1 /*
2 * Tiertex Limited SEQ Video Decoder
3 * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.net)
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 * Tiertex Limited SEQ video decoder
25 */
26
27 #define BITSTREAM_READER_LE
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "internal.h"
31
32
33 typedef struct SeqVideoContext {
34 AVCodecContext *avctx;
35 AVFrame *frame;
36 } SeqVideoContext;
37
38
seq_unpack_rle_block(const unsigned char * src,const unsigned char * src_end,unsigned char * dst,int dst_size)39 static const unsigned char *seq_unpack_rle_block(const unsigned char *src,
40 const unsigned char *src_end,
41 unsigned char *dst, int dst_size)
42 {
43 int i, len, sz;
44 GetBitContext gb;
45 int code_table[64];
46
47 /* get the rle codes */
48 init_get_bits(&gb, src, (src_end - src) * 8);
49 for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
50 if (get_bits_left(&gb) < 4)
51 return NULL;
52 code_table[i] = get_sbits(&gb, 4);
53 sz += FFABS(code_table[i]);
54 }
55 src += (get_bits_count(&gb) + 7) / 8;
56
57 /* do the rle unpacking */
58 for (i = 0; i < 64 && dst_size > 0; i++) {
59 len = code_table[i];
60 if (len < 0) {
61 len = -len;
62 if (src_end - src < 1)
63 return NULL;
64 memset(dst, *src++, FFMIN(len, dst_size));
65 } else {
66 if (src_end - src < len)
67 return NULL;
68 memcpy(dst, src, FFMIN(len, dst_size));
69 src += len;
70 }
71 dst += len;
72 dst_size -= len;
73 }
74 return src;
75 }
76
seq_decode_op1(SeqVideoContext * seq,const unsigned char * src,const unsigned char * src_end,unsigned char * dst)77 static const unsigned char *seq_decode_op1(SeqVideoContext *seq,
78 const unsigned char *src,
79 const unsigned char *src_end,
80 unsigned char *dst)
81 {
82 const unsigned char *color_table;
83 int b, i, len, bits;
84 GetBitContext gb;
85 unsigned char block[8 * 8];
86
87 if (src_end - src < 1)
88 return NULL;
89 len = *src++;
90 if (len & 0x80) {
91 switch (len & 3) {
92 case 1:
93 src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
94 for (b = 0; b < 8; b++) {
95 memcpy(dst, &block[b * 8], 8);
96 dst += seq->frame->linesize[0];
97 }
98 break;
99 case 2:
100 src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
101 for (i = 0; i < 8; i++) {
102 for (b = 0; b < 8; b++)
103 dst[b * seq->frame->linesize[0]] = block[i * 8 + b];
104 ++dst;
105 }
106 break;
107 }
108 } else {
109 if (len <= 0)
110 return NULL;
111 bits = ff_log2_tab[len - 1] + 1;
112 if (src_end - src < len + 8 * bits)
113 return NULL;
114 color_table = src;
115 src += len;
116 init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
117 for (b = 0; b < 8; b++) {
118 for (i = 0; i < 8; i++)
119 dst[i] = color_table[get_bits(&gb, bits)];
120 dst += seq->frame->linesize[0];
121 }
122 }
123
124 return src;
125 }
126
seq_decode_op2(SeqVideoContext * seq,const unsigned char * src,const unsigned char * src_end,unsigned char * dst)127 static const unsigned char *seq_decode_op2(SeqVideoContext *seq,
128 const unsigned char *src,
129 const unsigned char *src_end,
130 unsigned char *dst)
131 {
132 int i;
133
134 if (src_end - src < 8 * 8)
135 return NULL;
136
137 for (i = 0; i < 8; i++) {
138 memcpy(dst, src, 8);
139 src += 8;
140 dst += seq->frame->linesize[0];
141 }
142
143 return src;
144 }
145
seq_decode_op3(SeqVideoContext * seq,const unsigned char * src,const unsigned char * src_end,unsigned char * dst)146 static const unsigned char *seq_decode_op3(SeqVideoContext *seq,
