libavcodec/tiertexseqv.c

   1 /*
   2  * Tiertex Limited SEQ Video Decoder
   3  * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.net)
   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 tiertexseqv.c
  24  * Tiertex Limited SEQ video decoder
  25  */
  26
  27 #include "avcodec.h"
  28 #define ALT_BITSTREAM_READER_LE
  29 #include "bitstream.h"
  30
  31
  32 typedef struct SeqVideoContext {
  33     AVCodecContext *avctx;
  34     AVFrame frame;
  35     unsigned int palette[256];
  36     unsigned char block[8 * 8];
  37 } SeqVideoContext;
  38
  39
  40 static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsigned char *dst, int dst_size)
  41 {
  42     int i, len, sz;
  43     GetBitContext gb;
  44     int code_table[64];
  45
  46     /* get the rle codes (at most 64 bytes) */
  47     init_get_bits(&gb, src, 64 * 8);
  48     for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
  49         code_table[i] = get_sbits(&gb, 4);
  50         sz += FFABS(code_table[i]);
  51     }
  52     src += (get_bits_count(&gb) + 7) / 8;
  53
  54     /* do the rle unpacking */
  55     for (i = 0; i < 64 && dst_size > 0; i++) {
  56         len = code_table[i];
  57         if (len < 0) {
  58             len = -len;
  59             memset(dst, *src++, FFMIN(len, dst_size));
  60         } else {
  61             memcpy(dst, src, FFMIN(len, dst_size));
  62             src += len;
  63         }
  64         dst += len;
  65         dst_size -= len;
  66     }
  67     return src;
  68 }
  69
  70 static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
  71 {
  72     const unsigned char *color_table;
  73     int b, i, len, bits;
  74     GetBitContext gb;
  75
  76     len = *src++;
  77     if (len & 0x80) {
  78         switch (len & 3) {
  79         case 1:
  80             src = seq_unpack_rle_block(src, seq->block, sizeof(seq->block));
  81             for (b = 0; b < 8; b++) {
  82                 memcpy(dst, &seq->block[b * 8], 8);
  83                 dst += seq->frame.linesize[0];
  84             }
  85             break;
  86         case 2:
  87             src = seq_unpack_rle_block(src, seq->block, sizeof(seq->block));
  88             for (i = 0; i < 8; i++) {
  89                 for (b = 0; b < 8; b++)
  90                     dst[b * seq->frame.linesize[0]] = seq->block[i * 8 + b];
  91                 ++dst;
  92             }
  93             break;
  94         }
  95     } else {
  96         color_table = src;
  97         src += len;
  98         bits = ff_log2_tab[len - 1] + 1;
  99         init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
 100         for (b = 0; b < 8; b++) {
 101             for (i = 0; i < 8; i++)
 102                 dst[i] = color_table[get_bits(&gb, bits)];
 103             dst += seq->frame.linesize[0];
 104         }
 105     }
 106
 107     return src;
 108 }
 109
 110 static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
 111 {
 112     int i;
 113
 114     for (i = 0; i < 8; i++) {
 115         memcpy(dst, src, 8);
 116         src += 8;
 117         dst += seq->frame.linesize[0];
 118     }
 119
 120     return src;
 121 }
 122
 123 static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
 124 {
 125     int pos, offset;
 126
 127     do {
 128         pos = *src++;
 129         offset = ((pos >> 3) & 7) * seq->frame.linesize[0] + (pos & 7);
 130         dst[offset] = *src++;
 131     } while (!(pos & 0x80));
 132
 133     return src;
 134 }
 135
 136 static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
 137 {
 138     GetBitContext gb;
 139     int flags, i, j, x, y, op;
 140     unsigned char c[3];
 141     unsigned char *dst;
 142
 143     flags = *data++;
 144
 145     if (flags & 1) {
 146         for (i = 0; i < 256; i++) {
 147             for (j = 0; j < 3; j++, data++)
 148                 c[j] = (*data << 2) | (*data >> 4);
 149             seq->palette[i] = AV_RB24(c);
 150         }
 151         memcpy(seq->frame.data[1], seq->palette, sizeof(seq->palette));
 152         seq->frame.palette_has_changed = 1;
 153     }
 154
 155     if (flags & 2) {
 156         init_get_bits(&gb, data, 128 * 8); data += 128;
 157         for (y = 0; y < 128; y += 8)
 158             for (x = 0; x < 256; x += 8) {
 159                 dst = &seq->frame.data[0][y * seq->frame.linesize[0] + x];
 160                 op = get_bits(&gb, 2);
 161                 switch (op) {
 162                 case 1:
 163                     data = seq_decode_op1(seq, data, dst);
 164                     break;
 165                 case 2:
 166                     data = seq_decode_op2(seq, data, dst);
 167                     break;
 168                 case 3:
 169                     data = seq_decode_op3(seq, data, dst);
 170                     break;
 171                 }
 172             }
 173     }
 174 }
 175
 176 static av_cold int seqvideo_decode_init(AVCodecContext *avctx)
 177 {
 178     SeqVideoContext *seq = avctx->priv_data;
 179
 180     seq->avctx = avctx;
 181     avctx->pix_fmt = PIX_FMT_PAL8;
 182
 183     seq->frame.data[0] = NULL;
 184
 185     return 0;
 186 }
 187
 188 static av_cold int seqvideo_decode_frame(AVCodecContext *avctx,
 189                                  void *data, int *data_size,
 190                                  const uint8_t *buf, int buf_size)
 191 {
 192
 193     SeqVideoContext *seq = avctx->priv_data;
 194
 195     seq->frame.reference = 1;
 196     seq->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 197     if (avctx->reget_buffer(avctx, &seq->frame)) {
 198         av_log(seq->avctx, AV_LOG_ERROR, "tiertexseqvideo: reget_buffer() failed\n");
 199         return -1;
 200     }
 201
 202     seqvideo_decode(seq, buf, buf_size);
 203
 204     *data_size = sizeof(AVFrame);
 205     *(AVFrame *)data = seq->frame;
 206
 207     return buf_size;
 208 }
 209
 210 static int seqvideo_decode_end(AVCodecContext *avctx)
 211 {
 212     SeqVideoContext *seq = avctx->priv_data;
 213
 214     if (seq->frame.data[0])
 215         avctx->release_buffer(avctx, &seq->frame);
 216
 217     return 0;
 218 }
 219
 220 AVCodec tiertexseqvideo_decoder = {
 221     "tiertexseqvideo",
 222     CODEC_TYPE_VIDEO,
 223     CODEC_ID_TIERTEXSEQVIDEO,
 224     sizeof(SeqVideoContext),
 225     seqvideo_decode_init,
 226     NULL,
 227     seqvideo_decode_end,
 228     seqvideo_decode_frame,
 229     CODEC_CAP_DR1,
 230     .long_name = "Tiertex Limited SEQ video",
 231 };