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 
33 typedef struct BFIContext {
36  uint8_t *dst;
37 } BFIContext;
38 
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, AVPacket *avpkt)
49 {
51  int buf_size = avpkt->size;
52  BFIContext *bfi = avctx->priv_data;
53  uint8_t *dst = bfi->dst;
54  uint8_t *src, *dst_offset, colour1, colour2;
55  uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
56  uint32_t *pal;
57  int i, j, height = avctx->height;
58 
59  if (bfi->frame.data[0])
60  avctx->release_buffer(avctx, &bfi->frame);
61 
62  bfi->frame.reference = 1;
63 
64  if (avctx->get_buffer(avctx, &bfi->frame) < 0) {
65  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
66  return -1;
67  }
68 
69  bytestream2_init(&g, avpkt->data, buf_size);
70 
71  /* Set frame parameters and palette, if necessary */
72  if (!avctx->frame_number) {
74  bfi->frame.key_frame = 1;
75  /* Setting the palette */
76  if (avctx->extradata_size > 768) {
77  av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
78  return -1;
79  }
80  pal = (uint32_t *)bfi->frame.data[1];
81  for (i = 0; i < avctx->extradata_size / 3; i++) {
82  int shift = 16;
83  *pal = 0;
84  for (j = 0; j < 3; j++, shift -= 8)
85  *pal +=
86  ((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 
131  case 0: //Normal Chain
132  if (length >= bytestream2_get_bytes_left(&g)) {
133  av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
134  return -1;
135  }
136  bytestream2_get_buffer(&g, dst, length);
137  dst += length;
138  break;
139 
140  case 1: //Back Chain
141  dst_offset = dst - offset;
142  length *= 4; //Convert dwords to bytes.
143  if (dst_offset < bfi->dst)
144  break;
145  while (length--)
146  *dst++ = *dst_offset++;
147  break;
148 
149  case 2: //Skip Chain
150  dst += length;
151  break;
152 
153  case 3: //Fill Chain
154  colour1 = bytestream2_get_byte(&g);
155  colour2 = bytestream2_get_byte(&g);
156  while (length--) {
157  *dst++ = colour1;
158  *dst++ = colour2;
159  }
160  break;
161 
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  *data_size = sizeof(AVFrame);
173  *(AVFrame *)data = bfi->frame;
174  return buf_size;
175 }
176 
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 
187  .name = "bfi",
188  .type = AVMEDIA_TYPE_VIDEO,
189  .id = CODEC_ID_BFI,
190  .priv_data_size = sizeof(BFIContext),
194  .capabilities = CODEC_CAP_DR1,
195  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
196 };