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 libavcodec/tiertexseqv.c
  24  * Tiertex Limited SEQ video decoder
  25  */
  26
  27 #include "avcodec.h"
  28 #define ALT_BITSTREAM_READER_LE
  29 #include "get_bits.h"
  30
  31
  32 typedef struct SeqVideoContext {
  33     AVCodecContext *avctx;
  34     AVFrame frame;
  35 } SeqVideoContext;
  36
  37
  38 static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsigned char *dst, int dst_size)
  39 {
  40     int i, len, sz;
  41     GetBitContext gb;
  42     int code_table[64];
  43
  44     /* get the rle codes (at most 64 bytes) */
  45     init_get_bits(&gb, src, 64 * 8);
  46     for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
  47         code_table[i] = get_sbits(&gb, 4);
  48         sz += FFABS(code_table[i]);
  49     }
  50     src += (get_bits_count(&gb) + 7) / 8;
  51
  52     /* do the rle unpacking */
  53     for (i = 0; i < 64 && dst_size > 0; i++) {
  54         len = code_table[i];
  55         if (len < 0) {
  56             len = -len;
  57             memset(dst, *src++, FFMIN(len, dst_size));
  58         } else {
  59             memcpy(dst, src, FFMIN(len, dst_size));
  60             src += len;
  61         }
  62         dst += len;
  63         dst_size -= len;
  64     }
  65     return src;
  66 }
  67
  68 static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
  69 {
  70     const unsigned char *color_table;
  71     int b, i, len, bits;
  72     GetBitContext gb;
  73     unsigned char block[8 * 8];
  74
  75     len = *src++;
  76     if (len & 0x80) {
  77         switch (len & 3) {
  78         case 1:
  79             src = seq_unpack_rle_block(src, block, sizeof(block));
  80             for (b = 0; b < 8; b++) {
  81                 memcpy(dst, &block[b * 8], 8);
  82                 dst += seq->frame.linesize[0];
  83             }
  84             break;
  85         case 2:
  86             src = seq_unpack_rle_block(src, block, sizeof(block));
  87             for (i = 0; i < 8; i++) {
  88                 for (b = 0; b < 8; b++)
  89                     dst[b * seq->frame.linesize[0]] = block[i * 8 + b];
  90                 ++dst;
  91             }
  92             break;
  93         }
  94     } else {
  95         color_table = src;
  96         src += len;
  97         bits = ff_log2_tab[len - 1] + 1;
  98         init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
  99         for (b = 0; b < 8; b++) {
 100             for (i = 0; i < 8; i++)
 101                 dst[i] = color_table[get_bits(&gb, bits)];
 102             dst += seq->frame.linesize[0];
 103         }
 104     }
 105
 106     return src;
 107 }
 108
 109 static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
 110 {
 111     int i;
 112
 113     for (i = 0; i < 8; i++) {
 114         memcpy(dst, src, 8);
 115         src += 8;
 116         dst += seq->frame.linesize[0];
 117     }
 118
 119     return src;
 120 }
 121
 122 static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
 123 {
 124     int pos, offset;
 125
 126     do {
 127         pos = *src++;
 128         offset = ((pos >> 3) & 7) * seq->frame.linesize[0] + (pos & 7);
 129         dst[offset] = *src++;
 130     } while (!(pos & 0x80));
 131
 132     return src;
 133 }
 134
 135 static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
 136 {
 137     GetBitContext gb;
 138     int flags, i, j, x, y, op;
 139     unsigned char c[3];
 140     unsigned char *dst;
 141     uint32_t *palette;
 142
 143     flags = *data++;
 144
 145     if (flags & 1) {
 146         palette = (uint32_t *)seq->frame.data[1];
 147         for (i = 0; i < 256; i++) {
 148             for (j = 0; j < 3; j++, data++)
 149                 c[j] = (*data << 2) | (*data >> 4);
 150             palette[i] = AV_RB24(c);
 151         }
 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 int seqvideo_decode_frame(AVCodecContext *avctx,
 189                                  void *data, int *data_size,
 190                                  AVPacket *avpkt)
 191 {
 192     const uint8_t *buf = avpkt->data;
 193     int buf_size = avpkt->size;
 194
 195     SeqVideoContext *seq = avctx->priv_data;
 196
 197     seq->frame.reference = 1;
 198     seq->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 199     if (avctx->reget_buffer(avctx, &seq->frame)) {
 200         av_log(seq->avctx, AV_LOG_ERROR, "tiertexseqvideo: reget_buffer() failed\n");
 201         return -1;
 202     }
 203
 204     seqvideo_decode(seq, buf, buf_size);
 205
 206     *data_size = sizeof(AVFrame);
 207     *(AVFrame *)data = seq->frame;
 208
 209     return buf_size;
 210 }
 211
 212 static av_cold int seqvideo_decode_end(AVCodecContext *avctx)
 213 {
 214     SeqVideoContext *seq = avctx->priv_data;
 215
 216     if (seq->frame.data[0])
 217         avctx->release_buffer(avctx, &seq->frame);
 218
 219     return 0;
 220 }
 221
 222 AVCodec tiertexseqvideo_decoder = {
 223     "tiertexseqvideo",
 224     CODEC_TYPE_VIDEO,
 225     CODEC_ID_TIERTEXSEQVIDEO,
 226     sizeof(SeqVideoContext),
 227     seqvideo_decode_init,
 228     NULL,
 229     seqvideo_decode_end,
 230     seqvideo_decode_frame,
 231     CODEC_CAP_DR1,
 232     .long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
 233 };