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libavcodec/pcx.c

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00001 /*
00002  * PC Paintbrush PCX (.pcx) image decoder
00003  * Copyright (c) 2007, 2008 Ivo van Poorten
00004  *
00005  * This decoder does not support CGA palettes. I am unable to find samples
00006  * and Netpbm cannot generate them.
00007  *
00008  * This file is part of FFmpeg.
00009  *
00010  * FFmpeg is free software; you can redistribute it and/or
00011  * modify it under the terms of the GNU Lesser General Public
00012  * License as published by the Free Software Foundation; either
00013  * version 2.1 of the License, or (at your option) any later version.
00014  *
00015  * FFmpeg is distributed in the hope that it will be useful,
00016  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018  * Lesser General Public License for more details.
00019  *
00020  * You should have received a copy of the GNU Lesser General Public
00021  * License along with FFmpeg; if not, write to the Free Software
00022  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00023  */
00024 
00025 #include "avcodec.h"
00026 #include "bytestream.h"
00027 #include "bitstream.h"
00028 
00029 typedef struct PCXContext {
00030     AVFrame picture;
00031 } PCXContext;
00032 
00033 static av_cold int pcx_init(AVCodecContext *avctx) {
00034     PCXContext *s = avctx->priv_data;
00035 
00036     avcodec_get_frame_defaults(&s->picture);
00037     avctx->coded_frame= &s->picture;
00038 
00039     return 0;
00040 }
00041 
00045 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
00046                             unsigned int bytes_per_scanline) {
00047     unsigned int i = 0;
00048     unsigned char run, value;
00049 
00050     while (i<bytes_per_scanline) {
00051         run = 1;
00052         value = *src++;
00053         if (value >= 0xc0) {
00054             run = value & 0x3f;
00055             value = *src++;
00056         }
00057         while (i<bytes_per_scanline && run--)
00058             dst[i++] = value;
00059     }
00060 
00061     return src;
00062 }
00063 
00064 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
00065     unsigned int i;
00066 
00067     for (i=0; i<pallen; i++)
00068         *dst++ = bytestream_get_be24(src);
00069     memset(dst, 0, (256 - pallen) * sizeof(*dst));
00070 }
00071 
00072 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
00073                             const uint8_t *buf, int buf_size) {
00074     PCXContext * const s = avctx->priv_data;
00075     AVFrame *picture = data;
00076     AVFrame * const p = &s->picture;
00077     int xmin, ymin, xmax, ymax;
00078     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
00079                  bytes_per_scanline;
00080     uint8_t *ptr;
00081     uint8_t const *bufstart = buf;
00082 
00083     if (buf[0] != 0x0a || buf[1] > 5 || buf[1] == 1 || buf[2] != 1) {
00084         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
00085         return -1;
00086     }
00087 
00088     xmin = AV_RL16(buf+ 4);
00089     ymin = AV_RL16(buf+ 6);
00090     xmax = AV_RL16(buf+ 8);
00091     ymax = AV_RL16(buf+10);
00092 
00093     if (xmax < xmin || ymax < ymin) {
00094         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
00095         return -1;
00096     }
00097 
00098     w = xmax - xmin + 1;
00099     h = ymax - ymin + 1;
00100 
00101     bits_per_pixel     = buf[3];
00102     bytes_per_line     = AV_RL16(buf+66);
00103     nplanes            = buf[65];
00104     bytes_per_scanline = nplanes * bytes_per_line;
00105 
00106     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
00107         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
00108         return -1;
00109     }
00110 
00111     switch ((nplanes<<8) + bits_per_pixel) {
00112         case 0x0308:
00113             avctx->pix_fmt = PIX_FMT_RGB24;
00114             break;
00115         case 0x0108:
00116         case 0x0104:
00117         case 0x0102:
00118         case 0x0101:
00119         case 0x0401:
00120         case 0x0301:
00121         case 0x0201:
00122             avctx->pix_fmt = PIX_FMT_PAL8;
00123             break;
00124         default:
00125             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
00126             return -1;
00127     }
00128 
00129     buf += 128;
00130 
00131     if (p->data[0])
00132         avctx->release_buffer(avctx, p);
00133 
00134     if (avcodec_check_dimensions(avctx, w, h))
00135         return -1;
00136     if (w != avctx->width || h != avctx->height)
00137         avcodec_set_dimensions(avctx, w, h);
00138     if (avctx->get_buffer(avctx, p) < 0) {
00139         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00140         return -1;
00141     }
00142 
00143     p->pict_type = FF_I_TYPE;
00144 
00145     ptr    = p->data[0];
00146     stride = p->linesize[0];
00147 
00148     if (nplanes == 3 && bits_per_pixel == 8) {
00149         uint8_t scanline[bytes_per_scanline];
00150 
00151         for (y=0; y<h; y++) {
00152             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
00153 
00154             for (x=0; x<w; x++) {
00155                 ptr[3*x  ] = scanline[x                    ];
00156                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
00157                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
00158             }
00159 
00160             ptr += stride;
00161         }
00162 
00163     } else if (nplanes == 1 && bits_per_pixel == 8) {
00164         uint8_t scanline[bytes_per_scanline];
00165         const uint8_t *palstart = bufstart + buf_size - 769;
00166 
00167         for (y=0; y<h; y++, ptr+=stride) {
00168             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
00169             memcpy(ptr, scanline, w);
00170         }
00171 
00172         if (buf != palstart) {
00173             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
00174             buf = palstart;
00175         }
00176         if (*buf++ != 12) {
00177             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
00178             return -1;
00179         }
00180 
00181     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
00182         uint8_t scanline[bytes_per_scanline];
00183         GetBitContext s;
00184 
00185         for (y=0; y<h; y++) {
00186             init_get_bits(&s, scanline, bytes_per_scanline<<3);
00187 
00188             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
00189 
00190             for (x=0; x<w; x++)
00191                 ptr[x] = get_bits(&s, bits_per_pixel);
00192             ptr += stride;
00193         }
00194 
00195     } else {    /* planar, 4, 8 or 16 colors */
00196         uint8_t scanline[bytes_per_scanline];
00197         int i;
00198 
00199         for (y=0; y<h; y++) {
00200             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline);
00201 
00202             for (x=0; x<w; x++) {
00203                 int m = 0x80 >> (x&7), v = 0;
00204                 for (i=nplanes - 1; i>=0; i--) {
00205                     v <<= 1;
00206                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
00207                 }
00208                 ptr[x] = v;
00209             }
00210             ptr += stride;
00211         }
00212     }
00213 
00214     if (nplanes == 1 && bits_per_pixel == 8) {
00215         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
00216     } else if (bits_per_pixel < 8) {
00217         const uint8_t *palette = bufstart+16;
00218         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
00219     }
00220 
00221     *picture = s->picture;
00222     *data_size = sizeof(AVFrame);
00223 
00224     return buf - bufstart;
00225 }
00226 
00227 static av_cold int pcx_end(AVCodecContext *avctx) {
00228     PCXContext *s = avctx->priv_data;
00229 
00230     if(s->picture.data[0])
00231         avctx->release_buffer(avctx, &s->picture);
00232 
00233     return 0;
00234 }
00235 
00236 AVCodec pcx_decoder = {
00237     "pcx",
00238     CODEC_TYPE_VIDEO,
00239     CODEC_ID_PCX,
00240     sizeof(PCXContext),
00241     pcx_init,
00242     NULL,
00243     pcx_end,
00244     pcx_decode_frame,
00245     0,
00246     NULL,
00247     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
00248 };

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