libavcodec/qpeg.c

   1 /*
   2  * QPEG codec
   3  * Copyright (c) 2004 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  24  * QPEG codec.
  25  */
  26
  27 #include "avcodec.h"
  28 #include "bytestream.h"
  29
  30 typedef struct QpegContext{
  31     AVCodecContext *avctx;
  32     AVFrame pic;
  33     uint8_t *refdata;
  34     uint32_t pal[256];
  35     GetByteContext buffer;
  36 } QpegContext;
  37
  38 static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
  39                               int stride, int width, int height)
  40 {
  41     int i;
  42     int code;
  43     int c0, c1;
  44     int run, copy;
  45     int filled = 0;
  46     int rows_to_go;
  47
  48     rows_to_go = height;
  49     height--;
  50     dst = dst + height * stride;
  51
  52     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
  53         code = bytestream2_get_byte(&qctx->buffer);
  54         run = copy = 0;
  55         if(code == 0xFC) /* end-of-picture code */
  56             break;
  57         if(code >= 0xF8) { /* very long run */
  58             c0 = bytestream2_get_byte(&qctx->buffer);
  59             c1 = bytestream2_get_byte(&qctx->buffer);
  60             run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
  61         } else if (code >= 0xF0) { /* long run */
  62             c0 = bytestream2_get_byte(&qctx->buffer);
  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 = bytestream2_get_byte(&qctx->buffer);
  68             c1 = bytestream2_get_byte(&qctx->buffer);
  69             copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
  70         } else if (code >= 0x80) { /* long copy */
  71             c0 = bytestream2_get_byte(&qctx->buffer);
  72             copy = ((code & 0x7F) << 8) + c0 + 1;
  73         } else { /* short copy */
  74             copy = code + 1;
  75         }
  76
  77         /* perform actual run or copy */
  78         if(run) {
  79             int p;
  80
  81             p = bytestream2_get_byte(&qctx->buffer);
  82             for(i = 0; i < run; i++) {
  83                 dst[filled++] = p;
  84                 if (filled >= width) {
  85                     filled = 0;
  86                     dst -= stride;
  87                     rows_to_go--;
  88                     if(rows_to_go <= 0)
  89                         break;
  90                 }
  91             }
  92         } else {
  93             for(i = 0; i < copy; i++) {
  94                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
  95                 if (filled >= width) {
  96                     filled = 0;
  97                     dst -= stride;
  98                     rows_to_go--;
  99                     if(rows_to_go <= 0)
 100                         break;
 101                 }
 102             }
 103         }
 104     }
 105 }
 106
 107 static const int qpeg_table_h[16] =
 108  { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
 109 static const int qpeg_table_w[16] =
 110  { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
 111
 112 /* Decodes delta frames */
 113 static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
 114                               int stride, int width, int height,
 115                               int delta, const uint8_t *ctable,
 116                               uint8_t *refdata)
 117 {
 118     int i, j;
 119     int code;
 120     int filled = 0;
 121     int orig_height;
 122
 123     /* copy prev frame */
 124     for(i = 0; i < height; i++)
 125         memcpy(refdata + (i * width), dst + (i * stride), width);
 126
 127     orig_height = height;
 128     height--;
 129     dst = dst + height * stride;
 130
 131     while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
 132         code = bytestream2_get_byte(&qctx->buffer);
 133
 134         if(delta) {
 135             /* motion compensation */
 136             while((code & 0xF0) == 0xF0) {
 137                 if(delta == 1) {
 138                     int me_idx;
 139                     int me_w, me_h, me_x, me_y;
 140                     uint8_t *me_plane;
 141                     int corr, val;
 142
 143                     /* get block size by index */
 144                     me_idx = code & 0xF;
 145                     me_w = qpeg_table_w[me_idx];
 146                     me_h = qpeg_table_h[me_idx];
 147
 148                     /* extract motion vector */
 149                     corr = bytestream2_get_byte(&qctx->buffer);
 150
 151                     val = corr >> 4;
 152                     if(val > 7)
 153                         val -= 16;
 154                     me_x = val;
 155
 156                     val = corr & 0xF;
 157                     if(val > 7)
 158                         val -= 16;
 159                     me_y = val;
 160
 161                     /* check motion vector */
 162                     if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
 163                        (height - me_y - me_h < 0) || (height - me_y > orig_height) ||
 164                        (filled + me_w > width) || (height - me_h < 0))
 165                         av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
 166                                me_x, me_y, me_w, me_h, filled, height);
 167                     else {
 168                         /* do motion compensation */
