Libav
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 {
37 } BFIContext;
38 
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;
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) {
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 {
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 
168 {
169  BFIContext *bfi = avctx->priv_data;
170  av_free(bfi->dst);
171  return 0;
172 }
173 
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),
183  .capabilities = CODEC_CAP_DR1,
184 };