1/*
2 * Microsoft Video-1 Encoder
3 * Copyright (c) 2009 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 * Microsoft Video-1 encoder
25 */
26
27#include "avcodec.h"
28#include "internal.h"
29#include "bytestream.h"
30#include "libavutil/lfg.h"
31#include "elbg.h"
32#include "libavutil/imgutils.h"
33/**
34 * Encoder context
35 */
36typedef struct Msvideo1EncContext {
37    AVCodecContext *avctx;
38    AVLFG rnd;
39    uint8_t *prev;
40
41    int block[16*3];
42    int block2[16*3];
43    int codebook[8*3];
44    int codebook2[8*3];
45    int output[16*3];
46    int output2[16*3];
47    int avg[3];
48    int bestpos;
49    int keyint;
50} Msvideo1EncContext;
51
52enum MSV1Mode{
53    MODE_SKIP = 0,
54    MODE_FILL,
55    MODE_2COL,
56    MODE_8COL,
57};
58
59#define SKIP_PREFIX 0x8400
60#define SKIPS_MAX 0x03FF
61#define MKRGB555(in, off) (((in)[off] << 10) | ((in)[(off) + 1] << 5) | ((in)[(off) + 2]))
62
63static const int remap[16] = { 0, 1, 4, 5, 2, 3, 6, 7, 8, 9, 12, 13, 10, 11, 14, 15 };
64
65static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
66                               const AVFrame *pict, int *got_packet)
67{
68    Msvideo1EncContext * const c = avctx->priv_data;
69    const AVFrame *p = pict;
70    uint16_t *src;
71    uint8_t *prevptr;
72    uint8_t *dst, *buf;
73    int keyframe = 0;
74    int no_skips = 1;
75    int i, j, k, x, y, ret;
76    int skips = 0;
77    int quality = 24;
78
79    if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*9 + FF_MIN_BUFFER_SIZE)) < 0)
80        return ret;
81    dst= buf= pkt->data;
82
83    if(!c->prev)
84        c->prev = av_malloc(avctx->width * 3 * (avctx->height + 3));
85    prevptr = c->prev + avctx->width * 3 * (FFALIGN(avctx->height, 4) - 1);
86    src = (uint16_t*)(p->data[0] + p->linesize[0]*(FFALIGN(avctx->height, 4) - 1));
87    if(c->keyint >= avctx->keyint_min)
88        keyframe = 1;
89
90
91    for(y = 0; y < avctx->height; y += 4){
92        for(x = 0; x < avctx->width; x += 4){
93            int bestmode = MODE_SKIP;
94            int bestscore = INT_MAX;
95            int flags = 0;
96            int score;
97
98            for(j = 0; j < 4; j++){
99                for(i = 0; i < 4; i++){
100                    uint16_t val = src[x + i - j*p->linesize[0]/2];
101                    for(k = 0; k < 3; k++){
102                        c->block[(i + j*4)*3 + k] =
103                        c->block2[remap[i + j*4]*3 + k] = (val >> (10-k*5)) & 0x1F;
104                    }
105                }
106            }
107            if(!keyframe){
108                bestscore = 0;
109                for(j = 0; j < 4; j++){
110                    for(i = 0; i < 4*3; i++){
111                        int t = prevptr[x*3 + i - j*3*avctx->width] - c->block[i + j*4*3];
112                        bestscore += t*t;
113                    }
114                }
115                bestscore /= quality;
116            }
117            // try to find optimal value to fill whole 4x4 block
118            score = 0;
119            avpriv_init_elbg(c->block, 3, 16, c->avg, 1, 1, c->output, &c->rnd);
120            avpriv_do_elbg  (c->block, 3, 16, c->avg, 1, 1, c->output, &c->rnd);
121            if(c->avg[0] == 1) // red component = 1 will be written as skip code
122                c->avg[0] = 0;
123            for(j = 0; j < 4; j++){
124                for(i = 0; i < 4; i++){
125                    for(k = 0; k < 3; k++){
126                        int t = c->avg[k] - c->block[(i+j*4)*3+k];
127                        score += t*t;
128                    }
129                }
130            }
131            score /= quality;
132            score += 2;
133            if(score < bestscore){
134                bestscore = score;
135                bestmode = MODE_FILL;
136            }
137            // search for optimal filling of 2-color block
138            score = 0;
139            avpriv_init_elbg(c->block, 3, 16, c->codebook, 2, 1, c->output, &c->rnd);
140            avpriv_do_elbg  (c->block, 3, 16, c->codebook, 2, 1, c->output, &c->rnd);
141            // last output value should be always 1, swap codebooks if needed
142            if(!c->output[15]){
143                for(i = 0; i < 3; i++)
144                    FFSWAP(uint8_t, c->codebook[i], c->codebook[i+3]);
145                for(i = 0; i < 16; i++)
146                    c->output[i] ^= 1;
147            }
148            for(j = 0; j < 4; j++){
149                for(i = 0; i < 4; i++){
150                    for(k = 0; k < 3; k++){
151                        int t = c->codebook[c->output[i+j*4]*3 + k] - c->block[i*3+k+j*4*3];
152                        score += t*t;
153                    }
154                }
155            }
156            score /= quality;
157            score += 6;
158            if(score < bestscore){
159                bestscore = score;
160                bestmode = MODE_2COL;
161            }
162            // search for optimal filling of 2-color 2x2 subblocks
163            score = 0;
164            for(i = 0; i < 4; i++){
