1 /*
2 * Microsoft Video-1 Decoder
3 * Copyright (C) 2003 The FFmpeg project
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 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the MS Video-1 format, visit:
26 * http://www.pcisys.net/~melanson/codecs/
27 */
28
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32
33 #include "libavutil/internal.h"
34 #include "libavutil/intreadwrite.h"
35 #include "avcodec.h"
36 #include "internal.h"
37
38 #define PALETTE_COUNT 256
39 #define CHECK_STREAM_PTR(n) \
40 if ((stream_ptr + n) > s->size ) { \
41 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
42 stream_ptr + n, s->size); \
43 return; \
44 }
45
46 typedef struct Msvideo1Context {
47
48 AVCodecContext *avctx;
49 AVFrame *frame;
50
51 const unsigned char *buf;
52 int size;
53
54 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
55
56 uint32_t pal[256];
57 } Msvideo1Context;
58
msvideo1_decode_init(AVCodecContext * avctx)59 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
60 {
61 Msvideo1Context *s = avctx->priv_data;
62
63 s->avctx = avctx;
64
65 if (avctx->width < 4 || avctx->height < 4)
66 return AVERROR_INVALIDDATA;
67
68 /* figure out the colorspace based on the presence of a palette */
69 if (s->avctx->bits_per_coded_sample == 8) {
70 s->mode_8bit = 1;
71 avctx->pix_fmt = AV_PIX_FMT_PAL8;
72 if (avctx->extradata_size >= AVPALETTE_SIZE)
73 memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
74 } else {
75 s->mode_8bit = 0;
76 avctx->pix_fmt = AV_PIX_FMT_RGB555;
77 }
78
79 s->frame = av_frame_alloc();
80 if (!s->frame)
81 return AVERROR(ENOMEM);
82
83 return 0;
84 }
85
msvideo1_decode_8bit(Msvideo1Context * s)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 == AV_PIX_FMT_PAL8)
183 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
184 }
185
msvideo1_decode_16bit(Msvideo1Context * s)186 static void msvideo1_decode_16bit(Msvideo1Context *s)
187 {
188 int block_ptr, pixel_ptr;
189 int total_blocks;
190 int pixel_x, pixel_y; /* pixel width and height iterators */
191 int block_x, block_y; /* block width and height iterators */
192 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
193 int block_inc;
194 int row_dec;
195
196 /* decoding parameters */
197 int stream_ptr;
198 unsigned char byte_a, byte_b;
199 unsigned short flags;
200 int skip_blocks;
201 unsigned short colors[8];
202 unsigned short *pixels = (unsigned short *)s->frame->data[0];
203 int stride = s->frame->linesize[0] / 2;
204
205 stream_ptr = 0;
206 skip_blocks = 0;
207 blocks_wide = s->avctx->width / 4;
208 blocks_high = s->avctx->height / 4;
209 total_blocks = blocks_wide * blocks_high;
210 block_inc = 4;
211 row_dec = stride + 4;
212
213 for (block_y = blocks_high; block_y > 0; block_y--) {
214 block_ptr = ((block_y * 4) - 1) * stride;
215 for (block_x = blocks_wide; block_x > 0; block_x--) {
216 /* check if this block should be skipped */
217 if (skip_blocks) {
218 block_ptr += block_inc;
219 skip_blocks--;
220 total_blocks--;
221 continue;
222 }
223
224 pixel_ptr = block_ptr;
225
226 /* get the next two bytes in the encoded data stream */
227 CHECK_STREAM_PTR(2);
228 byte_a = s->buf[stream_ptr++];
229 byte_b = s->buf[stream_ptr++];
230
231 /* check if the decode is finished */
232 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
233 return;
234 } else if ((byte_b & 0xFC) == 0x84) {
235 /* skip code, but don't count the current block */
236 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
237 } else if (byte_b < 0x80) {
