modules/packetizer/mjpeg.c

   1 /*****************************************************************************
   2  * mjpeg.c: MPEG packetizer
   3  *****************************************************************************
   4  * Copyright (C) 2018 VideoLabs, VLC authors and VideoLAN
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 /*****************************************************************************
  22  * Preamble
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <vlc_common.h>
  30 #include <vlc_plugin.h>
  31 #include <vlc_block.h>
  32 #include <vlc_codec.h>
  33 #include <vlc_block_helper.h>
  34 #include "packetizer_helper.h"
  35
  36 /*****************************************************************************
  37  * Local prototypes
  38  *****************************************************************************/
  39 typedef struct
  40 {
  41     packetizer_t packetizer;
  42     int i_next_block_flags;
  43     date_t date;
  44 } decoder_sys_t;
  45
  46 static const uint8_t p_mjpg_startcode[4] = { 0xFF, 0xD8, 0xFF, 0xE0 };
  47
  48 static inline const uint8_t * startcode_Find( const uint8_t *p, const uint8_t *end )
  49 {
  50     while( p + 3 < end )
  51     {
  52         p = memchr( p, 0xFF, end - p );
  53         if( !p || end - p < 4 )
  54             break;
  55         if( p[1] == 0xD8 && p[2] == 0xFF && (p[3] & 0xE0) == 0xE0 )
  56             return p;
  57         p++;
  58     }
  59     return NULL;
  60 }
  61
  62 /*****************************************************************************
  63  * Packetize:
  64  *****************************************************************************/
  65 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
  66 {
  67     decoder_sys_t *p_sys = p_dec->p_sys;
  68     return packetizer_Packetize( &p_sys->packetizer, pp_block );
  69 }
  70
  71 static void PacketizeFlush( decoder_t *p_dec )
  72 {
  73     decoder_sys_t *p_sys = p_dec->p_sys;
  74
  75     date_Set( &p_sys->date, VLC_TICK_INVALID );
  76     p_sys->i_next_block_flags = BLOCK_FLAG_DISCONTINUITY;
  77     packetizer_Flush( &p_sys->packetizer );
  78 }
  79
  80 /*****************************************************************************
  81  * Helpers:
  82  *****************************************************************************/
  83 static void PacketizeReset( void *p_private, bool b_flush )
  84 {
  85     VLC_UNUSED(b_flush);
  86     decoder_t *p_dec = p_private;
  87     decoder_sys_t *p_sys = p_dec->p_sys;
  88
  89     date_Set( &p_sys->date, VLC_TICK_INVALID );
  90     p_sys->i_next_block_flags = BLOCK_FLAG_DISCONTINUITY;
  91 }
  92
  93 static block_t *PacketizeParse( void *p_private, bool *pb_ts_used, block_t *p_block )
  94 {
  95     decoder_t *p_dec = p_private;
  96     decoder_sys_t *p_sys = p_dec->p_sys;
  97
  98     const uint8_t *p_buf = &p_block->p_buffer[2];
  99     size_t i_buf = p_block->i_buffer - 2;
 100
 101     while( i_buf > 4 && p_buf[0] == 0xFF )
 102     {
 103         size_t i_size = 2 + GetWBE( &p_buf[2] );
 104         if( i_size > i_buf )
 105             break;
 106         if( p_buf[1] == 0xC0 && i_buf > 9 )
 107         {
 108             uint16_t i_height = GetWBE( &p_buf[5] );
 109             uint16_t i_width = GetWBE( &p_buf[7] );
 110             if( i_height && i_width &&
 111                 (p_dec->fmt_out.video.i_height != i_height ||
 112                  p_dec->fmt_out.video.i_width != i_width) )
 113             {
 114                 p_dec->fmt_out.video.i_width =
 115                 p_dec->fmt_out.video.i_visible_width = i_width;
 116                 p_dec->fmt_out.video.i_height =
