Split the h261.c file into separate files for the encoder, decoder and common stuff.
[libav.git] / libavcodec / h261enc.c
1 /*
2 * H261 encoder
3 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2004 Maarten Daniels
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file h261enc.c
25 * H.261 encoder.
26 */
27
28 #include "dsputil.h"
29 #include "avcodec.h"
30 #include "mpegvideo.h"
31 #include "h261data.h"
32 #include "h261.h"
33
34 extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3];
35
36 static void h261_encode_block(H261Context * h, DCTELEM * block,
37 int n);
38
39 int ff_h261_get_picture_format(int width, int height){
40 // QCIF
41 if (width == 176 && height == 144)
42 return 0;
43 // CIF
44 else if (width == 352 && height == 288)
45 return 1;
46 // ERROR
47 else
48 return -1;
49 }
50
51 void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){
52 H261Context * h = (H261Context *) s;
53 int format, temp_ref;
54
55 align_put_bits(&s->pb);
56
57 /* Update the pointer to last GOB */
58 s->ptr_lastgob = pbBufPtr(&s->pb);
59
60 put_bits(&s->pb, 20, 0x10); /* PSC */
61
62 temp_ref= s->picture_number * (int64_t)30000 * s->avctx->time_base.num /
63 (1001 * (int64_t)s->avctx->time_base.den); //FIXME maybe this should use a timestamp
64 put_bits(&s->pb, 5, temp_ref & 0x1f); /* TemporalReference */
65
66 put_bits(&s->pb, 1, 0); /* split screen off */
67 put_bits(&s->pb, 1, 0); /* camera off */
68 put_bits(&s->pb, 1, 0); /* freeze picture release off */
69
70 format = ff_h261_get_picture_format(s->width, s->height);
71
72 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */
73
74 put_bits(&s->pb, 1, 0); /* still image mode */
75 put_bits(&s->pb, 1, 0); /* reserved */
76
77 put_bits(&s->pb, 1, 0); /* no PEI */
78 if(format == 0)
79 h->gob_number = -1;
80 else
81 h->gob_number = 0;
82 h->current_mba = 0;
83 }
84
85 /**
86 * Encodes a group of blocks header.
87 */
88 static void h261_encode_gob_header(MpegEncContext * s, int mb_line){
89 H261Context * h = (H261Context *)s;
90 if(ff_h261_get_picture_format(s->width, s->height) == 0){
91 h->gob_number+=2; // QCIF
92 }
93 else{
94 h->gob_number++; // CIF
95 }
96 put_bits(&s->pb, 16, 1); /* GBSC */
97 put_bits(&s->pb, 4, h->gob_number); /* GN */
98 put_bits(&s->pb, 5, s->qscale); /* GQUANT */
99 put_bits(&s->pb, 1, 0); /* no GEI */
100 h->current_mba = 0;
101 h->previous_mba = 0;
102 h->current_mv_x=0;
103 h->current_mv_y=0;
104 }
105
106 void ff_h261_reorder_mb_index(MpegEncContext* s){
107 int index= s->mb_x + s->mb_y*s->mb_width;
108
109 if(index % 33 == 0)
110 h261_encode_gob_header(s,0);
111
112 /* for CIF the GOB's are fragmented in the middle of a scanline
113 that's why we need to adjust the x and y index of the macroblocks */
114 if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF
115 s->mb_x = index % 11 ; index /= 11;
116 s->mb_y = index % 3 ; index /= 3;
117 s->mb_x+= 11*(index % 2); index /= 2;
118 s->mb_y+= 3*index;
119
120 ff_init_block_index(s);
121 ff_update_block_index(s);
122 }
123 }
124
125 static void h261_encode_motion(H261Context * h, int val){
126 MpegEncContext * const s = &h->s;
127 int sign, code;
128 if(val==0){
129 code = 0;
130 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]);
131 }
132 else{
133 if(val > 15)
134 val -=32;
135 if(val < -16)
136 val+=32;
137 sign = val < 0;
138 code = sign ? -val : val;
139 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]);
140 put_bits(&s->pb,1,sign);
141 }
142 }
143
144 static inline int get_cbp(MpegEncContext * s,
145 DCTELEM block[6][64])
146 {
147 int i, cbp;
148 cbp= 0;
149 for (i = 0; i < 6; i++) {
150 if (s->block_last_index[i] >= 0)
151 cbp |= 1 << (5 - i);
152 }
153 return cbp;
154 }
155 void ff_h261_encode_mb(MpegEncContext * s,
156 DCTELEM block[6][64],
157 int motion_x, int motion_y)
158 {
159 H261Context * h = (H261Context *)s;
160 int mvd, mv_diff_x, mv_diff_y, i, cbp;
161 cbp = 63; // avoid warning
162 mvd = 0;
163
164 h->current_mba++;
165 h->mtype = 0;
166
