789d7e798b9dbf3698cc07047d5b27201e2cf102
[libav.git] / libavcodec / msvideo1.c
1 /*
2 * Microsoft Video-1 Decoder
3 * Copyright (C) 2003 the ffmpeg project
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 */
20
21 /**
22 * @file msvideo1.c
23 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
24 * For more information about the MS Video-1 format, visit:
25 * http://www.pcisys.net/~melanson/codecs/
26 *
27 * This decoder outputs either PAL8 or RGB555 data, depending on the
28 * whether a RGB palette was passed through palctrl;
29 * if it's present, then the data is PAL8; RGB555 otherwise.
30 */
31
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <unistd.h>
36
37 #include "common.h"
38 #include "avcodec.h"
39 #include "dsputil.h"
40
41 #define PALETTE_COUNT 256
42 #define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
43 #define CHECK_STREAM_PTR(n) \
44 if ((stream_ptr + n) > s->size ) { \
45 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
46 stream_ptr + n, s->size); \
47 return; \
48 }
49
50 typedef struct Msvideo1Context {
51
52 AVCodecContext *avctx;
53 DSPContext dsp;
54 AVFrame frame;
55
56 unsigned char *buf;
57 int size;
58
59 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
60
61 } Msvideo1Context;
62
63 static int msvideo1_decode_init(AVCodecContext *avctx)
64 {
65 Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
66
67 s->avctx = avctx;
68
69 /* figure out the colorspace based on the presence of a palette */
70 if (s->avctx->palctrl) {
71 s->mode_8bit = 1;
72 avctx->pix_fmt = PIX_FMT_PAL8;
73 } else {
74 s->mode_8bit = 0;
75 avctx->pix_fmt = PIX_FMT_RGB555;
76 }
77
78 avctx->has_b_frames = 0;
79 dsputil_init(&s->dsp, avctx);
80
81 s->frame.data[0] = NULL;
82
83 return 0;
84 }
85
86 static void msvideo1_decode_8bit(Msvideo1Context *s)
87 {
88 int block_ptr, pixel_ptr;
89 int total_blocks;
90 int pixel_x, pixel_y; /* pixel width and height iterators */
91 int block_x, block_y; /* block width and height iterators */
92 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
93 int block_inc;
94 int row_dec;
95
96 /* decoding parameters */
97 int stream_ptr;
98 unsigned char byte_a, byte_b;
99 unsigned short flags;
100 int skip_blocks;
101 unsigned char colors[8];
102 unsigned char *pixels = s->frame.data[0];
103 int stride = s->frame.linesize[0];
104
105 stream_ptr = 0;
106 skip_blocks = 0;
107 blocks_wide = s->avctx->width / 4;
108 blocks_high = s->avctx->height / 4;
109 total_blocks = blocks_wide * blocks_high;
110 block_inc = 4;
111 row_dec = stride + 4;
112
113 for (block_y = blocks_high; block_y > 0; block_y--) {
114 block_ptr = ((block_y * 4) - 1) * stride;
115 for (block_x = blocks_wide; block_x > 0; block_x--) {
116 /* check if this block should be skipped */
117 if (skip_blocks) {
118 block_ptr += block_inc;
119 skip_blocks--;
120 total_blocks--;
121 continue;
122 }
123
124 pixel_ptr = block_ptr;
125
126 /* get the next two bytes in the encoded data stream */
127 CHECK_STREAM_PTR(2);
128 byte_a = s->buf[stream_ptr++];
129 byte_b = s->buf[stream_ptr++];
130
131 /* check if the decode is finished */
132 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
133 return;
134 else if ((byte_b & 0xFC) == 0x84) {
135 /* skip code, but don't count the current block */
136 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
137 } else if (byte_b < 0x80) {
138 /* 2-color encoding */
139 flags = (byte_b << 8) | byte_a;
140
141 CHECK_STREAM_PTR(2);
142 colors[0] = s->buf[stream_ptr++];
143 colors[1] = s->buf[stream_ptr++];
144
145 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
146 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
147 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
148 pixel_ptr -= row_dec;
149 }
150 } else if (byte_b >= 0x90) {
151 /* 8-color encoding */
152 flags = (byte_b << 8) | byte_a;
153
154 CHECK_STREAM_PTR(8);
155 memcpy(colors, &s->buf[stream_ptr], 8);
156 stream_ptr += 8;
157
158 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
159 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
160 pixels[pixel_ptr++] =
161 colors[((pixel_y & 0x2) << 1) +
162 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
163 pixel_ptr -= row_dec;
164 }
165 } else {
166 /* 1-color encoding */
167 colors[0] = byte_a;
168
169 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
170 for (pixel_x = 0; pixel_x < 4; pixel_x++)
171 pixels[pixel_ptr++] = colors[0];
172 pixel_ptr -= row_dec;
173 }
174 }
175
176 block_ptr += block_inc;
177 total_blocks--;
178 }
179 }
180
181 /* make the palette available on the way out */
182 if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
183 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