 169                         me_plane = refdata + (filled + me_x) + (height - me_y) * width;
 170                         for(j = 0; j < me_h; j++) {
 171                             for(i = 0; i < me_w; i++)
 172                                 dst[filled + i - (j * stride)] = me_plane[i - (j * width)];
 173                         }
 174                     }
 175                 }
 176                 code = bytestream2_get_byte(&qctx->buffer);
 177             }
 178         }
 179
 180         if(code == 0xE0) /* end-of-picture code */
 181             break;
 182         if(code > 0xE0) { /* run code: 0xE1..0xFF */
 183             int p;
 184
 185             code &= 0x1F;
 186             p = bytestream2_get_byte(&qctx->buffer);
 187             for(i = 0; i <= code; i++) {
 188                 dst[filled++] = p;
 189                 if(filled >= width) {
 190                     filled = 0;
 191                     dst -= stride;
 192                     height--;
 193                 }
 194             }
 195         } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
 196             code &= 0x1F;
 197
 198             for(i = 0; i <= code; i++) {
 199                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
 200                 if(filled >= width) {
 201                     filled = 0;
 202                     dst -= stride;
 203                     height--;
 204                 }
 205             }
 206         } else if(code >= 0x80) { /* skip code: 0x80..0xBF */
 207             int skip;
 208
 209             code &= 0x3F;
 210             /* codes 0x80 and 0x81 are actually escape codes,
 211                skip value minus constant is in the next byte */
 212             if(!code)
 213                 skip = bytestream2_get_byte(&qctx->buffer) +  64;
 214             else if(code == 1)
 215                 skip = bytestream2_get_byte(&qctx->buffer) + 320;
 216             else
 217                 skip = code;
 218             filled += skip;
 219             while( filled >= width) {
 220                 filled -= width;
 221                 dst -= stride;
 222                 height--;
 223                 if(height < 0)
 224                     break;
 225             }
 226         } else {
 227             /* zero code treated as one-pixel skip */
 228             if(code) {
 229                 dst[filled++] = ctable[code & 0x7F];
 230             }
 231             else
 232                 filled++;
 233             if(filled >= width) {
 234                 filled = 0;
 235                 dst -= stride;
 236                 height--;
 237             }
 238         }
 239     }
 240 }
 241
 242 static int decode_frame(AVCodecContext *avctx,
 243                         void *data, int *got_frame,
 244                         AVPacket *avpkt)
 245 {
 246     uint8_t ctable[128];
 247     QpegContext * const a = avctx->priv_data;
 248     AVFrame * const p = &a->pic;
 249     uint8_t* outdata;
 250     int delta, ret;
 251     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 252
 253     if (avpkt->size < 0x86) {
 254         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
 255         return AVERROR_INVALIDDATA;
 256     }
 257
 258     bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
 259     p->reference = 3;
 260     if ((ret = avctx->reget_buffer(avctx, p)) < 0) {
 261         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 262         return ret;
 263     }
 264     outdata = a->pic.data[0];
 265     bytestream2_skip(&a->buffer, 4);
 266     bytestream2_get_buffer(&a->buffer, ctable, 128);
 267     bytestream2_skip(&a->buffer, 1);
 268
 269     delta = bytestream2_get_byte(&a->buffer);
 270     if(delta == 0x10) {
 271         qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);
 272     } else {
 273         qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->refdata);
 274     }
 275
 276     /* make the palette available on the way out */
 277     if (pal) {
 278         a->pic.palette_has_changed = 1;
 279         memcpy(a->pal, pal, AVPALETTE_SIZE);
 280     }
 281     memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
 282
 283     *got_frame      = 1;
 284     *(AVFrame*)data = a->pic;
 285
 286     return avpkt->size;
 287 }
 288
 289 static av_cold int decode_init(AVCodecContext *avctx){
 290     QpegContext * const a = avctx->priv_data;
 291
 292     a->avctx = avctx;
 293     avctx->pix_fmt= AV_PIX_FMT_PAL8;
 294     a->refdata = av_malloc(avctx->width * avctx->height);
 295
 296     return 0;
 297 }
 298
 299 static av_cold int decode_end(AVCodecContext *avctx){
 300     QpegContext * const a = avctx->priv_data;
 301     AVFrame * const p = &a->pic;
 302
 303     if(p->data[0])
 304         avctx->release_buffer(avctx, p);
 305
 306     av_free(a->refdata);
 307     return 0;
 308 }
 309
 310 AVCodec ff_qpeg_decoder = {
 311     .name           = "qpeg",
 312     .type           = AVMEDIA_TYPE_VIDEO,
 313     .id             = AV_CODEC_ID_QPEG,
 314     .priv_data_size = sizeof(QpegContext),
 315     .init           = decode_init,
 316     .close          = decode_end,
 317     .decode         = decode_frame,
 318     .capabilities   = CODEC_CAP_DR1,
 319     .long_name      = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
 320 };