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 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 
29 #include "libavutil/common.h"
30 #include "avcodec.h"
31 #include "bytestream.h"
32 #include "internal.h"
33 
34 typedef struct BFIContext {
38 } BFIContext;
39 
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 {
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, 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 (ff_get_buffer(avctx, &bfi->frame) < 0) {
66  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
67  return -1;
68  }
69 
70  bytestream2_init(&g, avpkt->data, buf_size);
71 
72  /* Set frame parameters and palette, if necessary */
73  if (!avctx->frame_number) {
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 -1;
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 {
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 -1;
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 -1;
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 
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 
182  .name = "bfi",
183  .type = AVMEDIA_TYPE_VIDEO,
184  .id = AV_CODEC_ID_BFI,
185  .priv_data_size = sizeof(BFIContext),
189  .capabilities = CODEC_CAP_DR1,
190  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
191 };