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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 | |
25 | * H.261 encoder. | |
26 | */ | |
27 | ||
28 | #include "libavutil/attributes.h" | |
29 | #include "libavutil/avassert.h" | |
30 | #include "avcodec.h" | |
31 | #include "mpegutils.h" | |
32 | #include "mpegvideo.h" | |
33 | #include "h263.h" | |
34 | #include "h261.h" | |
35 | ||
36 | static uint8_t uni_h261_rl_len [64*64*2*2]; | |
37 | #define UNI_ENC_INDEX(last,run,level) ((last)*128*64 + (run)*128 + (level)) | |
38 | ||
39 | int ff_h261_get_picture_format(int width, int height) | |
40 | { | |
41 | // QCIF | |
42 | if (width == 176 && height == 144) | |
43 | return 0; | |
44 | // CIF | |
45 | else if (width == 352 && height == 288) | |
46 | return 1; | |
47 | // ERROR | |
48 | else | |
49 | return -1; | |
50 | } | |
51 | ||
52 | void ff_h261_encode_picture_header(MpegEncContext *s, int picture_number) | |
53 | { | |
54 | H261Context *h = (H261Context *)s; | |
55 | int format, temp_ref; | |
56 | ||
57 | avpriv_align_put_bits(&s->pb); | |
58 | ||
59 | /* Update the pointer to last GOB */ | |
60 | s->ptr_lastgob = put_bits_ptr(&s->pb); | |
61 | ||
62 | put_bits(&s->pb, 20, 0x10); /* PSC */ | |
63 | ||
64 | temp_ref = s->picture_number * (int64_t)30000 * s->avctx->time_base.num / | |
65 | (1001 * (int64_t)s->avctx->time_base.den); // FIXME maybe this should use a timestamp | |
66 | put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */ | |
67 | ||
68 | put_bits(&s->pb, 1, 0); /* split screen off */ | |
69 | put_bits(&s->pb, 1, 0); /* camera off */ | |
70 | put_bits(&s->pb, 1, 0); /* freeze picture release off */ | |
71 | ||
72 | format = ff_h261_get_picture_format(s->width, s->height); | |
73 | ||
74 | put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ | |
75 | ||
76 | put_bits(&s->pb, 1, 0); /* still image mode */ | |
77 | put_bits(&s->pb, 1, 0); /* reserved */ | |
78 | ||
79 | put_bits(&s->pb, 1, 0); /* no PEI */ | |
80 | if (format == 0) | |
81 | h->gob_number = -1; | |
82 | else | |
83 | h->gob_number = 0; | |
84 | s->mb_skip_run = 0; | |
85 | } | |
86 | ||
87 | /** | |
88 | * Encode a group of blocks header. | |
89 | */ | |
90 | static void h261_encode_gob_header(MpegEncContext *s, int mb_line) | |
91 | { | |
92 | H261Context *h = (H261Context *)s; | |
93 | if (ff_h261_get_picture_format(s->width, s->height) == 0) { | |
94 | h->gob_number += 2; // QCIF | |
95 | } else { | |
96 | h->gob_number++; // CIF | |
97 | } | |
98 | put_bits(&s->pb, 16, 1); /* GBSC */ | |
99 | put_bits(&s->pb, 4, h->gob_number); /* GN */ | |
100 | put_bits(&s->pb, 5, s->qscale); /* GQUANT */ | |
101 | put_bits(&s->pb, 1, 0); /* no GEI */ | |
102 | s->mb_skip_run = 0; | |
103 | s->last_mv[0][0][0] = 0; | |
104 | s->last_mv[0][0][1] = 0; | |
105 | } | |
106 | ||
107 | void ff_h261_reorder_mb_index(MpegEncContext *s) | |
108 | { | |
109 | int index = s->mb_x + s->mb_y * s->mb_width; | |
110 | ||
111 | if (index % 11 == 0) { | |
112 | if (index % 33 == 0) | |
113 | h261_encode_gob_header(s, 0); | |
114 | s->last_mv[0][0][0] = 0; | |
