libavcodec/qpeg.c

   1 /*
   2  * QPEG codec
   3  * Copyright (c) 2004 Konstantin Shishkov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file libavcodec/qpeg.c
  24  * QPEG codec.
  25  */
  26
  27 #include "avcodec.h"
  28
  29 typedef struct QpegContext{
  30     AVCodecContext *avctx;
  31     AVFrame pic;
  32     uint8_t *refdata;
  33 } QpegContext;
  34
  35 static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
  36                             int stride, int width, int height)
  37 {
  38     int i;
  39     int code;
  40     int c0, c1;
  41     int run, copy;
  42     int filled = 0;
  43     int rows_to_go;
  44
  45     rows_to_go = height;
  46     height--;
  47     dst = dst + height * stride;
  48
  49     while((size > 0) && (rows_to_go > 0)) {
  50         code = *src++;
  51         size--;
  52         run = copy = 0;
  53         if(code == 0xFC) /* end-of-picture code */
  54             break;
  55         if(code >= 0xF8) { /* very long run */
  56             c0 = *src++;
  57             c1 = *src++;
  58             size -= 2;
  59             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
  60         } else if (code >= 0xF0) { /* long run */
  61             c0 = *src++;
  62             size--;
  63             run = ((code & 0xF) << 8) + c0 + 2;
  64         } else if (code >= 0xE0) { /* short run */
  65             run = (code & 0x1F) + 2;
  66         } else if (code >= 0xC0) { /* very long copy */
  67             c0 = *src++;
  68             c1 = *src++;
  69             size -= 2;
  70             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
  71         } else if (code >= 0x80) { /* long copy */
  72             c0 = *src++;
  73             size--;
  74             copy = ((code & 0x7F) << 8) + c0 + 1;
  75         } else { /* short copy */
  76             copy = code + 1;
  77         }
  78
  79         /* perform actual run or copy */
  80         if(run) {
  81             int p;
  82
  83             p = *src++;
  84             size--;
  85             for(i = 0; i < run; i++) {
  86                 dst[filled++] = p;
  87                 if (filled >= width) {
  88                     filled = 0;
  89                     dst -= stride;
  90                     rows_to_go--;
  91                     if(rows_to_go <= 0)
  92                         break;
  93                 }
  94             }
  95         } else {
  96             size -= copy;
  97             for(i = 0; i < copy; i++) {
  98                 dst[filled++] = *src++;
  99                 if (filled >= width) {
 100                     filled = 0;
 101                     dst -= stride;
 102                     rows_to_go--;
 103                     if(rows_to_go <= 0)
 104                         break;
 105                 }
 106             }
 107         }
 108     }
 109 }
 110
 111 static const int qpeg_table_h[16] =
 112  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
 113 static const int qpeg_table_w[16] =
 114  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
 115
 116 /* Decodes delta frames */
 117 static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
 118                             int stride, int width, int height,
 119                             int delta, const uint8_t *ctable, uint8_t *refdata)
 120 {
 121     int i, j;
 122     int code;
 123     int filled = 0;
 124     int orig_height;
 125
 126     /* copy prev frame */
 127     for(i = 0; i < height; i++)
 128         memcpy(refdata + (i * width), dst + (i * stride), width);
 129
 130     orig_height = height;
 131     height--;
 132     dst = dst + height * stride;
 133
 134     while((size > 0) && (height >= 0)) {
 135         code = *src++;
 136         size--;
 137
 138         if(delta) {
 139             /* motion compensation */
 140             while((code & 0xF0) == 0xF0) {
 141                 if(delta == 1) {
 142                     int me_idx;
 143                     int me_w, me_h, me_x, me_y;
 144                     uint8_t *me_plane;
 145                     int corr, val;
 146
 147                     /* get block size by index */
 148                     me_idx = code & 0xF;
 149                     me_w = qpeg_table_w[me_idx];
 150                     me_h = qpeg_table_h[me_idx];
 151
 152                     /* extract motion vector */
 153                     corr = *src++;
 154                     size--;
 155
 156                     val = corr >> 4;
 157                     if(val > 7)
 158                         val -= 16;
 159                     me_x = val;
 160
 161                     val = corr & 0xF;
 162                     if(val > 7)
 163                         val -= 16;
 164                     me_y = val;
 165
 166                     /* check motion vector */
 167                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
 168                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
 169                        (filled + me_w > width) || (height - me_h < 0))