167 if (!s->mb_intra){
168 /* compute cbp */
169 cbp= get_cbp(s, block);
170
171 /* mvd indicates if this block is motion compensated */
172 mvd = motion_x | motion_y;
173
174 if((cbp | mvd | s->dquant ) == 0) {
175 /* skip macroblock */
176 s->skip_count++;
177 h->current_mv_x=0;
178 h->current_mv_y=0;
179 return;
180 }
181 }
182
183 /* MB is not skipped, encode MBA */
184 put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]);
185
186 /* calculate MTYPE */
187 if(!s->mb_intra){
188 h->mtype++;
189
190 if(mvd || s->loop_filter)
191 h->mtype+=3;
192 if(s->loop_filter)
193 h->mtype+=3;
194 if(cbp || s->dquant)
195 h->mtype++;
196 assert(h->mtype > 1);
197 }
198
199 if(s->dquant)
200 h->mtype++;
201
202 put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]);
203
204 h->mtype = h261_mtype_map[h->mtype];
205
206 if(IS_QUANT(h->mtype)){
207 ff_set_qscale(s,s->qscale+s->dquant);
208 put_bits(&s->pb, 5, s->qscale);
209 }
210
211 if(IS_16X16(h->mtype)){
212 mv_diff_x = (motion_x >> 1) - h->current_mv_x;
213 mv_diff_y = (motion_y >> 1) - h->current_mv_y;
214 h->current_mv_x = (motion_x >> 1);
215 h->current_mv_y = (motion_y >> 1);
216 h261_encode_motion(h,mv_diff_x);
217 h261_encode_motion(h,mv_diff_y);
218 }
219
220 h->previous_mba = h->current_mba;
221
222 if(HAS_CBP(h->mtype)){
223 assert(cbp>0);
224 put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]);
225 }
226 for(i=0; i<6; i++) {
227 /* encode each block */
228 h261_encode_block(h, block[i], i);
229 }
230
231 if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){
232 h->current_mv_x=0;
233 h->current_mv_y=0;
234 }
235 }
236
237 void ff_h261_encode_init(MpegEncContext *s){
238 static int done = 0;
239
240 if (!done) {
241 done = 1;
242 init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store);
243 }
244
245 s->min_qcoeff= -127;
246 s->max_qcoeff= 127;
247 s->y_dc_scale_table=
248 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
249 }
250
251
252 /**
253 * encodes a 8x8 block.
254 * @param block the 8x8 block
255 * @param n block index (0-3 are luma, 4-5 are chroma)
256 */
257 static void h261_encode_block(H261Context * h, DCTELEM * block, int n){
258 MpegEncContext * const s = &h->s;
259 int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code;
260 RLTable *rl;
261
262 rl = &h261_rl_tcoeff;
263 if (s->mb_intra) {
264 /* DC coef */
265 level = block[0];
266 /* 255 cannot be represented, so we clamp */
267 if (level > 254) {
268 level = 254;
269 block[0] = 254;
270 }
271 /* 0 cannot be represented also */
272 else if (level < 1) {
273 level = 1;
274 block[0] = 1;
275 }
276 if (level == 128)
277 put_bits(&s->pb, 8, 0xff);
278 else
279 put_bits(&s->pb, 8, level);
280 i = 1;
281 } else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){
282 //special case
283 put_bits(&s->pb,2,block[0]>0 ? 2 : 3 );
284 i = 1;
285 } else {
286 i = 0;
287 }
288
289 /* AC coefs */
290 last_index = s->block_last_index[n];
291 last_non_zero = i - 1;
292 for (; i <= last_index; i++) {
293 j = s->intra_scantable.permutated[i];
294 level = block[j];
295 if (level) {
296 run = i - last_non_zero - 1;
297 last = (i == last_index);
298 sign = 0;
299 slevel = level;
300 if (level < 0) {
301 sign = 1;
302 level = -level;
303 }
304 code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, run, level);
305 if(run==0 && level < 16)
306 code+=1;
307 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
308 if (code == rl->n) {
309 put_bits(&s->pb, 6, run);
310 assert(slevel != 0);
311 assert(level <= 127);
312 put_bits(&s->pb, 8, slevel & 0xff);
313 } else {
314 put_bits(&s->pb, 1, sign);
315 }
316 last_non_zero = i;
317 }
318 }
319 if(last_index > -1){
320 put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]);// END OF BLOCK
321 }
322 }
323
324 AVCodec h261_encoder = {
325 "h261",
326 CODEC_TYPE_VIDEO,
327 CODEC_ID_H261,
328 sizeof(H261Context),
329 MPV_encode_init,
330 MPV_encode_picture,
331 MPV_encode_end,
332 .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1},
333 };
334