libavcodec/pcx.c

   1 /*
   2  * PC Paintbrush PCX (.pcx) image decoder
   3  * Copyright (c) 2007, 2008 Ivo van Poorten
   4  *
   5  * This decoder does not support CGA palettes. I am unable to find samples
   6  * and Netpbm cannot generate them.
   7  *
   8  * This file is part of FFmpeg.
   9  *
  10  * FFmpeg is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * FFmpeg is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with FFmpeg; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include "avcodec.h"
  26 #include "bytestream.h"
  27 #include "get_bits.h"
  28
  29 typedef struct PCXContext {
  30     AVFrame picture;
  31 } PCXContext;
  32
  33 static av_cold int pcx_init(AVCodecContext *avctx) {
  34     PCXContext *s = avctx->priv_data;
  35
  36     avcodec_get_frame_defaults(&s->picture);
  37     avctx->coded_frame= &s->picture;
  38
  39     return 0;
  40 }
  41
  42 /**
  43  * @return advanced src pointer
  44  */
  45 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
  46                             unsigned int bytes_per_scanline, int compressed) {
  47     unsigned int i = 0;
  48     unsigned char run, value;
  49
  50     if (compressed) {
  51         while (i<bytes_per_scanline) {
  52             run = 1;
  53             value = *src++;
  54             if (value >= 0xc0) {
  55                 run = value & 0x3f;
  56                 value = *src++;
  57             }
  58             while (i<bytes_per_scanline && run--)
  59                 dst[i++] = value;
  60         }
  61     } else {
  62         memcpy(dst, src, bytes_per_scanline);
  63         src += bytes_per_scanline;
  64     }
  65
  66     return src;
  67 }
  68
  69 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
  70     unsigned int i;
  71
  72     for (i=0; i<pallen; i++)
  73         *dst++ = bytestream_get_be24(src);
  74     memset(dst, 0, (256 - pallen) * sizeof(*dst));
  75 }
  76
  77 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
  78                             AVPacket *avpkt) {
  79     const uint8_t *buf = avpkt->data;
  80     int buf_size = avpkt->size;
  81     PCXContext * const s = avctx->priv_data;
  82     AVFrame *picture = data;
  83     AVFrame * const p = &s->picture;
  84     int compressed, xmin, ymin, xmax, ymax;
  85     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
  86                  bytes_per_scanline;
  87     uint8_t *ptr;
  88     uint8_t const *bufstart = buf;
  89
  90     if (buf[0] != 0x0a || buf[1] > 5) {
  91         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
  92         return -1;
  93     }
  94
  95     compressed = buf[2];
  96     xmin = AV_RL16(buf+ 4);
  97     ymin = AV_RL16(buf+ 6);
  98     xmax = AV_RL16(buf+ 8);
  99     ymax = AV_RL16(buf+10);
 100
 101     if (xmax < xmin || ymax < ymin) {
 102         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
 103         return -1;
 104     }
 105
 106     w = xmax - xmin + 1;
 107     h = ymax - ymin + 1;
 108
 109     bits_per_pixel     = buf[3];
 110     bytes_per_line     = AV_RL16(buf+66);
 111     nplanes            = buf[65];
 112     bytes_per_scanline = nplanes * bytes_per_line;
 113
 114     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
 115         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
 116         return -1;
 117     }
 118
 119     switch ((nplanes<<8) + bits_per_pixel) {
 120         case 0x0308:
 121             avctx->pix_fmt = PIX_FMT_RGB24;
 122             break;
 123         case 0x0108:
 124         case 0x0104:
 125         case 0x0102:
 126         case 0x0101:
 127         case 0x0401:
 128         case 0x0301:
 129         case 0x0201:
 130             avctx->pix_fmt = PIX_FMT_PAL8;
 131             break;
 132         default:
 133             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
 134             return -1;
 135     }
 136
 137     buf += 128;
 138
 139     if (p->data[0])
 140         avctx->release_buffer(avctx, p);
 141
 142     if (avcodec_check_dimensions(avctx, w, h))
 143         return -1;
 144     if (w != avctx->width || h != avctx->height)
 145         avcodec_set_dimensions(avctx, w, h);
 146     if (avctx->get_buffer(avctx, p) < 0) {
 147         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 148         return -1;
 149     }
 150
 151     p->pict_type = FF_I_TYPE;
 152
 153     ptr    = p->data[0];
 154     stride = p->linesize[0];
 155
 156     if (nplanes == 3 && bits_per_pixel == 8) {
 157         uint8_t scanline[bytes_per_scanline];
 158
 159         for (y=0; y<h; y++) {
 160             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 161
 162             for (x=0; x<w; x++) {
 163                 ptr[3*x  ] = scanline[x                    ];
 164                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
 165                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
 166             }
 167
 168             ptr += stride;
 169         }
 170
 171     } else if (nplanes == 1 && bits_per_pixel == 8) {
 172         uint8_t scanline[bytes_per_scanline];
 173         const uint8_t *palstart = bufstart + buf_size - 769;
 174
 175         for (y=0; y<h; y++, ptr+=stride) {
 176             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 177             memcpy(ptr, scanline, w);
 178         }
 179
 180         if (buf != palstart) {
 181             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
 182             buf = palstart;
 183         }
 184         if (*buf++ != 12) {
 185             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
 186             return -1;
 187         }
 188
 189     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
 190         uint8_t scanline[bytes_per_scanline];
 191         GetBitContext s;
 192
 193         for (y=0; y<h; y++) {
 194             init_get_bits(&s, scanline, bytes_per_scanline<<3);
 195
 196             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 197
 198             for (x=0; x<w; x++)
 199                 ptr[x] = get_bits(&s, bits_per_pixel);
 200             ptr += stride;
 201         }
 202
 203     } else {    /* planar, 4, 8 or 16 colors */
 204         uint8_t scanline[bytes_per_scanline];
 205         int i;
 206
 207         for (y=0; y<h; y++) {
 208             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 209
 210             for (x=0; x<w; x++) {
 211                 int m = 0x80 >> (x&7), v = 0;
 212                 for (i=nplanes - 1; i>=0; i--) {
 213                     v <<= 1;
 214                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
 215                 }
 216                 ptr[x] = v;
 217             }
 218             ptr += stride;
 219         }
 220     }
 221
 222     if (nplanes == 1 && bits_per_pixel == 8) {
 223         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
 224     } else if (bits_per_pixel < 8) {
 225         const uint8_t *palette = bufstart+16;
 226         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
 227     }
 228
 229     *picture = s->picture;
 230     *data_size = sizeof(AVFrame);
 231
 232     return buf - bufstart;
 233 }
 234
 235 static av_cold int pcx_end(AVCodecContext *avctx) {
 236     PCXContext *s = avctx->priv_data;
 237
 238     if(s->picture.data[0])
 239         avctx->release_buffer(avctx, &s->picture);
 240
 241     return 0;
 242 }
 243
 244 AVCodec pcx_decoder = {
 245     "pcx",
 246     CODEC_TYPE_VIDEO,
 247     CODEC_ID_PCX,
 248     sizeof(PCXContext),
 249     pcx_init,
 250     NULL,
 251     pcx_end,
 252     pcx_decode_frame,
 253     CODEC_CAP_DR1,
 254     NULL,
 255     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
 256 };