Libav 0.7.1
libavcodec/pictordec.c
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00001 /*
00002  * Pictor/PC Paint decoder
00003  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #include "libavutil/imgutils.h"
00028 #include "avcodec.h"
00029 #include "bytestream.h"
00030 #include "cga_data.h"
00031 
00032 typedef struct PicContext {
00033     AVFrame frame;
00034     int width, height;
00035     int nb_planes;
00036 } PicContext;
00037 
00038 static void picmemset_8bpp(PicContext *s, int value, int run, int *x, int *y)
00039 {
00040     while (run > 0) {
00041         uint8_t *d = s->frame.data[0] + *y * s->frame.linesize[0];
00042         if (*x + run >= s->width) {
00043             int n = s->width - *x;
00044             memset(d + *x, value, n);
00045             run -= n;
00046             *x = 0;
00047             *y -= 1;
00048             if (*y < 0)
00049                 break;
00050         } else {
00051             memset(d + *x, value, run);
00052             *x += run;
00053             break;
00054         }
00055     }
00056 }
00057 
00058 static void picmemset(PicContext *s, int value, int run, int *x, int *y, int *plane, int bits_per_plane)
00059 {
00060     uint8_t *d;
00061     int shift = *plane * bits_per_plane;
00062     int mask  = ((1 << bits_per_plane) - 1) << shift;
00063     value   <<= shift;
00064 
00065     while (run > 0) {
00066         int j;
00067         for (j = 8-bits_per_plane; j >= 0; j -= bits_per_plane) {
00068             d = s->frame.data[0] + *y * s->frame.linesize[0];
00069             d[*x] |= (value >> j) & mask;
00070             *x += 1;
00071             if (*x == s->width) {
00072                 *y -= 1;
00073                 *x = 0;
00074                 if (*y < 0) {
00075                    *y = s->height - 1;
00076                    *plane += 1;
00077                    value <<= bits_per_plane;
00078                    mask  <<= bits_per_plane;
00079                    if (*plane >= s->nb_planes)
00080                        break;
00081                 }
00082             }
00083         }
00084         run--;
00085     }
00086 }
00087 
00088 static const uint8_t cga_mode45_index[6][4] = {
00089     [0] = { 0, 3,  5,   7 }, // mode4, palette#1, low intensity
00090     [1] = { 0, 2,  4,   6 }, // mode4, palette#2, low intensity
00091     [2] = { 0, 3,  4,   7 }, // mode5, low intensity
00092     [3] = { 0, 11, 13, 15 }, // mode4, palette#1, high intensity
00093     [4] = { 0, 10, 12, 14 }, // mode4, palette#2, high intensity
00094     [5] = { 0, 11, 12, 15 }, // mode5, high intensity
00095 };
00096 
00097 static int decode_frame(AVCodecContext *avctx,
00098                         void *data, int *data_size,
00099                         AVPacket *avpkt)
00100 {
00101     PicContext *s = avctx->priv_data;
00102     int buf_size = avpkt->size;
00103     const uint8_t *buf = avpkt->data;
00104     const uint8_t *buf_end = avpkt->data + buf_size;
00105     uint32_t *palette;
00106     int bits_per_plane, bpp, etype, esize, npal;
00107     int i, x, y, plane;
00108 
00109     if (buf_size < 11)
00110         return AVERROR_INVALIDDATA;
00111 
00112     if (bytestream_get_le16(&buf) != 0x1234)
00113         return AVERROR_INVALIDDATA;
00114     s->width  = bytestream_get_le16(&buf);
00115     s->height = bytestream_get_le16(&buf);
00116     buf += 4;
00117     bits_per_plane    = *buf & 0xF;
00118     s->nb_planes      = (*buf++ >> 4) + 1;
00119     bpp               = s->nb_planes ? bits_per_plane*s->nb_planes : bits_per_plane;
00120     if (bits_per_plane > 8 || bpp < 1 || bpp > 32) {
00121         av_log_ask_for_sample(s, "unsupported bit depth\n");
00122         return AVERROR_INVALIDDATA;
00123     }
00124 
00125     if (*buf == 0xFF) {
00126         buf += 2;
00127         etype  = bytestream_get_le16(&buf);
00128         esize  = bytestream_get_le16(&buf);
00129         if (buf_end - buf < esize)
00130             return AVERROR_INVALIDDATA;
00131     } else {
00132         etype = -1;
00133         esize = 0;
00134     }
00135 
00136     avctx->pix_fmt = PIX_FMT_PAL8;
00137 