 117                 p_dec->fmt_out.video.i_visible_height = i_height;
 118             }
 119             break;
 120         }
 121         i_buf -= i_size;
 122         p_buf += i_size;
 123     }
 124
 125     if( p_block->i_dts == VLC_TICK_INVALID )
 126         p_block->i_dts = p_block->i_pts;
 127     else if( p_block->i_pts == VLC_TICK_INVALID )
 128         p_block->i_pts = p_block->i_dts;
 129
 130     vlc_tick_t i_prev_dts = date_Get( &p_sys->date );
 131     if( p_block->i_dts != VLC_TICK_INVALID )
 132     {
 133         date_Set( &p_sys->date, p_block->i_dts );
 134     }
 135     else if( p_dec->fmt_in.video.i_frame_rate &&
 136              p_dec->fmt_in.video.i_frame_rate_base )
 137     {
 138         date_Increment( &p_sys->date, 1 );
 139         p_block->i_dts = p_block->i_pts = date_Get( &p_sys->date );
 140     }
 141
 142     if( i_prev_dts != VLC_TICK_INVALID && p_block->i_dts != VLC_TICK_INVALID )
 143         p_block->i_length = p_block->i_dts - i_prev_dts;
 144
 145     *pb_ts_used = true;
 146
 147     p_block->i_flags = p_sys->i_next_block_flags | BLOCK_FLAG_TYPE_I;
 148     p_sys->i_next_block_flags = 0;
 149
 150     return p_block;
 151 }
 152
 153 static int PacketizeValidate( void *p_private, block_t *p_au )
 154 {
 155     VLC_UNUSED(p_private);
 156     VLC_UNUSED(p_au);
 157     return VLC_SUCCESS;
 158 }
 159
 160 /*****************************************************************************
 161  * Close:
 162  *****************************************************************************/
 163 static void Close( vlc_object_t *p_this )
 164 {
 165     decoder_t     *p_dec = (decoder_t*)p_this;
 166     decoder_sys_t *p_sys = p_dec->p_sys;
 167
 168     packetizer_Clean( &p_sys->packetizer );
 169
 170     free( p_sys );
 171 }
 172
 173 /*****************************************************************************
 174  * Open:
 175  *****************************************************************************/
 176 static int Open( vlc_object_t *p_this )
 177 {
 178     decoder_t *p_dec = (decoder_t*)p_this;
 179     decoder_sys_t *p_sys;
 180
 181     if( p_dec->fmt_in.i_codec != VLC_CODEC_MJPG )
 182         return VLC_EGENERIC;
 183
 184     p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
 185     if( !p_dec->p_sys )
 186         return VLC_ENOMEM;
 187
 188     p_sys->i_next_block_flags = 0;
 189
 190     if( p_dec->fmt_in.video.i_frame_rate &&
 191         p_dec->fmt_in.video.i_frame_rate_base )
 192     {
 193         date_Init( &p_sys->date, p_dec->fmt_in.video.i_frame_rate,
 194                    p_dec->fmt_in.video.i_frame_rate_base );
 195     }
 196     else
 197         date_Init( &p_sys->date, 30000, 1001 );
 198
 199     es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
 200
 201     /* Misc init */
 202     packetizer_Init( &p_sys->packetizer,
 203                      p_mjpg_startcode, sizeof(p_mjpg_startcode), startcode_Find,
 204                      NULL, 0, 295,
 205                      PacketizeReset, PacketizeParse, PacketizeValidate, NULL,
 206                      p_dec );
 207
 208     p_dec->pf_packetize = Packetize;
 209     p_dec->pf_flush = PacketizeFlush;
 210     p_dec->pf_get_cc = NULL;
 211
 212     return VLC_SUCCESS;
 213 }
 214
 215 /*****************************************************************************
 216  * Module descriptor
 217  *****************************************************************************/
 218
 219 vlc_module_begin ()
 220     set_category( CAT_SOUT )
 221     set_subcategory( SUBCAT_SOUT_PACKETIZER )
 222     set_description( N_("MJPEG video packetizer") )
 223     set_capability( "packetizer", 50 )
 224     set_callbacks( Open, Close )
 225 vlc_module_end ()