1 /*
2 * Interplay C93 video decoder
3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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 #include "avcodec.h"
23 #include "bytestream.h"
24 #include "codec_internal.h"
25 #include "internal.h"
26
27 typedef struct C93DecoderContext {
28 AVFrame *pictures[2];
29 int currentpic;
30 } C93DecoderContext;
31
32 typedef enum {
33 C93_8X8_FROM_PREV = 0x02,
34 C93_4X4_FROM_PREV = 0x06,
35 C93_4X4_FROM_CURR = 0x07,
36 C93_8X8_2COLOR = 0x08,
37 C93_4X4_2COLOR = 0x0A,
38 C93_4X4_4COLOR_GRP = 0x0B,
39 C93_4X4_4COLOR = 0x0D,
40 C93_NOOP = 0x0E,
41 C93_8X8_INTRA = 0x0F,
42 } C93BlockType;
43
44 #define WIDTH 320
45 #define HEIGHT 192
46
47 #define C93_HAS_PALETTE 0x01
48 #define C93_FIRST_FRAME 0x02
49
decode_end(AVCodecContext * avctx)50 static av_cold int decode_end(AVCodecContext *avctx)
51 {
52 C93DecoderContext * const c93 = avctx->priv_data;
53
54 av_frame_free(&c93->pictures[0]);
55 av_frame_free(&c93->pictures[1]);
56
57 return 0;
58 }
59
decode_init(AVCodecContext * avctx)60 static av_cold int decode_init(AVCodecContext *avctx)
61 {
62 C93DecoderContext *s = avctx->priv_data;
63 avctx->pix_fmt = AV_PIX_FMT_PAL8;
64
65 s->pictures[0] = av_frame_alloc();
66 s->pictures[1] = av_frame_alloc();
67 if (!s->pictures[0] || !s->pictures[1])
68 return AVERROR(ENOMEM);
69
70 return 0;
71 }
72
copy_block(AVCodecContext * avctx,uint8_t * to,uint8_t * from,int offset,int height,int stride)73 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
74 uint8_t *from, int offset, int height, int stride)
75 {
76 int i;
77 int width = height;
78 int from_x = offset % WIDTH;
79 int from_y = offset / WIDTH;
80 int overflow = from_x + width - WIDTH;
81
82 if (!from) {
83 /* silently ignoring predictive blocks in first frame */
84 return 0;
85 }
86
87 if (from_y + height > HEIGHT) {
88 av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
89 offset);
90 return AVERROR_INVALIDDATA;
91 }
92
93 if (overflow > 0) {
94 width -= overflow;
95 for (i = 0; i < height; i++) {
96 memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
97 }
98 }
99
100 for (i = 0; i < height; i++) {
101 memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
102 }
103
104 return 0;
105 }
106
draw_n_color(uint8_t * out,int stride,int width,int height,int bpp,uint8_t cols[4],uint8_t grps[4],uint32_t col)107 static inline void draw_n_color(uint8_t *out, int stride, int width,
108 int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
109 {
110 int x, y;
111 for (y = 0; y < height; y++) {
112 if (grps)
113 cols[0] = grps[3 * (y >> 1)];
114 for (x = 0; x < width; x++) {
115 if (grps)
116 cols[1]= grps[(x >> 1) + 1];
117 out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
118 col >>= bpp;
119 }
120 }
121 }
122
decode_frame(AVCodecContext * avctx,AVFrame * rframe,int * got_frame,AVPacket * avpkt)123 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
124 int *got_frame, AVPacket *avpkt)
125 {
126 const uint8_t *buf = avpkt->data;
127 int buf_size = avpkt->size;
128 C93DecoderContext * const c93 = avctx->priv_data;
129 AVFrame * const newpic = c93->pictures[c93->currentpic];
130 AVFrame * const oldpic = c93->pictures[c93->currentpic^1];
131 GetByteContext gb;
132 uint8_t *out;
133 int stride, ret, i, x, y, b, bt = 0;
134
135 if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0)
136 return ret;
137
138 c93->currentpic ^= 1;
139
140 if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0)
141 return ret;
142
143 stride = newpic->linesize[0];
144
