1/*
2 * KMVC decoder
3 * Copyright (c) 2006 Konstantin Shishkov
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 * Karl Morton's Video Codec decoder
25 */
26
27#include <stdio.h>
28#include <stdlib.h>
29
30#include "avcodec.h"
31#include "bytestream.h"
32
33#define KMVC_KEYFRAME 0x80
34#define KMVC_PALETTE  0x40
35#define KMVC_METHOD   0x0F
36
37/*
38 * Decoder context
39 */
40typedef struct KmvcContext {
41    AVCodecContext *avctx;
42    AVFrame pic;
43
44    int setpal;
45    int palsize;
46    uint32_t pal[256];
47    uint8_t *cur, *prev;
48    uint8_t *frm0, *frm1;
49} KmvcContext;
50
51typedef struct BitBuf {
52    int bits;
53    int bitbuf;
54} BitBuf;
55
56#define BLK(data, x, y)  data[(x) + (y) * 320]
57
58#define kmvc_init_getbits(bb, src)  bb.bits = 7; bb.bitbuf = *src++;
59
60#define kmvc_getbit(bb, src, res) {\
61    res = 0; \
62    if (bb.bitbuf & (1 << bb.bits)) res = 1; \
63    bb.bits--; \
64    if(bb.bits == -1) { \
65        bb.bitbuf = *src++; \
66        bb.bits = 7; \
67    } \
68}
69
70static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
71{
72    BitBuf bb;
73    int res, val;
74    int i, j;
75    int bx, by;
76    int l0x, l1x, l0y, l1y;
77    int mx, my;
78
79    kmvc_init_getbits(bb, src);
80
81    for (by = 0; by < h; by += 8)
82        for (bx = 0; bx < w; bx += 8) {
83            kmvc_getbit(bb, src, res);
84            if (!res) {         // fill whole 8x8 block
85                val = *src++;
86                for (i = 0; i < 64; i++)
87                    BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
88            } else {            // handle four 4x4 subblocks
89                for (i = 0; i < 4; i++) {
90                    l0x = bx + (i & 1) * 4;
91                    l0y = by + (i & 2) * 2;
92                    kmvc_getbit(bb, src, res);
93                    if (!res) {
94                        kmvc_getbit(bb, src, res);
95                        if (!res) {     // fill whole 4x4 block
96                            val = *src++;
97                            for (j = 0; j < 16; j++)
98                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
99                        } else {        // copy block from already decoded place
100                            val = *src++;
101                            mx = val & 0xF;
102                            my = val >> 4;
103                            for (j = 0; j < 16; j++)
104                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
105                                    BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
106                        }
107                    } else {    // descend to 2x2 sub-sub-blocks
108                        for (j = 0; j < 4; j++) {
109                            l1x = l0x + (j & 1) * 2;
110                            l1y = l0y + (j & 2);
111                            kmvc_getbit(bb, src, res);
112                            if (!res) {
113                                kmvc_getbit(bb, src, res);
114                                if (!res) {     // fill whole 2x2 block
115                                    val = *src++;
116                                    BLK(ctx->cur, l1x, l1y) = val;
117                                    BLK(ctx->cur, l1x + 1, l1y) = val;
118                                    BLK(ctx->cur, l1x, l1y + 1) = val;
119                                    BLK(ctx->cur, l1x + 1, l1y + 1) = val;
120                                } else {        // copy block from already decoded place
121                                    val = *src++;
122                                    mx = val & 0xF;
123                                    my = val >> 4;
124                                    BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
125                                    BLK(ctx->cur, l1x + 1, l1y) =
126                                        BLK(ctx->cur, l1x + 1 - mx, l1y - my);
127                                    BLK(ctx->cur, l1x, l1y + 1) =
128                                        BLK(ctx->cur, l1x - mx, l1y + 1 - my);
129                                    BLK(ctx->cur, l1x + 1, l1y + 1) =
130                                        BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
131                                }
132                            } else {    // read values for block
133                                BLK(ctx->cur, l1x, l1y) = *src++;
134                                BLK(ctx->cur, l1x + 1, l1y) = *src++;
135                                BLK(ctx->cur, l1x, l1y + 1) = *src++;
136                                BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
137                            }
