libavcodec/bfi.c

   1 /*
   2  * Brute Force & Ignorance (BFI) video decoder
   3  * Copyright (c) 2008 Sisir Koppaka
   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  * @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/common.h"
  30 #include "avcodec.h"
  31 #include "bytestream.h"
  32 #include "internal.h"
  33
  34 typedef struct BFIContext {
  35     AVCodecContext *avctx;
  36     AVFrame frame;
  37     uint8_t *dst;
  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     return 0;
  46 }
  47
  48 static int bfi_decode_frame(AVCodecContext *avctx, void *data,
  49                             int *got_frame, AVPacket *avpkt)
  50 {
  51     GetByteContext g;
  52     int buf_size    = avpkt->size;
  53     BFIContext *bfi = avctx->priv_data;
  54     uint8_t *dst    = bfi->dst;
  55     uint8_t *src, *dst_offset, colour1, colour2;
  56     uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
  57     uint32_t *pal;
  58     int i, j, ret, height = avctx->height;
  59
  60     if (bfi->frame.data[0])
  61         avctx->release_buffer(avctx, &bfi->frame);
  62
  63     bfi->frame.reference = 1;
  64
  65     if ((ret = ff_get_buffer(avctx, &bfi->frame)) < 0) {
  66         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  67         return ret;
  68     }
  69
  70     bytestream2_init(&g, avpkt->data, buf_size);
  71
  72     /* Set frame parameters and palette, if necessary */
  73     if (!avctx->frame_number) {
  74         bfi->frame.pict_type = AV_PICTURE_TYPE_I;
  75         bfi->frame.key_frame = 1;
  76         /* Setting the palette */
  77         if (avctx->extradata_size > 768) {
  78             av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
  79             return AVERROR_INVALIDDATA;
  80         }
  81         pal = (uint32_t *)bfi->frame.data[1];
  82         for (i = 0; i < avctx->extradata_size / 3; i++) {
  83             int shift = 16;
  84             *pal = 0;
  85             for (j = 0; j < 3; j++, shift -= 8)
  86                 *pal += ((avctx->extradata[i * 3 + j] << 2) |
  87                          (avctx->extradata[i * 3 + j] >> 4)) << shift;
  88             pal++;
  89         }
  90         bfi->frame.palette_has_changed = 1;
  91     } else {
  92         bfi->frame.pict_type = AV_PICTURE_TYPE_P;
  93         bfi->frame.key_frame = 0;
  94     }
  95
  96     bytestream2_skip(&g, 4); // Unpacked size, not required.
  97
  98     while (dst != frame_end) {
  99         static const uint8_t lentab[4] = { 0, 2, 0, 1 };
 100         unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);
 101         unsigned int code   = byte >> 6;
 102         unsigned int length = byte & ~0xC0;
 103
 104         if (!bytestream2_get_bytes_left(&g)) {
 105             av_log(avctx, AV_LOG_ERROR,
 106                    "Input resolution larger than actual frame.\n");
 107             return AVERROR_INVALIDDATA;
 108         }
 109
 110         /* Get length and offset (if required) */
 111         if (length == 0) {
 112             if (code == 1) {
 113                 length = bytestream2_get_byte(&g);
 114                 offset = bytestream2_get_le16(&g);
 115             } else {
 116                 length = bytestream2_get_le16(&g);
 117                 if (code == 2 && length == 0)
 118                     break;
 119             }
 120         } else {
 121             if (code == 1)
 122                 offset = bytestream2_get_byte(&g);
 123         }
 124
 125         /* Do boundary check */
 126         if (dst + (length << lentab[code]) > frame_end)
 127             break;
 128
 129         switch (code) {
 130         case 0:                // normal chain
 131             if (length >= bytestream2_get_bytes_left(&g)) {
 132                 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
 133                 return AVERROR_INVALIDDATA;
 134             }
 135             bytestream2_get_buffer(&g, dst, length);
 136             dst += length;
 137             break;
 138         case 1:                // back chain
 139             dst_offset = dst - offset;
 140             length    *= 4;     // Convert dwords to bytes.
 141             if (dst_offset < bfi->dst)
 142                 break;
 143             while (length--)
 144                 *dst++ = *dst_offset++;
 145             break;
 146         case 2:                // skip chain
 147             dst += length;
 148             break;
 149         case 3:                // fill chain
 150             colour1 = bytestream2_get_byte(&g);
 151             colour2 = bytestream2_get_byte(&g);
 152             while (length--) {
 153                 *dst++ = colour1;
 154                 *dst++ = colour2;
 155             }
 156             break;
 157         }
 158     }
 159
 160     src = bfi->dst;
 161     dst = bfi->frame.data[0];
 162     while (height--) {
 163         memcpy(dst, src, avctx->width);
 164         src += avctx->width;
 165         dst += bfi->frame.linesize[0];
 166     }
 167     *got_frame = 1;
 168     *(AVFrame *)data = bfi->frame;
 169     return buf_size;
 170 }
 171
 172 static av_cold int bfi_decode_close(AVCodecContext *avctx)
 173 {
 174     BFIContext *bfi = avctx->priv_data;
 175     if (bfi->frame.data[0])
 176         avctx->release_buffer(avctx, &bfi->frame);
 177     av_free(bfi->dst);
 178     return 0;
 179 }
 180
 181 AVCodec ff_bfi_decoder = {
 182     .name           = "bfi",
 183     .type           = AVMEDIA_TYPE_VIDEO,
 184     .id             = AV_CODEC_ID_BFI,
 185     .priv_data_size = sizeof(BFIContext),
 186     .init           = bfi_decode_init,
 187     .close          = bfi_decode_close,
 188     .decode         = bfi_decode_frame,
 189     .capabilities   = CODEC_CAP_DR1,
 190     .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
 191 };