aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/msvideo1.c
blob: 0d772b9f444e4890c3b8c32b983de045acac7826 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
/*
 * Microsoft Video-1 Decoder
 * Copyright (C) 2003 the ffmpeg project
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
 * For more information about the MS Video-1 format, visit:
 *   http://www.pcisys.net/~melanson/codecs/
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"

#define PALETTE_COUNT 256
#define CHECK_STREAM_PTR(n) \
  if ((stream_ptr + n) > s->size ) { \
    av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
      stream_ptr + n, s->size); \
    return; \
  }

typedef struct Msvideo1Context {

    AVCodecContext *avctx;
    AVFrame frame;

    const unsigned char *buf;
    int size;

    int mode_8bit;  /* if it's not 8-bit, it's 16-bit */

    uint32_t pal[256];
} Msvideo1Context;

static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
{
    Msvideo1Context *s = avctx->priv_data;

    s->avctx = avctx;

    /* figure out the colorspace based on the presence of a palette */
    if (s->avctx->bits_per_coded_sample == 8) {
        s->mode_8bit = 1;
        avctx->pix_fmt = PIX_FMT_PAL8;
    } else {
        s->mode_8bit = 0;
        avctx->pix_fmt = PIX_FMT_RGB555;
    }

    s->frame.data[0] = NULL;

    return 0;
}

static void msvideo1_decode_8bit(Msvideo1Context *s)
{
    int block_ptr, pixel_ptr;
    int total_blocks;
    int pixel_x, pixel_y;  /* pixel width and height iterators */
    int block_x, block_y;  /* block width and height iterators */
    int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
    int block_inc;
    int row_dec;

    /* decoding parameters */
    int stream_ptr;
    unsigned char byte_a, byte_b;
    unsigned short flags;
    int skip_blocks;
    unsigned char colors[8];
    unsigned char *pixels = s->frame.data[0];
    int stride = s->frame.linesize[0];

    stream_ptr = 0;
    skip_blocks = 0;
    blocks_wide = s->avctx->width / 4;
    blocks_high = s->avctx->height / 4;
    total_blocks = blocks_wide * blocks_high;
    block_inc = 4;
    row_dec = stride + 4;

    for (block_y = blocks_high; block_y > 0; block_y--) {
        block_ptr = ((block_y * 4) - 1) * stride;
        for (block_x = blocks_wide; block_x > 0; block_x--) {
            /* check if this block should be skipped */
            if (skip_blocks) {
                block_ptr += block_inc;
                skip_blocks--;
                total_blocks--;
                continue;
            }

            pixel_ptr = block_ptr;

            /* get the next two bytes in the encoded data stream */
            CHECK_STREAM_PTR(2);
            byte_a = s->buf[stream_ptr++];
            byte_b = s->buf[stream_ptr++];

            /* check if the decode is finished */
            if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
                return;
            else if ((byte_b & 0xFC) == 0x84) {
                /* skip code, but don't count the current block */
                skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
            } else if (byte_b < 0x80) {
                /* 2-color encoding */
                flags = (byte_b << 8) | byte_a;

                CHECK_STREAM_PTR(2);
                colors[0] = s->buf[stream_ptr++];
                colors[1] = s->buf[stream_ptr++];

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                        pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
                    pixel_ptr -= row_dec;
                }
            } else if (byte_b >= 0x90) {
                /* 8-color encoding */
                flags = (byte_b << 8) | byte_a;

                CHECK_STREAM_PTR(8);
                memcpy(colors, &s->buf[stream_ptr], 8);
                stream_ptr += 8;

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                        pixels[pixel_ptr++] =
                            colors[((pixel_y & 0x2) << 1) +
                                (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
                    pixel_ptr -= row_dec;
                }
            } else {
                /* 1-color encoding */
                colors[0] = byte_a;

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++)
                        pixels[pixel_ptr++] = colors[0];
                    pixel_ptr -= row_dec;
                }
            }

            block_ptr += block_inc;
            total_blocks--;
        }
    }

    /* make the palette available on the way out */
    if (s->avctx->pix_fmt == PIX_FMT_PAL8)
        memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
}

static void msvideo1_decode_16bit(Msvideo1Context *s)
{
    int block_ptr, pixel_ptr;
    int total_blocks;
    int pixel_x, pixel_y;  /* pixel width and height iterators */
    int block_x, block_y;  /* block width and height iterators */
    int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
    int block_inc;
    int row_dec;