 170                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
 171                                me_x, me_y, me_w, me_h, filled, height);
 172                     else {
 173                         /* do motion compensation */
 174                         me_plane = refdata + (filled + me_x) + (height - me_y) * width;
 175                         for(j = 0; j < me_h; j++) {
 176                             for(i = 0; i < me_w; i++)
 177                                 dst[filled + i - (j * stride)] = me_plane[i - (j * width)];
 178                         }
 179                     }
 180                 }
 181                 code = *src++;
 182                 size--;
 183             }
 184         }
 185
 186         if(code == 0xE0) /* end-of-picture code */
 187             break;
 188         if(code > 0xE0) { /* run code: 0xE1..0xFF */
 189             int p;
 190
 191             code &= 0x1F;
 192             p = *src++;
 193             size--;
 194             for(i = 0; i <= code; i++) {
 195                 dst[filled++] = p;
 196                 if(filled >= width) {
 197                     filled = 0;
 198                     dst -= stride;
 199                     height--;
 200                 }
 201             }
 202         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
 203             code &= 0x1F;
 204
 205             for(i = 0; i <= code; i++) {
 206                 dst[filled++] = *src++;
 207                 if(filled >= width) {
 208                     filled = 0;
 209                     dst -= stride;
 210                     height--;
 211                 }
 212             }
 213             size -= code + 1;
 214         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
 215             int skip;
 216
 217             code &= 0x3F;
 218             /* codes 0x80 and 0x81 are actually escape codes,
 219                skip value minus constant is in the next byte */
 220             if(!code)
 221                 skip = (*src++) + 64;
 222             else if(code == 1)
 223                 skip = (*src++) + 320;
 224             else
 225                 skip = code;
 226             filled += skip;
 227             while( filled >= width) {
 228                 filled -= width;
 229                 dst -= stride;
 230                 height--;
 231                 if(height < 0)
 232                     break;
 233             }
 234         } else {
 235             /* zero code treated as one-pixel skip */
 236             if(code)
 237                 dst[filled++] = ctable[code & 0x7F];
 238             else
 239                 filled++;
 240             if(filled >= width) {
 241                 filled = 0;
 242                 dst -= stride;
 243                 height--;
 244             }
 245         }
 246     }
 247 }
 248
 249 static int decode_frame(AVCodecContext *avctx,
 250                         void *data, int *data_size,
 251                         const uint8_t *buf, int buf_size)
 252 {
 253     QpegContext * const a = avctx->priv_data;
 254     AVFrame * const p= (AVFrame*)&a->pic;
 255     uint8_t* outdata;
 256     int delta;
 257
 258     if(p->data[0])
 259         avctx->release_buffer(avctx, p);
 260
 261     p->reference= 0;
 262     if(avctx->get_buffer(avctx, p) < 0){
 263         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 264         return -1;
 265     }
 266     outdata = a->pic.data[0];
 267     if(buf[0x85] == 0x10) {
 268         qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);
 269     } else {
 270         delta = buf[0x85];
 271         qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->refdata);
 272     }
 273
 274     /* make the palette available on the way out */
 275     memcpy(a->pic.data[1], a->avctx->palctrl->palette, AVPALETTE_SIZE);
 276     if (a->avctx->palctrl->palette_changed) {
 277         a->pic.palette_has_changed = 1;
 278         a->avctx->palctrl->palette_changed = 0;
 279     }
 280
 281     *data_size = sizeof(AVFrame);
 282     *(AVFrame*)data = a->pic;
 283
 284     return buf_size;
 285 }
 286
 287 static av_cold int decode_init(AVCodecContext *avctx){
 288     QpegContext * const a = avctx->priv_data;
 289
 290     a->avctx = avctx;
 291     avctx->pix_fmt= PIX_FMT_PAL8;
 292     a->pic.data[0] = NULL;
 293     a->refdata = av_malloc(avctx->width * avctx->height);
 294
 295     return 0;
 296 }
 297
 298 static av_cold int decode_end(AVCodecContext *avctx){
 299     QpegContext * const a = avctx->priv_data;
 300     AVFrame * const p= (AVFrame*)&a->pic;
 301
 302     if(p->data[0])
 303         avctx->release_buffer(avctx, p);
 304
 305     av_free(a->refdata);
 306     return 0;
 307 }
 308
 309 AVCodec qpeg_decoder = {
 310     "qpeg",
 311     CODEC_TYPE_VIDEO,
 312     CODEC_ID_QPEG,
 313     sizeof(QpegContext),
 314     decode_init,
 315     NULL,
 316     decode_end,
 317     decode_frame,
 318     CODEC_CAP_DR1,
 319     .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
 320 };