_pack, NULL );
 115         if( p_drained )
 116             return p_drained;
 117
 118         const bool b_broken = !!( p_block->i_flags&BLOCK_FLAG_CORRUPTED );
 119         p_pack->i_state = STATE_NOSYNC;
 120         block_BytestreamEmpty( &p_pack->bytestream );
 121         p_pack->i_offset = 0;
 122         p_pack->pf_reset( p_pack->p_private, b_broken );
 123         if( b_broken )
 124         {
 125             block_Release( p_block );
 126             return NULL;
 127         }
 128     }
 129
 130     if( p_block )
 131         block_BytestreamPush( &p_pack->bytestream, p_block );
 132
 133     for( ;; )
 134     {
 135         bool b_used_ts;
 136         block_t *p_pic;
 137
 138         switch( p_pack->i_state )
 139         {
 140         case STATE_NOSYNC:
 141             /* Find a startcode */
 142             if( !block_FindStartcodeFromOffset( &p_pack->bytestream, &p_pack->i_offset,
 143                                                 p_pack->p_startcode, p_pack->i_startcode,
 144                                                 p_pack->pf_startcode_helper, NULL ) )
 145                 p_pack->i_state = STATE_NEXT_SYNC;
 146
 147             if( p_pack->i_offset )
 148             {
 149                 block_SkipBytes( &p_pack->bytestream, p_pack->i_offset );
 150                 p_pack->i_offset = 0;
 151                 block_BytestreamFlush( &p_pack->bytestream );
 152             }
 153
 154             if( p_pack->i_state != STATE_NEXT_SYNC )
 155                 return NULL; /* Need more data */
 156
 157             p_pack->i_offset = 1; /* To find next startcode */
 158             /* fallthrough */
 159
 160         case STATE_NEXT_SYNC:
 161             /* Find the next startcode */
 162             if( block_FindStartcodeFromOffset( &p_pack->bytestream, &p_pack->i_offset,
 163                                                p_pack->p_startcode, p_pack->i_startcode,
 164                                                p_pack->pf_startcode_helper, NULL ) )
 165             {
 166                 if( pp_block /* not flushing */ || !p_pack->bytestream.p_chain )
 167                     return NULL; /* Need more data */
 168
 169                 /* When flusing and we don't find a startcode, suppose that
 170                  * the data extend up to the end */
 171                 block_ChainProperties( p_pack->bytestream.p_chain,
 172                                        NULL, &p_pack->i_offset, NULL );
 173                 p_pack->i_offset -= p_pack->bytestream.i_block_offset;
 174
 175                 if( p_pack->i_offset <= (size_t)p_pack->i_startcode )
 176                     return NULL;
 177             }
 178
 179             block_BytestreamFlush( &p_pack->bytestream );
 180
 181             /* Get the new fragment and set the pts/dts */
 182             block_t *p_block_bytestream = p_pack->bytestream.p_block;
 183
 184             p_pic = block_Alloc( p_pack->i_offset + p_pack->i_au_prepend );
 185             p_pic->i_pts = p_block_bytestream->i_pts;
 186             p_pic->i_dts = p_block_bytestream->i_dts;
 187
 188             block_GetBytes( &p_pack->bytestream, &p_pic->p_buffer[p_pack->i_au_prepend],
 189                             p_pic->i_buffer - p_pack->i_au_prepend );
 190             if( p_pack->i_au_prepend > 0 )
 191                 memcpy( p_pic->p_buffer, p_pack->p_au_prepend, p_pack->i_au_prepend );
 192
 193             p_pack->i_offset = 0;
 194
 195             /* Parse the NAL */
 196             if( p_pic->i_buffer < p_pack->i_au_min_size )
 197             {
 198                 block_Release( p_pic );
 199                 p_pic = NULL;
 200             }
 201             else
 202             {
 203                 p_pic = p_pack->pf_parse( p_pack->p_private, &b_used_ts, p_pic );
 204                 if( b_used_ts )
 205                 {
 206                     p_block_bytestream->i_dts = VLC_TS_INVALID;
 207                     p_block_bytestream->i_pts = VLC_TS_INVALID;
 208                 }
 209             }
 210
 211             if( !p_pic )
 212             {
 213                 p_pack->i_state = STATE_NOSYNC;
 214                 break;
 215             }
 216             if( p_pack->pf_validate( p_pack->p_private, p_pic ) )
 217             {
 218                 p_pack->i_state = STATE_NOSYNC;
 219                 block_Release( p_pic );
 220                 break;
 221             }
 222
 223             /* So p_block doesn't get re-added several times */
 224             if( pp_block )
 225                 *pp_block = block_BytestreamPop( &p_pack->bytestream );
 226
 227             p_pack->i_state = STATE_NOSYNC;
 228
 229             return p_pic;
 230         }
 231     }
 232 }
 233
 234 static inline void packetizer_Header( packetizer_t *p_pack,
 235                                       const uint8_t *p_header, int i_header )
 236 {
 237     block_t *p_init = block_Alloc( i_header );
 238     if( !p_init )
 239         return;
 240
 241     memcpy( p_init->p_buffer, p_header, i_header );
 242
 243     block_t *p_pic;
 244     while( ( p_pic = packetizer_Packetize( p_pack, &p_init ) ) )
 245         block_Release( p_pic ); /* Should not happen (only sequence header) */
 246     while( ( p_pic = packetizer_Packetize( p_pack, NULL ) ) )
 247         block_Release( p_pic );
 248
 249     p_pack->i_state = STATE_NOSYNC;
 250     block_BytestreamEmpty( &p_pack->bytestream );
 251     p_pack->i_offset = 0;
 252 }
 253
 254 #endif
 255