modules/codec/png.c

   1 /*****************************************************************************
   2  * png.c: png decoder module making use of libpng.
   3  *****************************************************************************
   4  * Copyright (C) 1999-2001 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 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 General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_codec.h>
  34 #include <png.h>
  35
  36 /*****************************************************************************
  37  * decoder_sys_t : png decoder descriptor
  38  *****************************************************************************/
  39 struct decoder_sys_t
  40 {
  41     bool b_error;
  42 };
  43
  44 /*****************************************************************************
  45  * Local prototypes
  46  *****************************************************************************/
  47 static int  OpenDecoder   ( vlc_object_t * );
  48 static void CloseDecoder  ( vlc_object_t * );
  49
  50 static picture_t *DecodeBlock  ( decoder_t *, block_t ** );
  51
  52 /*****************************************************************************
  53  * Module descriptor
  54  *****************************************************************************/
  55 vlc_module_begin ()
  56     set_category( CAT_INPUT )
  57     set_subcategory( SUBCAT_INPUT_VCODEC )
  58     set_description( N_("PNG video decoder") )
  59     set_capability( "decoder", 1000 )
  60     set_callbacks( OpenDecoder, CloseDecoder )
  61     add_shortcut( "png" )
  62 vlc_module_end ()
  63
  64 /*****************************************************************************
  65  * OpenDecoder: probe the decoder and return score
  66  *****************************************************************************/
  67 static int OpenDecoder( vlc_object_t *p_this )
  68 {
  69     decoder_t *p_dec = (decoder_t*)p_this;
  70
  71     if( p_dec->fmt_in.i_codec != VLC_CODEC_PNG &&
  72         p_dec->fmt_in.i_codec != VLC_FOURCC('M','P','N','G') )
  73     {
  74         return VLC_EGENERIC;
  75     }
  76
  77     /* Allocate the memory needed to store the decoder's structure */
  78     if( ( p_dec->p_sys = malloc(sizeof(decoder_sys_t)) ) == NULL )
  79         return VLC_ENOMEM;
  80
  81     /* Set output properties */
  82     p_dec->fmt_out.i_cat = VIDEO_ES;
  83     p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;
  84
  85     /* Set callbacks */
  86     p_dec->pf_decode_video = DecodeBlock;
  87
  88     return VLC_SUCCESS;
  89 }
  90
  91 static void user_read( png_structp p_png, png_bytep data, png_size_t i_length )
  92 {
  93     block_t *p_block = (block_t *)png_get_io_ptr( p_png );
  94     png_size_t i_read = __MIN( p_block->i_buffer, i_length );
  95     memcpy( data, p_block->p_buffer, i_length );
  96     p_block->p_buffer += i_length;
  97     p_block->i_buffer -= i_length;
  98
  99     if( i_length != i_read ) png_error( p_png, "not enough data" );
 100 }
 101
 102 static void user_error( png_structp p_png, png_const_charp error_msg )
 103 {
 104     decoder_t *p_dec = (decoder_t *)png_get_error_ptr( p_png );
 105     p_dec->p_sys->b_error = true;
 106     msg_Err( p_dec, "%s", error_msg );
 107 }
 108
 109 static void user_warning( png_structp p_png, png_const_charp warning_msg )
 110 {
 111     decoder_t *p_dec = (decoder_t *)png_get_error_ptr( p_png );
 112     msg_Warn( p_dec, "%s", warning_msg );
 113 }
 114
 115 /****************************************************************************
 116  * DecodeBlock: the whole thing
 117  ****************************************************************************
 118  * This function must be fed with a complete compressed frame.
