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 bfi.c
  24  * @brief Brute Force & Ignorance (.bfi) video decoder
  25  * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
  26  * @sa http://wiki.multimedia.cx/index.php?title=BFI
  27  */
  28
  29 #include "libavutil/common.h"
  30 #include "avcodec.h"
  31 #include "bytestream.h"
  32
  33 typedef struct BFIContext {
  34     AVCodecContext *avctx;
  35     AVFrame frame;
  36     uint8_t *dst;
  37 } BFIContext;
  38
  39 static int bfi_decode_init(AVCodecContext * avctx)
  40 {
  41     BFIContext *bfi = avctx->priv_data;
  42     avctx->pix_fmt = PIX_FMT_PAL8;
  43     bfi->dst = av_mallocz(avctx->width * avctx->height);
  44     return 0;
  45 }
  46
  47 static int bfi_decode_frame(AVCodecContext * avctx, void *data,
  48                             int *data_size, const uint8_t * buf,
  49                             int buf_size)
  50 {
  51     BFIContext *bfi = avctx->priv_data;
  52     uint8_t *dst = bfi->dst;
  53     uint8_t *src, *dst_offset, colour1, colour2;
  54     uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
  55     uint32_t *pal;
  56     int i, j, height = avctx->height;
  57
  58     if (bfi->frame.data[0])
  59         avctx->release_buffer(avctx, &bfi->frame);
  60
  61     bfi->frame.reference = 1;
  62
  63     if (avctx->get_buffer(avctx, &bfi->frame) < 0) {
  64         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  65         return -1;
  66     }
  67
  68     /* Set frame parameters and palette, if necessary */
  69     if (!avctx->frame_number) {
  70         bfi->frame.pict_type = FF_I_TYPE;
  71         bfi->frame.key_frame = 1;
  72         /* Setting the palette */
  73         if(avctx->extradata_size>768) {
  74             av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
  75             return -1;
  76         }
  77         pal = (uint32_t *) bfi->frame.data[1];
  78         for (i = 0; i < avctx->extradata_size / 3; i++) {
  79             int shift = 16;
  80             *pal = 0;
  81             for (j = 0; j < 3; j++, shift -= 8)
  82                 *pal +=
  83                     ((avctx->extradata[i * 3 + j] << 2) |
  84                     (avctx->extradata[i * 3 + j] >> 4)) << shift;
  85             pal++;
  86         }
  87         bfi->frame.palette_has_changed = 1;
  88     } else {
  89         bfi->frame.pict_type = FF_P_TYPE;
  90         bfi->frame.key_frame = 0;
  91     }
  92
  93     buf += 4; //Unpacked size, not required.
  94
  95     while (dst != frame_end) {
  96         static const uint8_t lentab[4]={0,2,0,1};
  97         unsigned int byte = *buf++, offset;
  98         unsigned int code = byte >> 6;
  99         unsigned int length = byte & ~0xC0;
 100
 101         /* Get length and offset(if required) */
 102         if (length == 0) {
 103             if (code == 1) {
 104                 length = bytestream_get_byte(&buf);
 105                 offset = bytestream_get_le16(&buf);
 106             } else {
 107                 length = bytestream_get_le16(&buf);
 108                 if (code == 2 && length == 0)
 109                     break;
 110             }
 111         } else {
 112             if (code == 1)
 113                 offset = bytestream_get_byte(&buf);
 114         }
 115
 116         /* Do boundary check */
 117         if (dst + (length<<lentab[code]) > frame_end)
 118             break;
 119
 120         switch (code) {
 121
 122         case 0:                //Normal Chain
 123             bytestream_get_buffer(&buf, dst, length);
 124             dst += length;
 125             break;
 126
 127         case 1:                //Back Chain
 128             dst_offset = dst - offset;
 129             length *= 4;        //Convert dwords to bytes.
 130             if (dst_offset < bfi->dst)
 131                 break;
 132             while (length--)
 133                 *dst++ = *dst_offset++;
 134             break;
 135
 136         case 2:                //Skip Chain
 137             dst += length;
 138             break;
 139
 140         case 3:                //Fill Chain
 141             colour1 = bytestream_get_byte(&buf);
 142             colour2 = bytestream_get_byte(&buf);
 143             while (length--) {
 144                 *dst++ = colour1;
 145                 *dst++ = colour2;
 146             }
 147             break;
 148
 149         }
 150     }
 151
 152     src = bfi->dst;
 153     dst = bfi->frame.data[0];
 154     while (height--) {
 155         memcpy(dst, src, avctx->width);
 156         src += avctx->width;
 157         dst += bfi->frame.linesize[0];
 158     }
 159     *data_size = sizeof(AVFrame);
 160     *(AVFrame *) data = bfi->frame;
 161     return buf_size;
 162 }
 163
 164 static int bfi_decode_close(AVCodecContext * avctx)
 165 {
 166     BFIContext *bfi = avctx->priv_data;
 167     if (bfi->frame.data[0])
 168         avctx->release_buffer(avctx, &bfi->frame);
 169     av_free(bfi->dst);
 170     return 0;
 171 }
 172
 173 AVCodec bfi_decoder = {
 174     .name = "bfi",
 175     .type = CODEC_TYPE_VIDEO,
 176     .id = CODEC_ID_BFI,
 177     .priv_data_size = sizeof(BFIContext),
 178     .init = bfi_decode_init,
 179     .close = bfi_decode_close,
 180     .decode = bfi_decode_frame,
 181     .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
 182 };