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) {
  47     unsigned int i = 0;
  48     unsigned char run, value;
  49
  50     while (i<bytes_per_scanline) {
  51         run = 1;
  52         value = *src++;
  53         if (value >= 0xc0) {
  54             run = value & 0x3f;
  55             value = *src++;
  56         }
  57         while (i<bytes_per_scanline && run--)
  58             dst[i++] = value;
  59     }
  60
  61     return src;
  62 }
  63
  64 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
  65     unsigned int i;
  66
  67     for (i=0; i<pallen; i++)
  68         *dst++ = bytestream_get_be24(src);
  69     memset(dst, 0, (256 - pallen) * sizeof(*dst));
  70 }
  71
  72 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
  73                             AVPacket *avpkt) {
  74     const uint8_t *buf = avpkt->data;
  75     int buf_size = avpkt->size;
  76     PCXContext * const s = avctx->priv_data;
  77     AVFrame *picture = data;
  78     AVFrame * const p = &s->picture;
  79     int xmin, ymin, xmax, ymax;
  80     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
  81                  bytes_per_scanline;
  82     uint8_t *ptr;
  83     uint8_t const *bufstart = buf;
  84
  85     if (buf[0] != 0x0a || buf[1] > 5 || buf[1] == 1 || buf[2] != 1) {
  86         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
  87         return -1;
  88     }
  89
  90     xmin = AV_RL16(buf+ 4);
  91     ymin = AV_RL16(buf+ 6);
  92     xmax = AV_RL16(buf+ 8);
  93     ymax = AV_RL16(buf+10);
  94
  95     if (xmax < xmin || ymax < ymin) {
  96         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
  97         return -1;
  98     }
  99
 100     w = xmax - xmin + 1;
 101     h = ymax - ymin + 1;
 102
 103     bits_per_pixel     = buf[3];
 104     bytes_per_line     = AV_RL16(buf+66);
 105     nplanes            = buf[65];
 106     bytes_per_scanline = nplanes * bytes_per_line;
 107
 108     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
 109         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
 110         return -1;
 111     }
 112
 113     switch ((nplanes<<8) + bits_per_pixel) {
 114         case 0x0308:
 115             avctx->pix_fmt = PIX_FMT_RGB24;
 116             break;
 117         case 0x0108:
 118         case 0x0104:
 119         case 0x0102:
 120         case 0x0101:
 121         case 0x0401:
 122         case 0x0301:
 123         case 0x0201:
 124             avctx->pix_fmt = PIX_FMT_PAL8;
 125             break;
 126         default:
 127             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
 128             return -1;
 129     }
 130
 131     buf += 128;
 132
 133     if (p->data[0])
 134         avctx->release_buffer(avctx, p);
 135
 136     if (avcodec_check_dimensions(avctx, w, h))
 137         return -1;
 138     if (w != avctx->width || h != avctx->height)
 139         avcodec_set_dimensions(avctx, w, h);
 140     if (avctx->get_buffer(avctx, p) < 0) {
 141         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 142         return -1;
 143     }
 144
 145     p->pict_type = FF_I_TYPE;
 146
 147     ptr    = p->data[0];
 148     stride = p->linesize[0];
 149
 150     if (nplanes == 3 && bits_per_pixel == 8) {
 151         uint8_t scanline[bytes_per_scanline];
 152
 153         for (y=0; y<h; y++) {
 154             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
 155
 156             for (x=0; x<w; x++) {
 157                 ptr[3*x  ] = scanline[x                    ];
 158                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
 159                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
 160             }
 161
 162             ptr += stride;
 163         }
 164
 165     } else if (nplanes == 1 && bits_per_pixel == 8) {
 166         uint8_t scanline[bytes_per_scanline];
 167         const uint8_t *palstart = bufstart + buf_size - 769;
 168
 169         for (y=0; y<h; y++, ptr+=stride) {
 170             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
 171             memcpy(ptr, scanline, w);
 172         }
 173
 174         if (buf != palstart) {
 175             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
 176             buf = palstart;
 177         }
 178         if (*buf++ != 12) {
 179             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
 180             return -1;
 181         }
 182
 183     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
 184         uint8_t scanline[bytes_per_scanline];
 185         GetBitContext s;
 186
 187         for (y=0; y<h; y++) {
 188             init_get_bits(&s, scanline, bytes_per_scanline<<3);
 189
 190             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
 191
 192             for (x=0; x<w; x++)
 193                 ptr[x] = get_bits(&s, bits_per_pixel);
 194             ptr += stride;
 195         }
 196
 197     } else {    /* planar, 4, 8 or 16 colors */
 198         uint8_t scanline[bytes_per_scanline];
 199         int i;
 200
 201         for (y=0; y<h; y++) {
 202             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
 203
 204             for (x=0; x<w; x++) {
 205                 int m = 0x80 >> (x&7), v = 0;
 206                 for (i=nplanes - 1; i>=0; i--) {
 207                     v <<= 1;
 208                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
 209                 }
 210                 ptr[x] = v;
 211             }
 212             ptr += stride;
 213         }
 214     }
 215
 216     if (nplanes == 1 && bits_per_pixel == 8) {
 217         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
 218     } else if (bits_per_pixel < 8) {
 219         const uint8_t *palette = bufstart+16;
 220         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
 221     }
 222
 223     *picture = s->picture;
 224     *data_size = sizeof(AVFrame);
 225
 226     return buf - bufstart;
 227 }
 228
 229 static av_cold int pcx_end(AVCodecContext *avctx) {
 230     PCXContext *s = avctx->priv_data;
 231
 232     if(s->picture.data[0])
 233         avctx->release_buffer(avctx, &s->picture);
 234
 235     return 0;
 236 }
 237
 238 AVCodec pcx_decoder = {
 239     "pcx",
 240     CODEC_TYPE_VIDEO,
 241     CODEC_ID_PCX,
 242     sizeof(PCXContext),
 243     pcx_init,
 244     NULL,
 245     pcx_end,
 246     pcx_decode_frame,
 247     CODEC_CAP_DR1,
 248     NULL,
 249     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
 250 };