147 const unsigned char *src,
148 const unsigned char *src_end,
149 unsigned char *dst)
150 {
151 int pos, offset;
152
153 do {
154 if (src_end - src < 2)
155 return NULL;
156 pos = *src++;
157 offset = ((pos >> 3) & 7) * seq->frame->linesize[0] + (pos & 7);
158 dst[offset] = *src++;
159 } while (!(pos & 0x80));
160
161 return src;
162 }
163
seqvideo_decode(SeqVideoContext * seq,const unsigned char * data,int data_size)164 static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
165 {
166 const unsigned char *data_end = data + data_size;
167 GetBitContext gb;
168 int flags, i, j, x, y, op;
169 unsigned char c[3];
170 unsigned char *dst;
171 uint32_t *palette;
172
173 flags = *data++;
174
175 if (flags & 1) {
176 palette = (uint32_t *)seq->frame->data[1];
177 if (data_end - data < 256 * 3)
178 return AVERROR_INVALIDDATA;
179 for (i = 0; i < 256; i++) {
180 for (j = 0; j < 3; j++, data++)
181 c[j] = (*data << 2) | (*data >> 4);
182 palette[i] = 0xFFU << 24 | AV_RB24(c);
183 }
184 seq->frame->palette_has_changed = 1;
185 }
186
187 if (flags & 2) {
188 if (data_end - data < 128)
189 return AVERROR_INVALIDDATA;
190 init_get_bits(&gb, data, 128 * 8); data += 128;
191 for (y = 0; y < 128; y += 8)
192 for (x = 0; x < 256; x += 8) {
193 dst = &seq->frame->data[0][y * seq->frame->linesize[0] + x];
194 op = get_bits(&gb, 2);
195 switch (op) {
196 case 1:
197 data = seq_decode_op1(seq, data, data_end, dst);
198 break;
199 case 2:
200 data = seq_decode_op2(seq, data, data_end, dst);
201 break;
202 case 3:
203 data = seq_decode_op3(seq, data, data_end, dst);
204 break;
205 }
206 if (!data)
207 return AVERROR_INVALIDDATA;
208 }
209 }
210 return 0;
211 }
212
seqvideo_decode_init(AVCodecContext * avctx)213 static av_cold int seqvideo_decode_init(AVCodecContext *avctx)
214 {
215 SeqVideoContext *seq = avctx->priv_data;
216 int ret;
217
218 seq->avctx = avctx;
219 avctx->pix_fmt = AV_PIX_FMT_PAL8;
220
221 ret = ff_set_dimensions(avctx, 256, 128);
222 if (ret < 0)
223 return ret;
224
225 seq->frame = av_frame_alloc();
226 if (!seq->frame)
227 return AVERROR(ENOMEM);
228
229 return 0;
230 }
231
seqvideo_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)232 static int seqvideo_decode_frame(AVCodecContext *avctx,
233 void *data, int *got_frame,
234 AVPacket *avpkt)
235 {
236 const uint8_t *buf = avpkt->data;
237 int buf_size = avpkt->size;
238 int ret;
239
240 SeqVideoContext *seq = avctx->priv_data;
241
242 if ((ret = ff_reget_buffer(avctx, seq->frame, 0)) < 0)
243 return ret;
244
245 if (seqvideo_decode(seq, buf, buf_size))
246 return AVERROR_INVALIDDATA;
247
248 if ((ret = av_frame_ref(data, seq->frame)) < 0)
249 return ret;
250 *got_frame = 1;
251
252 return buf_size;
253 }
254
seqvideo_decode_end(AVCodecContext * avctx)255 static av_cold int seqvideo_decode_end(AVCodecContext *avctx)
256 {
257 SeqVideoContext *seq = avctx->priv_data;
258
259 av_frame_free(&seq->frame);
260
261 return 0;
262 }
263
264 AVCodec ff_tiertexseqvideo_decoder = {
265 .name = "tiertexseqvideo",
266 .long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
267 .type = AVMEDIA_TYPE_VIDEO,
268 .id = AV_CODEC_ID_TIERTEXSEQVIDEO,
269 .priv_data_size = sizeof(SeqVideoContext),
270 .init = seqvideo_decode_init,
271 .close = seqvideo_decode_end,
272 .decode = seqvideo_decode_frame,
273 .capabilities = AV_CODEC_CAP_DR1,
274 };
275