    /* decoding parameters */
    int stream_ptr;
    unsigned char byte_a, byte_b;
    unsigned short flags;
    int skip_blocks;
    unsigned short colors[8];
    unsigned short *pixels = (unsigned short *)s->frame.data[0];
    int stride = s->frame.linesize[0] / 2;

    stream_ptr = 0;
    skip_blocks = 0;
    blocks_wide = s->avctx->width / 4;
    blocks_high = s->avctx->height / 4;
    total_blocks = blocks_wide * blocks_high;
    block_inc = 4;
    row_dec = stride + 4;

    for (block_y = blocks_high; block_y > 0; block_y--) {
        block_ptr = ((block_y * 4) - 1) * stride;
        for (block_x = blocks_wide; block_x > 0; block_x--) {
            /* check if this block should be skipped */
            if (skip_blocks) {
                block_ptr += block_inc;
                skip_blocks--;
                total_blocks--;
                continue;
            }

            pixel_ptr = block_ptr;

            /* get the next two bytes in the encoded data stream */
            CHECK_STREAM_PTR(2);
            byte_a = s->buf[stream_ptr++];
            byte_b = s->buf[stream_ptr++];

            /* check if the decode is finished */
            if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
                return;
            } else if ((byte_b & 0xFC) == 0x84) {
                /* skip code, but don't count the current block */
                skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
            } else if (byte_b < 0x80) {
                /* 2- or 8-color encoding modes */
                flags = (byte_b << 8) | byte_a;

                CHECK_STREAM_PTR(4);
                colors[0] = AV_RL16(&s->buf[stream_ptr]);
                stream_ptr += 2;
                colors[1] = AV_RL16(&s->buf[stream_ptr]);
                stream_ptr += 2;

                if (colors[0] & 0x8000) {
                    /* 8-color encoding */
                    CHECK_STREAM_PTR(12);
                    colors[2] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;
                    colors[3] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;
                    colors[4] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;
                    colors[5] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;
                    colors[6] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;
                    colors[7] = AV_RL16(&s->buf[stream_ptr]);
                    stream_ptr += 2;

                    for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                        for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                            pixels[pixel_ptr++] =
                                colors[((pixel_y & 0x2) << 1) +
                                    (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
                        pixel_ptr -= row_dec;
                    }
                } else {
                    /* 2-color encoding */
                    for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                        for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                            pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
                        pixel_ptr -= row_dec;
                    }
                }
            } else {
                /* otherwise, it's a 1-color block */
                colors[0] = (byte_b << 8) | byte_a;

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++)
                        pixels[pixel_ptr++] = colors[0];
                    pixel_ptr -= row_dec;
                }
            }

            block_ptr += block_inc;
            total_blocks--;
        }
    }
}

static int msvideo1_decode_frame(AVCodecContext *avctx,
                                void *data, int *data_size,
                                AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    Msvideo1Context *s = avctx->priv_data;

    s->buf = buf;
    s->size = buf_size;

    s->frame.reference = 1;
    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    if (avctx->reget_buffer(avctx, &s->frame)) {
        av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
        return -1;
    }

    if (s->mode_8bit) {
        const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);

        if (pal) {
            memcpy(s->pal, pal, AVPALETTE_SIZE);
            s->frame.palette_has_changed = 1;
        }
    }

    if (s->mode_8bit)
        msvideo1_decode_8bit(s);
    else
        msvideo1_decode_16bit(s);

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = s->frame;

    /* report that the buffer was completely consumed */
    return buf_size;
}

static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
{
    Msvideo1Context *s = avctx->priv_data;

    if (s->frame.data[0])
        avctx->release_buffer(avctx, &s->frame);

    return 0;
}

AVCodec ff_msvideo1_decoder = {
    .name           = "msvideo1",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_MSVIDEO1,
    .priv_data_size = sizeof(Msvideo1Context),
    .init           = msvideo1_decode_init,
    .close          = msvideo1_decode_end,
    .decode         = msvideo1_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
};