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  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/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.     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, void *data,
  51.                             int *got_frame, AVPacket *avpkt)
  52. {
  53.     AVFrame *frame = data;
  54.     GetByteContext g;
  55.     int buf_size    = avpkt->size;
  56.     BFIContext *bfi = avctx->priv_data;
  57.     uint8_t *dst    = bfi->dst;
  58.     uint8_t *src, *dst_offset, colour1, colour2;
  59.     uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
  60.     uint32_t *pal;
  61.     int i, j, ret, height = avctx->height;
  62.  
  63.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
  64.         return ret;
  65.  
  66.     bytestream2_init(&g, avpkt->data, buf_size);
  67.  
  68.     /* Set frame parameters and palette, if necessary */
  69.     if (!avctx->frame_number) {
  70.         frame->pict_type = AV_PICTURE_TYPE_I;
  71.         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 AVERROR_INVALIDDATA;
  76.         }
  77.         pal = (uint32_t *)frame->data[1];
  78.         for (i = 0; i < avctx->extradata_size / 3; i++) {
  79.             int shift = 16;
  80.             *pal = 0xFFU << 24;
  81.             for (j = 0; j < 3; j++, shift -= 8)
  82.                 *pal += ((avctx->extradata[i * 3 + j] << 2) |
  83.                          (avctx->extradata[i * 3 + j] >> 4)) << shift;
  84.             pal++;
  85.         }
  86.         memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));
  87.         frame->palette_has_changed = 1;
  88.     } else {
  89.         frame->pict_type = AV_PICTURE_TYPE_P;
  90.         frame->key_frame = 0;
  91.         frame->palette_has_changed = 0;
  92.         memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));
  93.     }
  94.  
  95.     bytestream2_skip(&g, 4); // Unpacked size, not required.
  96.  
  97.     while (dst != frame_end) {
  98.         static const uint8_t lentab[4] = { 0, 2, 0, 1 };
  99.         unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);
  100.         unsigned int code   = byte >> 6;
  101.         unsigned int length = byte & ~0xC0;
  102.  
  103.         if (!bytestream2_get_bytes_left(&g)) {
  104.             av_log(avctx, AV_LOG_ERROR,
  105.                    "Input resolution larger than actual frame.\n");
  106.             return AVERROR_INVALIDDATA;
  107.         }
  108.  
  109.         /* Get length and offset (if required) */
  110.         if (length == 0) {
  111.             if (code == 1) {
  112.                 length = bytestream2_get_byte(&g);
  113.                 offset = bytestream2_get_le16(&g);
  114.             } else {
  115.                 length = bytestream2_get_le16(&g);
  116.                 if (code == 2 && length == 0)
  117.                     break;
  118.             }
  119.         } else {
  120.             if (code == 1)
  121.                 offset = bytestream2_get_byte(&g);
  122.         }
  123.  
  124.         /* Do boundary check */
  125.         if (dst + (length << lentab[code]) > frame_end)
  126.             break;
  127.  
  128.         switch (code) {
  129.         case 0:                // normal chain
  130.             if (length >= bytestream2_get_bytes_left(&g)) {
  131.                 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
  132.                 return AVERROR_INVALIDDATA;
  133.             }
  134.             bytestream2_get_buffer(&g, dst, length);
  135.             dst += length;
  136.             break;
  137.         case 1:                // back chain
  138.             dst_offset = dst - offset;
  139.             length    *= 4;     // Convert dwords to bytes.
  140.             if (dst_offset < bfi->dst)
  141.                 break;
  142.             while (length--)
  143.                 *dst++ = *dst_offset++;
  144.             break;
  145.         case 2:                // skip chain
  146.             dst += length;
  147.             break;
  148.         case 3:                // fill chain
  149.             colour1 = bytestream2_get_byte(&g);
  150.             colour2 = bytestream2_get_byte(&g);
  151.             while (length--) {
  152.                 *dst++ = colour1;
  153.                 *dst++ = colour2;
  154.             }
  155.             break;
  156.         }
  157.     }
  158.  
  159.     src = bfi->dst;
  160.     dst = frame->data[0];
  161.     while (height--) {
  162.         memcpy(dst, src, avctx->width);
  163.         src += avctx->width;
  164.         dst += frame->linesize[0];
  165.     }
  166.     *got_frame = 1;
  167.  
  168.     return buf_size;
  169. }
  170.  
  171. static av_cold int bfi_decode_close(AVCodecContext *avctx)
  172. {
  173.     BFIContext *bfi = avctx->priv_data;
  174.     av_free(bfi->dst);
  175.     return 0;
  176. }
  177.  
  178. AVCodec ff_bfi_decoder = {
  179.     .name           = "bfi",
  180.     .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
  181.     .type           = AVMEDIA_TYPE_VIDEO,
  182.     .id             = AV_CODEC_ID_BFI,
  183.     .priv_data_size = sizeof(BFIContext),
  184.     .init           = bfi_decode_init,
  185.     .close          = bfi_decode_close,
  186.     .decode         = bfi_decode_frame,
  187.     .capabilities   = CODEC_CAP_DR1,
  188. };
  189.