138                        }
139                    }
140                }
141            }
142        }
143}
144
145static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
146{
147    BitBuf bb;
148    int res, val;
149    int i, j;
150    int bx, by;
151    int l0x, l1x, l0y, l1y;
152    int mx, my;
153
154    kmvc_init_getbits(bb, src);
155
156    for (by = 0; by < h; by += 8)
157        for (bx = 0; bx < w; bx += 8) {
158            kmvc_getbit(bb, src, res);
159            if (!res) {
160                kmvc_getbit(bb, src, res);
161                if (!res) {     // fill whole 8x8 block
162                    val = *src++;
163                    for (i = 0; i < 64; i++)
164                        BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
165                } else {        // copy block from previous frame
166                    for (i = 0; i < 64; i++)
167                        BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
168                            BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
169                }
170            } else {            // handle four 4x4 subblocks
171                for (i = 0; i < 4; i++) {
172                    l0x = bx + (i & 1) * 4;
173                    l0y = by + (i & 2) * 2;
174                    kmvc_getbit(bb, src, res);
175                    if (!res) {
176                        kmvc_getbit(bb, src, res);
177                        if (!res) {     // fill whole 4x4 block
178                            val = *src++;
179                            for (j = 0; j < 16; j++)
180                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
181                        } else {        // copy block
182                            val = *src++;
183                            mx = (val & 0xF) - 8;
184                            my = (val >> 4) - 8;
185                            for (j = 0; j < 16; j++)
186                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
187                                    BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
188                        }
189                    } else {    // descend to 2x2 sub-sub-blocks
190                        for (j = 0; j < 4; j++) {
191                            l1x = l0x + (j & 1) * 2;
192                            l1y = l0y + (j & 2);
193                            kmvc_getbit(bb, src, res);
194                            if (!res) {
195                                kmvc_getbit(bb, src, res);
196                                if (!res) {     // fill whole 2x2 block
197                                    val = *src++;
198                                    BLK(ctx->cur, l1x, l1y) = val;
199                                    BLK(ctx->cur, l1x + 1, l1y) = val;
200                                    BLK(ctx->cur, l1x, l1y + 1) = val;
201                                    BLK(ctx->cur, l1x + 1, l1y + 1) = val;
202                                } else {        // copy block
203                                    val = *src++;
204                                    mx = (val & 0xF) - 8;
205                                    my = (val >> 4) - 8;
206                                    BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
207                                    BLK(ctx->cur, l1x + 1, l1y) =
208                                        BLK(ctx->prev, l1x + 1 + mx, l1y + my);
209                                    BLK(ctx->cur, l1x, l1y + 1) =
210                                        BLK(ctx->prev, l1x + mx, l1y + 1 + my);
211                                    BLK(ctx->cur, l1x + 1, l1y + 1) =
212                                        BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
213                                }
214                            } else {    // read values for block
215                                BLK(ctx->cur, l1x, l1y) = *src++;
216                                BLK(ctx->cur, l1x + 1, l1y) = *src++;
217                                BLK(ctx->cur, l1x, l1y + 1) = *src++;
218                                BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
219                            }
220                        }
221                    }
222                }
223            }
224        }
225}
226
227static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt)
228{
229    const uint8_t *buf = avpkt->data;
230    int buf_size = avpkt->size;
231    KmvcContext *const ctx = avctx->priv_data;
232    uint8_t *out, *src;
233    int i;
234    int header;
235    int blocksize;
236
237    if (ctx->pic.data[0])
238        avctx->release_buffer(avctx, &ctx->pic);
239
240    ctx->pic.reference = 1;
241    ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
