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     uint8_t *dst;
  37 } BFIContext;
  38
  39 static av_cold int bfi_decode_init(AVCodecContext *avctx)
  40 {
  41     BFIContext *bfi = avctx->priv_data;
  42     avctx->pix_fmt  = AV_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 *got_frame, AVPacket *avpkt)
  49 {
  50     AVFrame *frame = data;
  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 ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
  61         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  62         return ret;
  63     }
  64
  65     bytestream2_init(&g, avpkt->data, buf_size);
  66
  67     /* Set frame parameters and palette, if necessary */
  68     if (!avctx->frame_number) {
  69         frame->pict_type = AV_PICTURE_TYPE_I;
  70         frame->key_frame = 1;
  71         /* Setting the palette */
  72         if (avctx->extradata_size > 768) {
  73             av_log(NULL, 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 = 0;
  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         frame->palette_has_changed = 1;
  86     } else {
  87         frame->pict_type = AV_PICTURE_TYPE_P;
  88         frame->key_frame = 0;
  89     }
  90
  91     bytestream2_skip(&g, 4); // Unpacked size, not required.
  92
  93     while (dst != frame_end) {
  94         static const uint8_t lentab[4] = { 0, 2, 0, 1 };
  95         unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);
  96         unsigned int code   = byte >> 6;
  97         unsigned int length = byte & ~0xC0;
  98
  99         if (!bytestream2_get_bytes_left(&g)) {
 100             av_log(avctx, AV_LOG_ERROR,
 101                    "Input resolution larger than actual frame.\n");
 102             return AVERROR_INVALIDDATA;
 103         }
 104
 105         /* Get length and offset (if required) */
 106         if (length == 0) {
 107             if (code == 1) {
 108                 length = bytestream2_get_byte(&g);
 109                 offset = bytestream2_get_le16(&g);
 110             } else {
 111                 length = bytestream2_get_le16(&g);
 112                 if (code == 2 && length == 0)
 113                     break;
 114             }
 115         } else {
 116             if (code == 1)
 117                 offset = bytestream2_get_byte(&g);
 118         }
 119
 120         /* Do boundary check */
 121         if (dst + (length << lentab[code]) > frame_end)
 122             break;
 123
 124         switch (code) {
 125         case 0:                // normal chain
 126             if (length >= bytestream2_get_bytes_left(&g)) {
 127                 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
 128                 return AVERROR_INVALIDDATA;
 129             }
 130             bytestream2_get_buffer(&g, dst, length);
 131             dst += length;
 132             break;
 133         case 1:                // back chain
 134             dst_offset = dst - offset;
 135             length    *= 4;     // Convert dwords to bytes.
 136             if (dst_offset < bfi->dst)
 137                 break;
 138             while (length--)
 139                 *dst++ = *dst_offset++;
 140             break;
 141         case 2:                // skip chain
 142             dst += length;
 143             break;
 144         case 3:                // fill chain
 145             colour1 = bytestream2_get_byte(&g);
 146             colour2 = bytestream2_get_byte(&g);
 147             while (length--) {
 148                 *dst++ = colour1;
 149                 *dst++ = colour2;
 150             }
 151             break;
 152         }
 153     }
 154
 155     src = bfi->dst;
 156     dst = frame->data[0];
 157     while (height--) {
 158         memcpy(dst, src, avctx->width);
 159         src += avctx->width;
 160         dst += frame->linesize[0];
 161     }
 162     *got_frame = 1;
 163
 164     return buf_size;
 165 }
 166
 167 static av_cold int bfi_decode_close(AVCodecContext *avctx)
 168 {
 169     BFIContext *bfi = avctx->priv_data;
 170     av_free(bfi->dst);
 171     return 0;
 172 }
 173
 174 AVCodec ff_bfi_decoder = {
 175     .name           = "bfi",
 176     .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
 177     .type           = AVMEDIA_TYPE_VIDEO,
 178     .id             = AV_CODEC_ID_BFI,
 179     .priv_data_size = sizeof(BFIContext),
 180     .init           = bfi_decode_init,
 181     .close          = bfi_decode_close,
 182     .decode         = bfi_decode_frame,
 183     .capabilities   = AV_CODEC_CAP_DR1,
 184     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 185 };