libavcodec/bfi.c

   1 /*
   2  * Brute Force & Ignorance (BFI) video decoder
   3  * Copyright (c) 2008 Sisir Koppaka
   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
  24  * @brief Brute Force & Ignorance (.bfi) video decoder
  25  * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
  26  * @see http://wiki.multimedia.cx/index.php?title=BFI
  27  */
  28
  29 #include "libavutil/mem.h"
  30 #include "avcodec.h"
  31 #include "bytestream.h"
  32 #include "codec_internal.h"
  33 #include "decode.h"
  34
  35 typedef struct BFIContext {
  36     uint8_t *dst;
  37     uint32_t pal[256];
  38 } BFIContext;
  39
  40 static av_cold int bfi_decode_init(AVCodecContext *avctx)
  41 {
  42     BFIContext *bfi = avctx->priv_data;
  43     avctx->pix_fmt  = AV_PIX_FMT_PAL8;
  44     bfi->dst        = av_mallocz(avctx->width * avctx->height);
  45     if (!bfi->dst)
  46         return AVERROR(ENOMEM);
  47     return 0;
  48 }
  49
  50 static int bfi_decode_frame(AVCodecContext *avctx, AVFrame *frame,
  51                             int *got_frame, AVPacket *avpkt)
  52 {
  53     GetByteContext g;
  54     int buf_size    = avpkt->size;
  55     BFIContext *bfi = avctx->priv_data;
  56     uint8_t *dst    = bfi->dst;
  57     uint8_t *src, *dst_offset, colour1, colour2;
  58     uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
  59     uint32_t *pal;
  60     int i, j, ret, height = avctx->height;
  61
  62     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
  63         return ret;
  64
  65     bytestream2_init(&g, avpkt->data, buf_size);
  66
  67     /* Set frame parameters and palette, if necessary */
  68     if (!avctx->frame_num) {
  69         frame->pict_type = AV_PICTURE_TYPE_I;
  70         frame->flags |= AV_FRAME_FLAG_KEY;
  71         /* Setting the palette */
  72         if (avctx->extradata_size > 768) {
  73             av_log(avctx, AV_LOG_ERROR, "Palette is too large.\n");
  74             return AVERROR_INVALIDDATA;
  75         }
  76         pal = (uint32_t *)frame->data[1];
  77         for (i = 0; i < avctx->extradata_size / 3; i++) {
  78             int shift = 16;
  79             *pal = 0xFFU << 24;
  80             for (j = 0; j < 3; j++, shift -= 8)
  81                 *pal += ((avctx->extradata[i * 3 + j] << 2) |
  82                          (avctx->extradata[i * 3 + j] >> 4)) << shift;
  83             pal++;
  84         }
  85         memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));
  86 #if FF_API_PALETTE_HAS_CHANGED
  87 FF_DISABLE_DEPRECATION_WARNINGS
  88         frame->palette_has_changed = 1;
  89 FF_ENABLE_DEPRECATION_WARNINGS
  90 #endif
  91     } else {
  92         frame->pict_type = AV_PICTURE_TYPE_P;
  93         frame->flags &= ~AV_FRAME_FLAG_KEY;
  94 #if FF_API_PALETTE_HAS_CHANGED
  95 FF_DISABLE_DEPRECATION_WARNINGS
  96         frame->palette_has_changed = 0;
  97 FF_ENABLE_DEPRECATION_WARNINGS
  98 #endif
  99         memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));
 100     }
 101
 102     bytestream2_skip(&g, 4); // Unpacked size, not required.
 103
 104     while (dst != frame_end) {
 105         static const uint8_t lentab[4] = { 0, 2, 0, 1 };
 106         unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);
 107         unsigned int code   = byte >> 6;
 108         unsigned int length = byte & ~0xC0;
 109
 110         if (!bytestream2_get_bytes_left(&g)) {
 111             av_log(avctx, AV_LOG_ERROR,
 112                    "Input resolution larger than actual frame.\n");
 113             return AVERROR_INVALIDDATA;
 114         }
 115
 116         /* Get length and offset (if required) */
 117         if (length == 0) {
 118             if (code == 1) {
 119                 length = bytestream2_get_byte(&g);
 120                 offset = bytestream2_get_le16(&g);
 121             } else {
 122                 length = bytestream2_get_le16(&g);
 123                 if (code == 2 && length == 0)
 124                     break;
 125             }
 126         } else {
 127             if (code == 1)
 128                 offset = bytestream2_get_byte(&g);
 129         }
 130
 131         /* Do boundary check */
 132         if (dst + (length << lentab[code]) > frame_end)
 133             break;
 134
 135         switch (code) {
 136         case 0:                // normal chain
 137             if (length >= bytestream2_get_bytes_left(&g)) {
 138                 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
 139                 return AVERROR_INVALIDDATA;
 140             }
 141             bytestream2_get_buffer(&g, dst, length);
 142             dst += length;
 143             break;
 144         case 1:                // back chain
 145             dst_offset = dst - offset;
 146             length    *= 4;     // Convert dwords to bytes.
 147             if (dst_offset < bfi->dst)
 148                 break;
 149             while (length--)
 150                 *dst++ = *dst_offset++;
 151             break;
 152         case 2:                // skip chain
 153             dst += length;
 154             break;
 155         case 3:                // fill chain
 156             colour1 = bytestream2_get_byte(&g);
 157             colour2 = bytestream2_get_byte(&g);
 158             while (length--) {
 159                 *dst++ = colour1;
 160                 *dst++ = colour2;
 161             }
 162             break;
 163         }
 164     }
 165
 166     src = bfi->dst;
 167     dst = frame->data[0];
 168     while (height--) {
 169         memcpy(dst, src, avctx->width);
 170         src += avctx->width;
 171         dst += frame->linesize[0];
 172     }
 173     *got_frame = 1;
 174
 175     return buf_size;
 176 }
 177
 178 static av_cold int bfi_decode_close(AVCodecContext *avctx)
 179 {
 180     BFIContext *bfi = avctx->priv_data;
 181     av_freep(&bfi->dst);
 182     return 0;
 183 }
 184
 185 const FFCodec ff_bfi_decoder = {
 186     .p.name         = "bfi",
 187     CODEC_LONG_NAME("Brute Force & Ignorance"),
 188     .p.type         = AVMEDIA_TYPE_VIDEO,
 189     .p.id           = AV_CODEC_ID_BFI,
 190     .priv_data_size = sizeof(BFIContext),
 191     .init           = bfi_decode_init,
 192     .close          = bfi_decode_close,
 193     FF_CODEC_DECODE_CB(bfi_decode_frame),
 194     .p.capabilities = AV_CODEC_CAP_DR1,
 195 };