145 bytestream2_init(&gb, buf, buf_size);
146 b = bytestream2_get_byte(&gb);
147 if (b & C93_FIRST_FRAME) {
148 newpic->pict_type = AV_PICTURE_TYPE_I;
149 newpic->key_frame = 1;
150 } else {
151 newpic->pict_type = AV_PICTURE_TYPE_P;
152 newpic->key_frame = 0;
153 }
154
155 for (y = 0; y < HEIGHT; y += 8) {
156 out = newpic->data[0] + y * stride;
157 for (x = 0; x < WIDTH; x += 8) {
158 uint8_t *copy_from = oldpic->data[0];
159 unsigned int offset, j;
160 uint8_t cols[4], grps[4];
161 C93BlockType block_type;
162
163 if (!bt)
164 bt = bytestream2_get_byte(&gb);
165
166 block_type= bt & 0x0F;
167 switch (block_type) {
168 case C93_8X8_FROM_PREV:
169 offset = bytestream2_get_le16(&gb);
170 if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
171 return ret;
172 break;
173
174 case C93_4X4_FROM_CURR:
175 copy_from = newpic->data[0];
176 case C93_4X4_FROM_PREV:
177 for (j = 0; j < 8; j += 4) {
178 for (i = 0; i < 8; i += 4) {
179 int offset = bytestream2_get_le16(&gb);
180 int from_x = offset % WIDTH;
181 int from_y = offset / WIDTH;
182 if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
183 (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
184 avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j);
185 return AVERROR_INVALIDDATA;
186 }
187 if ((ret = copy_block(avctx, &out[j*stride+i],
188 copy_from, offset, 4, stride)) < 0)
189 return ret;
190 }
191 }
192 break;
193
194 case C93_8X8_2COLOR:
195 bytestream2_get_buffer(&gb, cols, 2);
196 for (i = 0; i < 8; i++) {
197 draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
198 NULL, bytestream2_get_byte(&gb));
199 }
200
201 break;
202
203 case C93_4X4_2COLOR:
204 case C93_4X4_4COLOR:
205 case C93_4X4_4COLOR_GRP:
206 for (j = 0; j < 8; j += 4) {
207 for (i = 0; i < 8; i += 4) {
208 if (block_type == C93_4X4_2COLOR) {
209 bytestream2_get_buffer(&gb, cols, 2);
210 draw_n_color(out + i + j*stride, stride, 4, 4,
211 1, cols, NULL, bytestream2_get_le16(&gb));
212 } else if (block_type == C93_4X4_4COLOR) {
213 bytestream2_get_buffer(&gb, cols, 4);
214 draw_n_color(out + i + j*stride, stride, 4, 4,
215 2, cols, NULL, bytestream2_get_le32(&gb));
216 } else {
217 bytestream2_get_buffer(&gb, grps, 4);
218 draw_n_color(out + i + j*stride, stride, 4, 4,
219 1, cols, grps, bytestream2_get_le16(&gb));
220 }
221 }
222 }
223 break;
224
225 case C93_NOOP:
226 break;
227
228 case C93_8X8_INTRA:
229 for (j = 0; j < 8; j++)
230 bytestream2_get_buffer(&gb, out + j*stride, 8);
231 break;
232
233 default:
234 av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
235 block_type, x, y);
236 return AVERROR_INVALIDDATA;
237 }
238 bt >>= 4;
239 out += 8;
240 }
241 }
242
243 if (b & C93_HAS_PALETTE) {
244 uint32_t *palette = (uint32_t *) newpic->data[1];
245 for (i = 0; i < 256; i++) {
246 palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
247 }
248 newpic->palette_has_changed = 1;
249 } else {
250 if (oldpic->data[1])
251 memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
252 }
253
254 if ((ret = av_frame_ref(rframe, newpic)) < 0)
255 return ret;
256 *got_frame = 1;
257
258 return buf_size;
259 }
260
261 const FFCodec ff_c93_decoder = {
262 .p.name = "c93",
263 .p.long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
264 .p.type = AVMEDIA_TYPE_VIDEO,
265 .p.id = AV_CODEC_ID_C93,
266 .priv_data_size = sizeof(C93DecoderContext),
267 .init = decode_init,
268 .close = decode_end,
269 FF_CODEC_DECODE_CB(decode_frame),
270 .p.capabilities = AV_CODEC_CAP_DR1,
271 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
272 };
273