165                avpriv_init_elbg(c->block2 + i*4*3, 3, 4, c->codebook2 + i*2*3, 2, 1, c->output2 + i*4, &c->rnd);
166                avpriv_do_elbg  (c->block2 + i*4*3, 3, 4, c->codebook2 + i*2*3, 2, 1, c->output2 + i*4, &c->rnd);
167            }
168            // last value should be always 1, swap codebooks if needed
169            if(!c->output2[15]){
170                for(i = 0; i < 3; i++)
171                    FFSWAP(uint8_t, c->codebook2[i+18], c->codebook2[i+21]);
172                for(i = 12; i < 16; i++)
173                    c->output2[i] ^= 1;
174            }
175            for(j = 0; j < 4; j++){
176                for(i = 0; i < 4; i++){
177                    for(k = 0; k < 3; k++){
178                        int t = c->codebook2[(c->output2[remap[i+j*4]] + (i&2) + (j&2)*2)*3+k] - c->block[i*3+k + j*4*3];
179                        score += t*t;
180                    }
181                }
182            }
183            score /= quality;
184            score += 18;
185            if(score < bestscore){
186                bestscore = score;
187                bestmode = MODE_8COL;
188            }
189
190            if(bestmode == MODE_SKIP){
191                skips++;
192                no_skips = 0;
193            }
194            if((bestmode != MODE_SKIP && skips) || skips == SKIPS_MAX){
195                bytestream_put_le16(&dst, skips | SKIP_PREFIX);
196                skips = 0;
197            }
198
199            switch(bestmode){
200            case MODE_FILL:
201                bytestream_put_le16(&dst, MKRGB555(c->avg,0) | 0x8000);
202                for(j = 0; j < 4; j++)
203                    for(i = 0; i < 4; i++)
204                        for(k = 0; k < 3; k++)
205                            prevptr[x*3 + i*3 + k - j*3*avctx->width] = c->avg[k];
206                break;
207            case MODE_2COL:
208                for(j = 0; j < 4; j++){
209                    for(i = 0; i < 4; i++){
210                        flags |= (c->output[i + j*4]^1) << (i + j*4);
211                        for(k = 0; k < 3; k++)
212                            prevptr[x*3 + i*3 + k - j*3*avctx->width] = c->codebook[c->output[i + j*4]*3 + k];
213                    }
214                }
215                bytestream_put_le16(&dst, flags);
216                bytestream_put_le16(&dst, MKRGB555(c->codebook, 0));
217                bytestream_put_le16(&dst, MKRGB555(c->codebook, 3));
218                break;
219            case MODE_8COL:
220                for(j = 0; j < 4; j++){
221                    for(i = 0; i < 4; i++){
222                        flags |= (c->output2[remap[i + j*4]]^1) << (i + j*4);
223                        for(k = 0; k < 3; k++)
224                            prevptr[x*3 + i*3 + k - j*3*avctx->width] = c->codebook2[(c->output2[remap[i+j*4]] + (i&2) + (j&2)*2)*3 + k];
225                    }
226                }
227                bytestream_put_le16(&dst, flags);
228                bytestream_put_le16(&dst, MKRGB555(c->codebook2, 0) | 0x8000);
229                for(i = 3; i < 24; i += 3)
230                    bytestream_put_le16(&dst, MKRGB555(c->codebook2, i));
231                break;
232            }
233        }
234        src     -= p->linesize[0] << 1;
235        prevptr -= avctx->width * 3 * 4;
236    }
237    if(skips)
238        bytestream_put_le16(&dst, skips | SKIP_PREFIX);
239    //EOF
240    bytestream_put_byte(&dst, 0);
241    bytestream_put_byte(&dst, 0);
242
243    if(no_skips)
244        keyframe = 1;
245    if(keyframe)
246        c->keyint = 0;
247    else
248        c->keyint++;
249    if (keyframe) pkt->flags |= AV_PKT_FLAG_KEY;
250    pkt->size = dst - buf;
251    *got_packet = 1;
252
253    return 0;
254}
255
256
257/**
258 * init encoder
259 */
260static av_cold int encode_init(AVCodecContext *avctx)
261{
262    Msvideo1EncContext * const c = avctx->priv_data;
263
264    c->avctx = avctx;
265    if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
266        return -1;
267    }
268    if((avctx->width&3) || (avctx->height&3)){
269        av_log(avctx, AV_LOG_ERROR, "width and height must be multiplies of 4\n");
270        return -1;
271    }
272
273    avctx->bits_per_coded_sample = 16;
274
275    c->keyint = avctx->keyint_min;
276    av_lfg_init(&c->rnd, 1);
277
278    return 0;
279}
280
281
282
283/**
284 * Uninit encoder
285 */
286static av_cold int encode_end(AVCodecContext *avctx)
287{
288    Msvideo1EncContext * const c = avctx->priv_data;
289
290    av_freep(&c->prev);
291
292    return 0;
293}
294
295AVCodec ff_msvideo1_encoder = {
296    .name           = "msvideo1",
297    .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video-1"),
298    .type           = AVMEDIA_TYPE_VIDEO,
299    .id             = AV_CODEC_ID_MSVIDEO1,
300    .priv_data_size = sizeof(Msvideo1EncContext),
301    .init           = encode_init,
302    .encode2        = encode_frame,
303    .close          = encode_end,
304    .pix_fmts = (const enum AVPixelFormat[]){AV_PIX_FMT_RGB555, AV_PIX_FMT_NONE},
305};
306