 119  ****************************************************************************/
 120 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 121 {
 122     decoder_sys_t *p_sys = p_dec->p_sys;
 123     block_t *p_block;
 124     picture_t *p_pic = 0;
 125
 126     png_uint_32 i_width, i_height;
 127     int i_color_type, i_interlace_type, i_compression_type, i_filter_type;
 128     int i_bit_depth, i;
 129
 130     png_structp p_png;
 131     png_infop p_info, p_end_info;
 132     png_bytep *p_row_pointers = NULL;
 133
 134     if( !pp_block || !*pp_block ) return NULL;
 135
 136     p_block = *pp_block;
 137     p_sys->b_error = false;
 138
 139     if( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
 140     {
 141         block_Release( p_block ); *pp_block = NULL;
 142         return NULL;
 143     }
 144
 145     p_png = png_create_read_struct( PNG_LIBPNG_VER_STRING, 0, 0, 0 );
 146     if( p_png == NULL )
 147     {
 148         block_Release( p_block ); *pp_block = NULL;
 149         return NULL;
 150     }
 151
 152     p_info = png_create_info_struct( p_png );
 153     if( p_info == NULL )
 154     {
 155         png_destroy_read_struct( &p_png, NULL, NULL );
 156         block_Release( p_block ); *pp_block = NULL;
 157         return NULL;
 158     }
 159
 160     p_end_info = png_create_info_struct( p_png );
 161     if( p_end_info == NULL )
 162     {
 163         png_destroy_read_struct( &p_png, &p_info, NULL );
 164         block_Release( p_block ); *pp_block = NULL;
 165         return NULL;
 166     }
 167
 168     /* libpng longjmp's there in case of error */
 169     if( setjmp( png_jmpbuf( p_png ) ) )
 170         goto error;
 171
 172     png_set_read_fn( p_png, (void *)p_block, user_read );
 173     png_set_error_fn( p_png, (void *)p_dec, user_error, user_warning );
 174
 175     png_read_info( p_png, p_info );
 176     if( p_sys->b_error ) goto error;
 177
 178     png_get_IHDR( p_png, p_info, &i_width, &i_height,
 179                   &i_bit_depth, &i_color_type, &i_interlace_type,
 180                   &i_compression_type, &i_filter_type);
 181     if( p_sys->b_error ) goto error;
 182
 183     /* Set output properties */
 184     p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;
 185     p_dec->fmt_out.video.i_width = i_width;
 186     p_dec->fmt_out.video.i_height = i_height;
 187     p_dec->fmt_out.video.i_sar_num = 1;
 188     p_dec->fmt_out.video.i_sar_den = 1;
 189     p_dec->fmt_out.video.i_rmask = 0x000000ff;
 190     p_dec->fmt_out.video.i_gmask = 0x0000ff00;
 191     p_dec->fmt_out.video.i_bmask = 0x00ff0000;
 192
 193     if( i_color_type == PNG_COLOR_TYPE_PALETTE )
 194         png_set_palette_to_rgb( p_png );
 195
 196     if( i_color_type == PNG_COLOR_TYPE_GRAY ||
 197         i_color_type == PNG_COLOR_TYPE_GRAY_ALPHA )
 198           png_set_gray_to_rgb( p_png );
 199
 200     /* Strip to 8 bits per channel */
 201     if( i_bit_depth == 16 ) png_set_strip_16( p_png );
 202
 203     if( png_get_valid( p_png, p_info, PNG_INFO_tRNS ) )
 204     {
 205         png_set_tRNS_to_alpha( p_png );
 206     }
 207     else if( !(i_color_type & PNG_COLOR_MASK_ALPHA) )
 208     {
 209         p_dec->fmt_out.i_codec = VLC_CODEC_RGB24;
 210     }
 211
 212     /* Get a new picture */
 213     p_pic = decoder_NewPicture( p_dec );
 214     if( !p_pic ) goto error;
 215
 216     /* Decode picture */
 217     p_row_pointers = malloc( sizeof(png_bytep) * i_height );
 218     if( !p_row_pointers )
 219         goto error;
 220     for( i = 0; i < (int)i_height; i++ )
 221         p_row_pointers[i] = p_pic->p->p_pixels + p_pic->p->i_pitch * i;
 222
 223     png_read_image( p_png, p_row_pointers );
 224     if( p_sys->b_error ) goto error;
 225     png_read_end( p_png, p_end_info );
 226     if( p_sys->b_error ) goto error;
 227
 228     png_destroy_read_struct( &p_png, &p_info, &p_end_info );
 229     free( p_row_pointers );
 230
 231     p_pic->date = p_block->i_pts > VLC_TS_INVALID ? p_block->i_pts : p_block->i_dts;
 232
 233     block_Release( p_block ); *pp_block = NULL;
 234     return p_pic;
 235
 236  error:
 237
 238     free( p_row_pointers );
 239     png_destroy_read_struct( &p_png, &p_info, &p_end_info );
 240     block_Release( p_block ); *pp_block = NULL;
 241     return NULL;
 242 }
 243
 244 /*****************************************************************************
 245  * CloseDecoder: png decoder destruction
 246  *****************************************************************************/
 247 static void CloseDecoder( vlc_object_t *p_this )
 248 {
 249     decoder_t *p_dec = (decoder_t *)p_this;
 250     decoder_sys_t *p_sys = p_dec->p_sys;
 251
 252     free( p_sys );
 253 }