184 if (s->avctx->palctrl->palette_changed) {
185 s->frame.palette_has_changed = 1;
186 s->avctx->palctrl->palette_changed = 0;
187 }
188 }
189 }
190
191 static void msvideo1_decode_16bit(Msvideo1Context *s)
192 {
193 int block_ptr, pixel_ptr;
194 int total_blocks;
195 int pixel_x, pixel_y; /* pixel width and height iterators */
196 int block_x, block_y; /* block width and height iterators */
197 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
198 int block_inc;
199 int row_dec;
200
201 /* decoding parameters */
202 int stream_ptr;
203 unsigned char byte_a, byte_b;
204 unsigned short flags;
205 int skip_blocks;
206 unsigned short colors[8];
207 unsigned short *pixels = (unsigned short *)s->frame.data[0];
208 int stride = s->frame.linesize[0] / 2;
209
210 stream_ptr = 0;
211 skip_blocks = 0;
212 blocks_wide = s->avctx->width / 4;
213 blocks_high = s->avctx->height / 4;
214 total_blocks = blocks_wide * blocks_high;
215 block_inc = 4;
216 row_dec = stride + 4;
217
218 for (block_y = blocks_high; block_y > 0; block_y--) {
219 block_ptr = ((block_y * 4) - 1) * stride;
220 for (block_x = blocks_wide; block_x > 0; block_x--) {
221 /* check if this block should be skipped */
222 if (skip_blocks) {
223 block_ptr += block_inc;
224 skip_blocks--;
225 total_blocks--;
226 continue;
227 }
228
229 pixel_ptr = block_ptr;
230
231 /* get the next two bytes in the encoded data stream */
232 CHECK_STREAM_PTR(2);
233 byte_a = s->buf[stream_ptr++];
234 byte_b = s->buf[stream_ptr++];
235
236 /* check if the decode is finished */
237 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
238 return;
239 } else if ((byte_b & 0xFC) == 0x84) {
240 /* skip code, but don't count the current block */
241 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
242 } else if (byte_b < 0x80) {
243 /* 2- or 8-color encoding modes */
244 flags = (byte_b << 8) | byte_a;
245
246 CHECK_STREAM_PTR(4);
247 colors[0] = LE_16(&s->buf[stream_ptr]);
248 stream_ptr += 2;
249 colors[1] = LE_16(&s->buf[stream_ptr]);
250 stream_ptr += 2;
251
252 if (colors[0] & 0x8000) {
253 /* 8-color encoding */
254 CHECK_STREAM_PTR(12);
255 colors[2] = LE_16(&s->buf[stream_ptr]);
256 stream_ptr += 2;
257 colors[3] = LE_16(&s->buf[stream_ptr]);
258 stream_ptr += 2;
259 colors[4] = LE_16(&s->buf[stream_ptr]);
260 stream_ptr += 2;
261 colors[5] = LE_16(&s->buf[stream_ptr]);
262 stream_ptr += 2;
263 colors[6] = LE_16(&s->buf[stream_ptr]);
264 stream_ptr += 2;
265 colors[7] = LE_16(&s->buf[stream_ptr]);
266 stream_ptr += 2;
267
268 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
269 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
270 pixels[pixel_ptr++] =
271 colors[((pixel_y & 0x2) << 1) +
272 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
273 pixel_ptr -= row_dec;
274 }
275 } else {
276 /* 2-color encoding */
277 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
278 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
279 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
280 pixel_ptr -= row_dec;
281 }
282 }
283 } else {
284 /* otherwise, it's a 1-color block */
285 colors[0] = (byte_b << 8) | byte_a;
286
287 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
288 for (pixel_x = 0; pixel_x < 4; pixel_x++)
289 pixels[pixel_ptr++] = colors[0];
290 pixel_ptr -= row_dec;
291 }
292 }
293
294 block_ptr += block_inc;
295 total_blocks--;
296 }
297 }
298 }
299
300 static int msvideo1_decode_frame(AVCodecContext *avctx,
301 void *data, int *data_size,
302 uint8_t *buf, int buf_size)
303 {
304 Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
305
306 /* no supplementary picture */
307 if (buf_size == 0)
308 return 0;
309
310 s->buf = buf;
311 s->size = buf_size;
312
313 s->frame.reference = 1;
314 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
315 if (avctx->reget_buffer(avctx, &s->frame)) {
316 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
317 return -1;
318 }
319
320 if (s->mode_8bit)
321 msvideo1_decode_8bit(s);
322 else
323 msvideo1_decode_16bit(s);
324
325 *data_size = sizeof(AVFrame);
326 *(AVFrame*)data = s->frame;
327
328 /* report that the buffer was completely consumed */
329 return buf_size;
330 }
331
332 static int msvideo1_decode_end(AVCodecContext *avctx)
333 {
334 Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
335
336 if (s->frame.data[0])
337 avctx->release_buffer(avctx, &s->frame);
338
339 return 0;
340 }
341
342 AVCodec msvideo1_decoder = {
343 "msvideo1",
344 CODEC_TYPE_VIDEO,
345 CODEC_ID_MSVIDEO1,
346 sizeof(Msvideo1Context),
347 msvideo1_decode_init,
348 NULL,
349 msvideo1_decode_end,
350 msvideo1_decode_frame,
351 CODEC_CAP_DR1,
352 };