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 libavcodec/msvideo1.c
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 * This decoder outputs either PAL8 or RGB555 data, depending on the
29 * whether a RGB palette was passed through palctrl;
30 * if it's present, then the data is PAL8; RGB555 otherwise.
31 */
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36#include <unistd.h>
37
38#include "libavutil/intreadwrite.h"
39#include "avcodec.h"
40
41#define PALETTE_COUNT 256
42#define CHECK_STREAM_PTR(n) \
43  if ((stream_ptr + n) > s->size ) { \
44    av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
45      stream_ptr + n, s->size); \
46    return; \
47  }
48
49typedef struct Msvideo1Context {
50
51    AVCodecContext *avctx;
52    AVFrame frame;
53
54    const unsigned char *buf;
55    int size;
56
57    int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
58
59} Msvideo1Context;
60
61static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
62{
63    Msvideo1Context *s = avctx->priv_data;
64
65    s->avctx = avctx;
66
67    /* figure out the colorspace based on the presence of a palette */
68    if (s->avctx->palctrl) {
69        s->mode_8bit = 1;
70        avctx->pix_fmt = PIX_FMT_PAL8;
71    } else {
72        s->mode_8bit = 0;
73        avctx->pix_fmt = PIX_FMT_RGB555;
74    }
75
76    s->frame.data[0] = NULL;
77
78    return 0;
79}
80
81static void msvideo1_decode_8bit(Msvideo1Context *s)
82{
83    int block_ptr, pixel_ptr;
84    int total_blocks;
85    int pixel_x, pixel_y;  /* pixel width and height iterators */
86    int block_x, block_y;  /* block width and height iterators */
87    int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
88    int block_inc;
89    int row_dec;
90
91    /* decoding parameters */
92    int stream_ptr;
93    unsigned char byte_a, byte_b;
94    unsigned short flags;
95    int skip_blocks;
96    unsigned char colors[8];
97    unsigned char *pixels = s->frame.data[0];
98    int stride = s->frame.linesize[0];
99
100    stream_ptr = 0;
101    skip_blocks = 0;
102    blocks_wide = s->avctx->width / 4;
103    blocks_high = s->avctx->height / 4;
104    total_blocks = blocks_wide * blocks_high;
105    block_inc = 4;
106    row_dec = stride + 4;
107
108    for (block_y = blocks_high; block_y > 0; block_y--) {
109        block_ptr = ((block_y * 4) - 1) * stride;
110        for (block_x = blocks_wide; block_x > 0; block_x--) {
111            /* check if this block should be skipped */
112            if (skip_blocks) {
113                block_ptr += block_inc;
114                skip_blocks--;
115                total_blocks--;
116                continue;
117            }
118
119            pixel_ptr = block_ptr;
120
121            /* get the next two bytes in the encoded data stream */
122            CHECK_STREAM_PTR(2);
123            byte_a = s->buf[stream_ptr++];
124            byte_b = s->buf[stream_ptr++];
125
126            /* check if the decode is finished */
127            if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
128                return;
129            else if ((byte_b & 0xFC) == 0x84) {
130                /* skip code, but don't count the current block */
131                skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
132            } else if (byte_b < 0x80) {
133                /* 2-color encoding */
134                flags = (byte_b << 8) | byte_a;
135
136                CHECK_STREAM_PTR(2);
137                colors[0] = s->buf[stream_ptr++];
138                colors[1] = s->buf[stream_ptr++];
139
140                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
141                    for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
142                        pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
143                    pixel_ptr -= row_dec;
144                }
145            } else if (byte_b >= 0x90) {
146                /* 8-color encoding */
147                flags = (byte_b << 8) | byte_a;
148
149                CHECK_STREAM_PTR(8);
150                memcpy(colors, &s->buf[stream_ptr], 8);
151                stream_ptr += 8;
152
153                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
154                    for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
155                        pixels[pixel_ptr++] =
156                            colors[((pixel_y & 0x2) << 1) +
157                                (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
158                    pixel_ptr -= row_dec;
159                }
160            } else {
161                /* 1-color encoding */
162                colors[0] = byte_a;
163
164                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
165                    for (pixel_x = 0; pixel_x < 4; pixel_x++)
166                        pixels[pixel_ptr++] = colors[0];
167                    pixel_ptr -= row_dec;
168                }
169            }
170
171            block_ptr += block_inc;
172            total_blocks--;
173        }
174    }
175
176    /* make the palette available on the way out */
177    if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
178        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
179        if (s->avctx->palctrl->palette_changed) {
180            s->frame.palette_has_changed = 1;
181            s->avctx->palctrl->palette_changed = 0;
182        }
183    }
184}
185
186static 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
295static int msvideo1_decode_frame(AVCodecContext *avctx,
296                                void *data, int *data_size,
297                                const uint8_t *buf, int buf_size)
298{
299    Msvideo1Context *s = avctx->priv_data;
300
301    s->buf = buf;
302    s->size = buf_size;
303
304    s->frame.reference = 1;
305    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
306    if (avctx->reget_buffer(avctx, &s->frame)) {
307        av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
308        return -1;
309    }
310
311    if (s->mode_8bit)
312        msvideo1_decode_8bit(s);
313    else
314        msvideo1_decode_16bit(s);
315
316    *data_size = sizeof(AVFrame);
317    *(AVFrame*)data = s->frame;
318
319    /* report that the buffer was completely consumed */
320    return buf_size;
321}
322
323static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
324{
325    Msvideo1Context *s = avctx->priv_data;
326
327    if (s->frame.data[0])
328        avctx->release_buffer(avctx, &s->frame);
329
330    return 0;
331}
332
333AVCodec msvideo1_decoder = {
334    "msvideo1",
335    CODEC_TYPE_VIDEO,
336    CODEC_ID_MSVIDEO1,
337    sizeof(Msvideo1Context),
338    msvideo1_decode_init,
339    NULL,
340    msvideo1_decode_end,
341    msvideo1_decode_frame,
342    CODEC_CAP_DR1,
343    .long_name= NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
344};
345