115 | s->last_mv[0][0][1] = 0; | |
116 | } | |
117 | ||
118 | /* for CIF the GOB's are fragmented in the middle of a scanline | |
119 | * that's why we need to adjust the x and y index of the macroblocks */ | |
120 | if (ff_h261_get_picture_format(s->width, s->height) == 1) { // CIF | |
121 | s->mb_x = index % 11; | |
122 | index /= 11; | |
123 | s->mb_y = index % 3; | |
124 | index /= 3; | |
125 | s->mb_x += 11 * (index % 2); | |
126 | index /= 2; | |
127 | s->mb_y += 3 * index; | |
128 | ||
129 | ff_init_block_index(s); | |
130 | ff_update_block_index(s); | |
131 | } | |
132 | } | |
133 | ||
134 | static void h261_encode_motion(H261Context *h, int val) | |
135 | { | |
136 | MpegEncContext *const s = &h->s; | |
137 | int sign, code; | |
138 | if (val == 0) { | |
139 | code = 0; | |
140 | put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]); | |
141 | } else { | |
142 | if (val > 15) | |
143 | val -= 32; | |
144 | if (val < -16) | |
145 | val += 32; | |
146 | sign = val < 0; | |
147 | code = sign ? -val : val; | |
148 | put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]); | |
149 | put_bits(&s->pb, 1, sign); | |
150 | } | |
151 | } | |
152 | ||
153 | static inline int get_cbp(MpegEncContext *s, int16_t block[6][64]) | |
154 | { | |
155 | int i, cbp; | |
156 | cbp = 0; | |
157 | for (i = 0; i < 6; i++) | |
158 | if (s->block_last_index[i] >= 0) | |
159 | cbp |= 1 << (5 - i); | |
160 | return cbp; | |
161 | } | |
162 | ||
163 | /** | |
164 | * Encode an 8x8 block. | |
165 | * @param block the 8x8 block | |
166 | * @param n block index (0-3 are luma, 4-5 are chroma) | |
167 | */ | |
168 | static void h261_encode_block(H261Context *h, int16_t *block, int n) | |
169 | { | |
170 | MpegEncContext *const s = &h->s; | |
171 | int level, run, i, j, last_index, last_non_zero, sign, slevel, code; | |
172 | RLTable *rl; | |
173 | ||
174 | rl = &ff_h261_rl_tcoeff; | |
175 | if (s->mb_intra) { | |
176 | /* DC coef */ | |
177 | level = block[0]; | |
178 | /* 255 cannot be represented, so we clamp */ | |
179 | if (level > 254) { | |
180 | level = 254; | |
181 | block[0] = 254; | |
182 | } | |
183 | /* 0 cannot be represented also */ | |
184 | else if (level < 1) { | |
185 | level = 1; | |
186 | block[0] = 1; | |
187 | } | |
188 | if (level == 128) | |
189 | put_bits(&s->pb, 8, 0xff); | |
190 | else | |
191 | put_bits(&s->pb, 8, level); | |
192 | i = 1; | |
193 | } else if ((block[0] == 1 || block[0] == -1) && | |
194 | (s->block_last_index[n] > -1)) { | |
195 | // special case | |
196 | put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3); | |
197 | i = 1; | |
198 | } else { | |
199 | i = 0; | |
200 | } | |
201 | ||
202 | /* AC coefs */ | |
203 | last_index = s->block_last_index[n]; | |
204 | last_non_zero = i - 1; | |
205 | for (; i <= last_index; i++) { | |
206 | j = s->intra_scantable.permutated[i]; | |
207 | level = block[j]; | |
208 | if (level) { | |
209 | run = i - last_non_zero - 1; | |
210 | sign = 0; | |
211 | slevel = level; | |
212 | if (level < 0) { | |
213 | sign = 1; | |
214 | level = -level; | |
215 | } | |
