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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 "get_bits.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, int compressed) {
00047     unsigned int i = 0;
00048     unsigned char run, value;
00049 
00050     if (compressed) {
00051         while (i<bytes_per_scanline) {
00052             run = 1;
00053             value = *src++;
00054             if (value >= 0xc0) {
00055                 run = value & 0x3f;
00056                 value = *src++;
00057             }
00058             while (i<bytes_per_scanline && run--)
00059                 dst[i++] = value;
00060         }
00061     } else {
00062         memcpy(dst, src, bytes_per_scanline);
00063         src += bytes_per_scanline;
00064     }
00065 
00066     return src;
00067 }
00068 
00069 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
00070     unsigned int i;
00071 
00072     for (i=0; i<pallen; i++)
00073         *dst++ = bytestream_get_be24(src);
00074     if (pallen < 256)
00075         memset(dst, 0, (256 - pallen) * sizeof(*dst));
00076 }
00077 
00078 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
00079                             AVPacket *avpkt) {
00080     const uint8_t *buf = avpkt->data;
00081     int buf_size = avpkt->size;
00082     PCXContext * const s = avctx->priv_data;
00083     AVFrame *picture = data;
00084     AVFrame * const p = &s->picture;
00085     int compressed, xmin, ymin, xmax, ymax;
00086     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
00087                  bytes_per_scanline;
00088     uint8_t *ptr;
00089     uint8_t const *bufstart = buf;
00090 
00091     if (buf[0] != 0x0a || buf[1] > 5) {
00092         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
00093         return -1;
00094     }
00095 
00096     compressed = buf[2];
00097     xmin = AV_RL16(buf+ 4);
00098     ymin = AV_RL16(buf+ 6);
00099     xmax = AV_RL16(buf+ 8);
00100     ymax = AV_RL16(buf+10);
00101 
00102     if (xmax < xmin || ymax < ymin) {
00103         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
00104         return -1;
00105     }
00106 
00107     w = xmax - xmin + 1;
00108     h = ymax - ymin + 1;
00109 
00110     bits_per_pixel     = buf[3];
00111     bytes_per_line     = AV_RL16(buf+66);
00112     nplanes            = buf[65];
00113     bytes_per_scanline = nplanes * bytes_per_line;
00114 
00115     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
00116         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
00117         return -1;
00118     }
00119 
00120     switch ((nplanes<<8) + bits_per_pixel) {
00121         case 0x0308:
00122             avctx->pix_fmt = PIX_FMT_RGB24;
00123             break;
00124         case 0x0108:
00125         case 0x0104:
00126         case 0x0102:
00127         case 0x0101:
00128         case 0x0401:
00129         case 0x0301:
00130         case 0x0201:
00131             avctx->pix_fmt = PIX_FMT_PAL8;
00132             break;
00133         default:
00134             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
00135             return -1;
00136     }
00137 
00138     buf += 128;
00139 
00140     if (p->data[0])
00141         avctx->release_buffer(avctx, p);
00142 
00143     if (avcodec_check_dimensions(avctx, w, h))
00144         return -1;
00145     if (w != avctx->width || h != avctx->height)
00146         avcodec_set_dimensions(avctx, w, h);
00147     if (avctx->get_buffer(avctx, p) < 0) {
00148         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00149         return -1;
00150     }
00151 
00152     p->pict_type = FF_I_TYPE;
00153 
00154     ptr    = p->data[0];
00155     stride = p->linesize[0];
00156 
00157     if (nplanes == 3 && bits_per_pixel == 8) {
00158         uint8_t scanline[bytes_per_scanline];
00159 
00160         for (y=0; y<h; y++) {
00161             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00162 
00163             for (x=0; x<w; x++) {
00164                 ptr[3*x  ] = scanline[x                    ];
00165                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
00166                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
00167             }
00168 
00169             ptr += stride;
00170         }
00171 
00172     } else if (nplanes == 1 && bits_per_pixel == 8) {
00173         uint8_t scanline[bytes_per_scanline];
00174         const uint8_t *palstart = bufstart + buf_size - 769;
00175 
00176         for (y=0; y<h; y++, ptr+=stride) {
00177             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00178             memcpy(ptr, scanline, w);
00179         }
00180 
00181         if (buf != palstart) {
00182             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
00183             buf = palstart;
00184         }
00185         if (*buf++ != 12) {
00186             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
00187             return -1;
00188         }
00189 
00190     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
00191         uint8_t scanline[bytes_per_scanline];
00192         GetBitContext s;
00193 
00194         for (y=0; y<h; y++) {
00195             init_get_bits(&s, scanline, bytes_per_scanline<<3);
00196 
00197             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00198 
00199             for (x=0; x<w; x++)
00200                 ptr[x] = get_bits(&s, bits_per_pixel);
00201             ptr += stride;
00202         }
00203 
00204     } else {    /* planar, 4, 8 or 16 colors */
00205         uint8_t scanline[bytes_per_scanline];
00206         int i;
00207 
00208         for (y=0; y<h; y++) {
00209             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00210 
00211             for (x=0; x<w; x++) {
00212                 int m = 0x80 >> (x&7), v = 0;
00213                 for (i=nplanes - 1; i>=0; i--) {
00214                     v <<= 1;
00215                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
00216                 }
00217                 ptr[x] = v;
00218             }
00219             ptr += stride;
00220         }
00221     }
00222 
00223     if (nplanes == 1 && bits_per_pixel == 8) {
00224         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
00225     } else if (bits_per_pixel < 8) {
00226         const uint8_t *palette = bufstart+16;
00227         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
00228     }
00229 
00230     *picture = s->picture;
00231     *data_size = sizeof(AVFrame);
00232 
00233     return buf - bufstart;
00234 }
00235 
00236 static av_cold int pcx_end(AVCodecContext *avctx) {
00237     PCXContext *s = avctx->priv_data;
00238 
00239     if(s->picture.data[0])
00240         avctx->release_buffer(avctx, &s->picture);
00241 
00242     return 0;
00243 }
00244 
00245 AVCodec pcx_decoder = {
00246     "pcx",
00247     AVMEDIA_TYPE_VIDEO,
00248     CODEC_ID_PCX,
00249     sizeof(PCXContext),
00250     pcx_init,
00251     NULL,
00252     pcx_end,
00253     pcx_decode_frame,
00254     CODEC_CAP_DR1,
00255     NULL,
00256     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
00257 };

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