00138     if (s->width != avctx->width && s->height != avctx->height) {
00139         if (av_image_check_size(s->width, s->height, 0, avctx) < 0)
00140             return -1;
00141         avcodec_set_dimensions(avctx, s->width, s->height);
00142         if (s->frame.data[0])
00143             avctx->release_buffer(avctx, &s->frame);
00144     }
00145 
00146     if (avctx->get_buffer(avctx, &s->frame) < 0){
00147         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00148         return -1;
00149     }
00150     memset(s->frame.data[0], 0, s->height * s->frame.linesize[0]);
00151     s->frame.pict_type           = AV_PICTURE_TYPE_I;
00152     s->frame.palette_has_changed = 1;
00153 
00154     palette = (uint32_t*)s->frame.data[1];
00155     if (etype == 1 && esize > 1 && *buf < 6) {
00156         int idx = *buf;
00157         npal = 4;
00158         for (i = 0; i < npal; i++)
00159             palette[i] = ff_cga_palette[ cga_mode45_index[idx][i] ];
00160     } else if (etype == 2) {
00161         npal = FFMIN(esize, 16);
00162         for (i = 0; i < npal; i++)
00163             palette[i] = ff_cga_palette[ FFMIN(buf[i], 16)];
00164     } else if (etype == 3) {
00165         npal = FFMIN(esize, 16);
00166         for (i = 0; i < npal; i++)
00167             palette[i] = ff_ega_palette[ FFMIN(buf[i], 63)];
00168     } else if (etype == 4 || etype == 5) {
00169         npal = FFMIN(esize / 3, 256);
00170         for (i = 0; i < npal; i++)
00171             palette[i] = AV_RB24(buf + i*3) << 2;
00172     } else {
00173         if (bpp == 1) {
00174             npal = 2;
00175             palette[0] = 0x000000;
00176             palette[1] = 0xFFFFFF;
00177         } else if (bpp == 2) {
00178             npal = 4;
00179             for (i = 0; i < npal; i++)
00180                 palette[i] = ff_cga_palette[ cga_mode45_index[0][i] ];
00181         } else {
00182             npal = 16;
00183             memcpy(palette, ff_cga_palette, npal * 4);
00184         }
00185     }
00186     // fill remaining palette entries
00187     memset(palette + npal, 0, AVPALETTE_SIZE - npal * 4);
00188     buf += esize;
00189 
00190 
00191     x = 0;
00192     y = s->height - 1;
00193     plane = 0;
00194     if (bytestream_get_le16(&buf)) {
00195         while (buf_end - buf >= 6) {
00196             const uint8_t *buf_pend = buf + FFMIN(AV_RL16(buf), buf_end - buf);
00197             //ignore uncompressed block size reported at buf[2]
00198             int marker = buf[4];
00199             buf += 5;
00200 
00201             while (plane < s->nb_planes && buf_pend - buf >= 1) {
00202                 int run = 1;
00203                 int val = *buf++;
00204                 if (val == marker) {
00205                     run = *buf++;
00206                     if (run == 0)
00207                         run = bytestream_get_le16(&buf);
00208                     val = *buf++;
00209                 }
00210                 if (buf > buf_end)
00211                     break;
00212 
00213                 if (bits_per_plane == 8) {
00214                     picmemset_8bpp(s, val, run, &x, &y);
00215                     if (y < 0)
00216                         break;
00217                 } else {
00218                     picmemset(s, val, run, &x, &y, &plane, bits_per_plane);
00219                 }
00220             }
00221         }
00222     } else {
00223         av_log_ask_for_sample(s, "uncompressed image\n");
00224         return buf_size;
00225     }
00226 
00227     *data_size = sizeof(AVFrame);
00228     *(AVFrame*)data = s->frame;
00229     return buf_size;
00230 }
00231 
00232 static av_cold int decode_end(AVCodecContext *avctx)
00233 {
00234     PicContext *s = avctx->priv_data;
00235     if (s->frame.data[0])
00236         avctx->release_buffer(avctx, &s->frame);
00237     return 0;
00238 }
00239 
00240 AVCodec ff_pictor_decoder = {
00241     "pictor",
00242     AVMEDIA_TYPE_VIDEO,
00243     CODEC_ID_PICTOR,
00244     sizeof(PicContext),
00245     NULL,
00246     NULL,
00247     decode_end,
00248     decode_frame,
00249     CODEC_CAP_DR1,
00250     .long_name = NULL_IF_CONFIG_SMALL("Pictor/PC Paint"),
00251 };