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bfi.c
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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  AVFrame frame;
37  uint8_t *dst;
38  uint32_t pal[256];
39 } BFIContext;
40 
41 static av_cold int bfi_decode_init(AVCodecContext *avctx)
42 {
43  BFIContext *bfi = avctx->priv_data;
44  avctx->pix_fmt = AV_PIX_FMT_PAL8;
45  avcodec_get_frame_defaults(&bfi->frame);
46  bfi->dst = av_mallocz(avctx->width * avctx->height);
47  return 0;
48 }
49 
50 static int bfi_decode_frame(AVCodecContext *avctx, void *data,
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 (bfi->frame.data[0])
63  avctx->release_buffer(avctx, &bfi->frame);
64 
65  bfi->frame.reference = 3;
66 
67  if ((ret = ff_get_buffer(avctx, &bfi->frame)) < 0) {
68  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
69  return ret;
70  }
71 
72  bytestream2_init(&g, avpkt->data, buf_size);
73 
74  /* Set frame parameters and palette, if necessary */
75  if (!avctx->frame_number) {
76  bfi->frame.pict_type = AV_PICTURE_TYPE_I;
77  bfi->frame.key_frame = 1;
78  /* Setting the palette */
79  if (avctx->extradata_size > 768) {
80  av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
81  return AVERROR_INVALIDDATA;
82  }
83  pal = (uint32_t *)bfi->frame.data[1];
84  for (i = 0; i < avctx->extradata_size / 3; i++) {
85  int shift = 16;
86  *pal = 0xFFU << 24;
87  for (j = 0; j < 3; j++, shift -= 8)
88  *pal += ((avctx->extradata[i * 3 + j] << 2) |
89  (avctx->extradata[i * 3 + j] >> 4)) << shift;
90  pal++;
91  }
92  memcpy(bfi->pal, bfi->frame.data[1], sizeof(bfi->pal));
93  bfi->frame.palette_has_changed = 1;
94  } else {
95  bfi->frame.pict_type = AV_PICTURE_TYPE_P;
96  bfi->frame.key_frame = 0;
97  bfi->frame.palette_has_changed = 0;
98  memcpy(bfi->frame.data[1], bfi->pal, sizeof(bfi->pal));
99  }
100 
101  bytestream2_skip(&g, 4); // Unpacked size, not required.
102 
103  while (dst != frame_end) {
104  static const uint8_t lentab[4] = { 0, 2, 0, 1 };
105  unsigned int byte = bytestream2_get_byte(&g), av_uninit(offset);
106  unsigned int code = byte >> 6;
107  unsigned int length = byte & ~0xC0;
108 
109  if (!bytestream2_get_bytes_left(&g)) {
110  av_log(avctx, AV_LOG_ERROR,
111  "Input resolution larger than actual frame.\n");
112  return AVERROR_INVALIDDATA;
113  }
114 
115  /* Get length and offset (if required) */
116  if (length == 0) {
117  if (code == 1) {
118  length = bytestream2_get_byte(&g);
119  offset = bytestream2_get_le16(&g);
120  } else {
121  length = bytestream2_get_le16(&g);
122  if (code == 2 && length == 0)
123  break;
124  }
125  } else {
126  if (code == 1)
127  offset = bytestream2_get_byte(&g);
128  }
129 
130  /* Do boundary check */
131  if (dst + (length << lentab[code]) > frame_end)
132  break;
133 
134  switch (code) {
135  case 0: // normal chain
136  if (length >= bytestream2_get_bytes_left(&g)) {
137  av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
138  return AVERROR_INVALIDDATA;
139  }
140  bytestream2_get_buffer(&g, dst, length);
141  dst += length;
142  break;
143  case 1: // back chain
144  dst_offset = dst - offset;
145  length *= 4; // Convert dwords to bytes.
146  if (dst_offset < bfi->dst)
147  break;
148  while (length--)
149  *dst++ = *dst_offset++;
150  break;
151  case 2: // skip chain
152  dst += length;
153  break;
154  case 3: // fill chain
155  colour1 = bytestream2_get_byte(&g);
156  colour2 = bytestream2_get_byte(&g);
157  while (length--) {
158  *dst++ = colour1;
159  *dst++ = colour2;
160  }
161  break;
162  }
163  }
164 
165  src = bfi->dst;
166  dst = bfi->frame.data[0];
167  while (height--) {
168  memcpy(dst, src, avctx->width);
169  src += avctx->width;
170  dst += bfi->frame.linesize[0];
171  }
172  *got_frame = 1;
173  *(AVFrame *)data = bfi->frame;
174  return buf_size;
175 }
176 
177 static av_cold int bfi_decode_close(AVCodecContext *avctx)
178 {
179  BFIContext *bfi = avctx->priv_data;
180  if (bfi->frame.data[0])
181  avctx->release_buffer(avctx, &bfi->frame);
182  av_free(bfi->dst);
183  return 0;
184 }
185 
186 AVCodec ff_bfi_decoder = {
187  .name = "bfi",
188  .type = AVMEDIA_TYPE_VIDEO,
189  .id = AV_CODEC_ID_BFI,
190  .priv_data_size = sizeof(BFIContext),
191  .init = bfi_decode_init,
192  .close = bfi_decode_close,
193  .decode = bfi_decode_frame,
194  .capabilities = CODEC_CAP_DR1,
195  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
196 };
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