242    if (avctx->get_buffer(avctx, &ctx->pic) < 0) {
243        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
244        return -1;
245    }
246
247    header = *buf++;
248
249    /* blocksize 127 is really palette change event */
250    if (buf[0] == 127) {
251        buf += 3;
252        for (i = 0; i < 127; i++) {
253            ctx->pal[i + (header & 0x81)] = AV_RB24(buf);
254            buf += 4;
255        }
256        buf -= 127 * 4 + 3;
257    }
258
259    if (header & KMVC_KEYFRAME) {
260        ctx->pic.key_frame = 1;
261        ctx->pic.pict_type = FF_I_TYPE;
262    } else {
263        ctx->pic.key_frame = 0;
264        ctx->pic.pict_type = FF_P_TYPE;
265    }
266
267    /* if palette has been changed, copy it from palctrl */
268    if (ctx->avctx->palctrl && ctx->avctx->palctrl->palette_changed) {
269        memcpy(ctx->pal, ctx->avctx->palctrl->palette, AVPALETTE_SIZE);
270        ctx->setpal = 1;
271        ctx->avctx->palctrl->palette_changed = 0;
272    }
273
274    if (header & KMVC_PALETTE) {
275        ctx->pic.palette_has_changed = 1;
276        // palette starts from index 1 and has 127 entries
277        for (i = 1; i <= ctx->palsize; i++) {
278            ctx->pal[i] = bytestream_get_be24(&buf);
279        }
280    }
281
282    if (ctx->setpal) {
283        ctx->setpal = 0;
284        ctx->pic.palette_has_changed = 1;
285    }
286
287    /* make the palette available on the way out */
288    memcpy(ctx->pic.data[1], ctx->pal, 1024);
289
290    blocksize = *buf++;
291
292    if (blocksize != 8 && blocksize != 127) {
293        av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
294        return -1;
295    }
296    memset(ctx->cur, 0, 320 * 200);
297    switch (header & KMVC_METHOD) {
298    case 0:
299    case 1: // used in palette changed event
300        memcpy(ctx->cur, ctx->prev, 320 * 200);
301        break;
302    case 3:
303        kmvc_decode_intra_8x8(ctx, buf, avctx->width, avctx->height);
304        break;
305    case 4:
306        kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height);
307        break;
308    default:
309        av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
310        return -1;
311    }
312
313    out = ctx->pic.data[0];
314    src = ctx->cur;
315    for (i = 0; i < avctx->height; i++) {
316        memcpy(out, src, avctx->width);
317        src += 320;
318        out += ctx->pic.linesize[0];
319    }
320
321    /* flip buffers */
322    if (ctx->cur == ctx->frm0) {
323        ctx->cur = ctx->frm1;
324        ctx->prev = ctx->frm0;
325    } else {
326        ctx->cur = ctx->frm0;
327        ctx->prev = ctx->frm1;
328    }
329
330    *data_size = sizeof(AVFrame);
331    *(AVFrame *) data = ctx->pic;
332
333    /* always report that the buffer was completely consumed */
334    return buf_size;
335}
336
337
338
339/*
340 * Init kmvc decoder
341 */
342static av_cold int decode_init(AVCodecContext * avctx)
343{
344    KmvcContext *const c = avctx->priv_data;
345    int i;
346
347    c->avctx = avctx;
348
349    if (avctx->width > 320 || avctx->height > 200) {
350        av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
351        return -1;
352    }
353
354    c->frm0 = av_mallocz(320 * 200);
355    c->frm1 = av_mallocz(320 * 200);
356    c->cur = c->frm0;
357    c->prev = c->frm1;
358
359    for (i = 0; i < 256; i++) {
360        c->pal[i] = i * 0x10101;
361    }
362
363    if (avctx->extradata_size < 12) {
364        av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n");
365        c->palsize = 127;
366    } else {
367        c->palsize = AV_RL16(avctx->extradata + 10);
368    }
369
370    if (avctx->extradata_size == 1036) {        // palette in extradata
371        uint8_t *src = avctx->extradata + 12;
372        for (i = 0; i < 256; i++) {
373            c->pal[i] = AV_RL32(src);
374            src += 4;
375        }
376        c->setpal = 1;
377        if (c->avctx->palctrl) {
378            c->avctx->palctrl->palette_changed = 0;
379        }
380    }
381
382    avctx->pix_fmt = PIX_FMT_PAL8;
383
384    return 0;
385}
386
387
388
389/*
390 * Uninit kmvc decoder
391 */
392static av_cold int decode_end(AVCodecContext * avctx)
393{
394    KmvcContext *const c = avctx->priv_data;
395
396    av_freep(&c->frm0);
397    av_freep(&c->frm1);
398    if (c->pic.data[0])
399        avctx->release_buffer(avctx, &c->pic);
400
401    return 0;
402}
403
404AVCodec kmvc_decoder = {
405    "kmvc",
406    AVMEDIA_TYPE_VIDEO,
407    CODEC_ID_KMVC,
408    sizeof(KmvcContext),
409    decode_init,
410    NULL,
411    decode_end,
412    decode_frame,
413    CODEC_CAP_DR1,
414    .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
415};
416