238 /* 2- or 8-color encoding modes */
239 flags = (byte_b << 8) | byte_a;
240
241 CHECK_STREAM_PTR(4);
242 colors[0] = AV_RL16(&s->buf[stream_ptr]);
243 stream_ptr += 2;
244 colors[1] = AV_RL16(&s->buf[stream_ptr]);
245 stream_ptr += 2;
246
247 if (colors[0] & 0x8000) {
248 /* 8-color encoding */
249 CHECK_STREAM_PTR(12);
250 colors[2] = AV_RL16(&s->buf[stream_ptr]);
251 stream_ptr += 2;
252 colors[3] = AV_RL16(&s->buf[stream_ptr]);
253 stream_ptr += 2;
254 colors[4] = AV_RL16(&s->buf[stream_ptr]);
255 stream_ptr += 2;
256 colors[5] = AV_RL16(&s->buf[stream_ptr]);
257 stream_ptr += 2;
258 colors[6] = AV_RL16(&s->buf[stream_ptr]);
259 stream_ptr += 2;
260 colors[7] = AV_RL16(&s->buf[stream_ptr]);
261 stream_ptr += 2;
262
263 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
264 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
265 pixels[pixel_ptr++] =
266 colors[((pixel_y & 0x2) << 1) +
267 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
268 pixel_ptr -= row_dec;
269 }
270 } else {
271 /* 2-color encoding */
272 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
273 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
274 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
275 pixel_ptr -= row_dec;
276 }
277 }
278 } else {
279 /* otherwise, it's a 1-color block */
280 colors[0] = (byte_b << 8) | byte_a;
281
282 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
283 for (pixel_x = 0; pixel_x < 4; pixel_x++)
284 pixels[pixel_ptr++] = colors[0];
285 pixel_ptr -= row_dec;
286 }
287 }
288
289 block_ptr += block_inc;
290 total_blocks--;
291 }
292 }
293 }
294
msvideo1_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)295 static int msvideo1_decode_frame(AVCodecContext *avctx,
296 void *data, int *got_frame,
297 AVPacket *avpkt)
298 {
299 const uint8_t *buf = avpkt->data;
300 int buf_size = avpkt->size;
301 Msvideo1Context *s = avctx->priv_data;
302 int ret;
303
304 s->buf = buf;
305 s->size = buf_size;
306
307 // Discard frame if its smaller than the minimum frame size
308 if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) {
309 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
310 return AVERROR_INVALIDDATA;
311 }
312
313 if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
314 return ret;
315
316 if (s->mode_8bit) {
317 buffer_size_t size;
318 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &size);
319
320 if (pal && size == AVPALETTE_SIZE) {
321 memcpy(s->pal, pal, AVPALETTE_SIZE);
322 s->frame->palette_has_changed = 1;
323 } else if (pal) {
324 av_log(avctx, AV_LOG_ERROR, "Palette size %d is wrong\n", size);
325 }
326 }
327
328 if (s->mode_8bit)
329 msvideo1_decode_8bit(s);
330 else
331 msvideo1_decode_16bit(s);
332
333 if ((ret = av_frame_ref(data, s->frame)) < 0)
334 return ret;
335
336 *got_frame = 1;
337
338 /* report that the buffer was completely consumed */
339 return buf_size;
340 }
341
msvideo1_decode_end(AVCodecContext * avctx)342 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
343 {
344 Msvideo1Context *s = avctx->priv_data;
345
346 av_frame_free(&s->frame);
347
348 return 0;
349 }
350
351 AVCodec ff_msvideo1_decoder = {
352 .name = "msvideo1",
353 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
354 .type = AVMEDIA_TYPE_VIDEO,
355 .id = AV_CODEC_ID_MSVIDEO1,
356 .priv_data_size = sizeof(Msvideo1Context),
357 .init = msvideo1_decode_init,
358 .close = msvideo1_decode_end,
359 .decode = msvideo1_decode_frame,
360 .capabilities = AV_CODEC_CAP_DR1,
361 };
362