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 "libavutil/imgutils.h"
00026 #include "avcodec.h"
00027 #include "bytestream.h"
00028 #include "get_bits.h"
00029 
00030 typedef struct PCXContext {
00031     AVFrame picture;
00032 } PCXContext;
00033 
00034 static av_cold int pcx_init(AVCodecContext *avctx) {
00035     PCXContext *s = avctx->priv_data;
00036 
00037     avcodec_get_frame_defaults(&s->picture);
00038     avctx->coded_frame= &s->picture;
00039 
00040     return 0;
00041 }
00042 
00046 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
00047                             unsigned int bytes_per_scanline, int compressed) {
00048     unsigned int i = 0;
00049     unsigned char run, value;
00050 
00051     if (compressed) {
00052         while (i<bytes_per_scanline) {
00053             run = 1;
00054             value = *src++;
00055             if (value >= 0xc0) {
00056                 run = value & 0x3f;
00057                 value = *src++;
00058             }
00059             while (i<bytes_per_scanline && run--)
00060                 dst[i++] = value;
00061         }
00062     } else {
00063         memcpy(dst, src, bytes_per_scanline);
00064         src += bytes_per_scanline;
00065     }
00066 
00067     return src;
00068 }
00069 
00070 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
00071     unsigned int i;
00072 
00073     for (i=0; i<pallen; i++)
00074         *dst++ = 0xFF000000 | bytestream_get_be24(src);
00075     if (pallen < 256)
00076         memset(dst, 0, (256 - pallen) * sizeof(*dst));
00077 }
00078 
00079 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
00080                             AVPacket *avpkt) {
00081     const uint8_t *buf = avpkt->data;
00082     int buf_size = avpkt->size;
00083     PCXContext * const s = avctx->priv_data;
00084     AVFrame *picture = data;
00085     AVFrame * const p = &s->picture;
00086     int compressed, xmin, ymin, xmax, ymax;
00087     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
00088                  bytes_per_scanline;
00089     uint8_t *ptr;
00090     uint8_t const *bufstart = buf;
00091     uint8_t *scanline;
00092     int ret = -1;
00093 
00094     if (buf[0] != 0x0a || buf[1] > 5) {
00095         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
00096         return -1;
00097     }
00098 
00099     compressed = buf[2];
00100     xmin = AV_RL16(buf+ 4);
00101     ymin = AV_RL16(buf+ 6);
00102     xmax = AV_RL16(buf+ 8);
00103     ymax = AV_RL16(buf+10);
00104 
00105     if (xmax < xmin || ymax < ymin) {
00106         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
00107         return -1;
00108     }
00109 
00110     w = xmax - xmin + 1;
00111     h = ymax - ymin + 1;
00112 
00113     bits_per_pixel     = buf[3];
00114     bytes_per_line     = AV_RL16(buf+66);
00115     nplanes            = buf[65];
00116     bytes_per_scanline = nplanes * bytes_per_line;
00117 
00118     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
00119         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
00120         return -1;
00121     }
00122 
00123     switch ((nplanes<<8) + bits_per_pixel) {
00124         case 0x0308:
00125             avctx->pix_fmt = PIX_FMT_RGB24;
00126             break;
00127         case 0x0108:
00128         case 0x0104:
00129         case 0x0102:
00130         case 0x0101:
00131         case 0x0401:
00132         case 0x0301:
00133         case 0x0201:
00134             avctx->pix_fmt = PIX_FMT_PAL8;
00135             break;
00136         default:
00137             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
00138             return -1;
00139     }
00140 
00141     buf += 128;
00142 
00143     if (p->data[0])
00144         avctx->release_buffer(avctx, p);
00145 
00146     if (av_image_check_size(w, h, 0, avctx))
00147         return -1;
00148     if (w != avctx->width || h != avctx->height)
00149         avcodec_set_dimensions(avctx, w, h);
00150     if (avctx->get_buffer(avctx, p) < 0) {
00151         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00152         return -1;
00153     }
00154 
00155     p->pict_type = AV_PICTURE_TYPE_I;
00156 
00157     ptr    = p->data[0];
00158     stride = p->linesize[0];
00159 
00160     scanline = av_malloc(bytes_per_scanline);
00161     if (!scanline)
00162         return AVERROR(ENOMEM);
00163 
00164     if (nplanes == 3 && bits_per_pixel == 8) {
00165         for (y=0; y<h; y++) {
00166             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00167 
00168             for (x=0; x<w; x++) {
00169                 ptr[3*x  ] = scanline[x                    ];
00170                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
00171                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
00172             }
00173 
00174             ptr += stride;
00175         }
00176 
00177     } else if (nplanes == 1 && bits_per_pixel == 8) {
00178         const uint8_t *palstart = bufstart + buf_size - 769;
00179 
00180         for (y=0; y<h; y++, ptr+=stride) {
00181             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00182             memcpy(ptr, scanline, w);
00183         }
00184 
00185         if (buf != palstart) {
00186             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
00187             buf = palstart;
00188         }
00189         if (*buf++ != 12) {
00190             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
00191             goto end;
00192         }
00193 
00194     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
00195         GetBitContext s;
00196 
00197         for (y=0; y<h; y++) {
00198             init_get_bits(&s, scanline, bytes_per_scanline<<3);
00199 
00200             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00201 
00202             for (x=0; x<w; x++)
00203                 ptr[x] = get_bits(&s, bits_per_pixel);
00204             ptr += stride;
00205         }
00206 
00207     } else {    /* planar, 4, 8 or 16 colors */
00208         int i;
00209 
00210         for (y=0; y<h; y++) {
00211             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
00212 
00213             for (x=0; x<w; x++) {
00214                 int m = 0x80 >> (x&7), v = 0;
00215                 for (i=nplanes - 1; i>=0; i--) {
00216                     v <<= 1;
00217                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
00218                 }
00219                 ptr[x] = v;
00220             }
00221             ptr += stride;
00222         }
00223     }
00224 
00225     if (nplanes == 1 && bits_per_pixel == 8) {
00226         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
00227     } else if (bits_per_pixel * nplanes == 1) {
00228         AV_WN32A(p->data[1]  , 0xFF000000);
00229         AV_WN32A(p->data[1]+4, 0xFFFFFFFF);
00230     } else if (bits_per_pixel < 8) {
00231         const uint8_t *palette = bufstart+16;
00232         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
00233     }
00234 
00235     *picture = s->picture;
00236     *data_size = sizeof(AVFrame);
00237 
00238     ret = buf - bufstart;
00239 end:
00240     av_free(scanline);
00241     return ret;
00242 }
00243 
00244 static av_cold int pcx_end(AVCodecContext *avctx) {
00245     PCXContext *s = avctx->priv_data;
00246 
00247     if(s->picture.data[0])
00248         avctx->release_buffer(avctx, &s->picture);
00249 
00250     return 0;
00251 }
00252 
00253 AVCodec ff_pcx_decoder = {
00254     .name           = "pcx",
00255     .type           = AVMEDIA_TYPE_VIDEO,
00256     .id             = CODEC_ID_PCX,
00257     .priv_data_size = sizeof(PCXContext),
00258     .init           = pcx_init,
00259     .close          = pcx_end,
00260     .decode         = pcx_decode_frame,
00261     .capabilities   = CODEC_CAP_DR1,
00262     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
00263 };