216 | code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, | |
217 | run, level); | |
218 | if (run == 0 && level < 16) | |
219 | code += 1; | |
220 | put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); | |
221 | if (code == rl->n) { | |
222 | put_bits(&s->pb, 6, run); | |
223 | av_assert1(slevel != 0); | |
224 | av_assert1(level <= 127); | |
225 | put_sbits(&s->pb, 8, slevel); | |
226 | } else { | |
227 | put_bits(&s->pb, 1, sign); | |
228 | } | |
229 | last_non_zero = i; | |
230 | } | |
231 | } | |
232 | if (last_index > -1) | |
233 | put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]); // EOB | |
234 | } | |
235 | ||
236 | void ff_h261_encode_mb(MpegEncContext *s, int16_t block[6][64], | |
237 | int motion_x, int motion_y) | |
238 | { | |
239 | H261Context *h = (H261Context *)s; | |
240 | int mvd, mv_diff_x, mv_diff_y, i, cbp; | |
241 | cbp = 63; // avoid warning | |
242 | mvd = 0; | |
243 | ||
244 | h->mtype = 0; | |
245 | ||
246 | if (!s->mb_intra) { | |
247 | /* compute cbp */ | |
248 | cbp = get_cbp(s, block); | |
249 | ||
250 | /* mvd indicates if this block is motion compensated */ | |
251 | mvd = motion_x | motion_y; | |
252 | ||
253 | if ((cbp | mvd | s->dquant) == 0) { | |
254 | /* skip macroblock */ | |
255 | s->skip_count++; | |
256 | s->mb_skip_run++; | |
257 | s->last_mv[0][0][0] = 0; | |
258 | s->last_mv[0][0][1] = 0; | |
259 | return; | |
260 | } | |
261 | } | |
262 | ||
263 | /* MB is not skipped, encode MBA */ | |
264 | put_bits(&s->pb, | |
265 | ff_h261_mba_bits[s->mb_skip_run], | |
266 | ff_h261_mba_code[s->mb_skip_run]); | |
267 | s->mb_skip_run = 0; | |
268 | ||
269 | /* calculate MTYPE */ | |
270 | if (!s->mb_intra) { | |
271 | h->mtype++; | |
272 | ||
273 | if (mvd || s->loop_filter) | |
274 | h->mtype += 3; | |
275 | if (s->loop_filter) | |
276 | h->mtype += 3; | |
277 | if (cbp || s->dquant) | |
278 | h->mtype++; | |
279 | av_assert1(h->mtype > 1); | |
280 | } | |
281 | ||
282 | if (s->dquant) | |
283 | h->mtype++; | |
284 | ||
285 | put_bits(&s->pb, | |
286 | ff_h261_mtype_bits[h->mtype], | |
287 | ff_h261_mtype_code[h->mtype]); | |
288 | ||
289 | h->mtype = ff_h261_mtype_map[h->mtype]; | |
290 | ||
291 | if (IS_QUANT(h->mtype)) { | |
292 | ff_set_qscale(s, s->qscale + s->dquant); | |
293 | put_bits(&s->pb, 5, s->qscale); | |
294 | } | |
295 | ||
296 | if (IS_16X16(h->mtype)) { | |
297 | mv_diff_x = (motion_x >> 1) - s->last_mv[0][0][0]; | |
298 | mv_diff_y = (motion_y >> 1) - s->last_mv[0][0][1]; | |
299 | s->last_mv[0][0][0] = (motion_x >> 1); | |
300 | s->last_mv[0][0][1] = (motion_y >> 1); | |
301 | h261_encode_motion(h, mv_diff_x); | |
302 | h261_encode_motion(h, mv_diff_y); | |
303 | } | |
304 | ||
305 | if (HAS_CBP(h->mtype)) { | |
306 | av_assert1(cbp > 0); | |
307 | put_bits(&s->pb, | |
308 | ff_h261_cbp_tab[cbp - 1][1], | |
309 | ff_h261_cbp_tab[cbp - 1][0]); | |
310 | } | |
311 | for (i = 0; i < 6; i++) | |
312 | /* encode each block */ | |
313 | h261_encode_block(h, block[i], i); | |
314 | ||
315 | if (!IS_16X16(h->mtype)) { | |
316 | s->last_mv[0][0][0] = 0; | |
317 | s->last_mv[0][0][1] = 0; | |
318 | } | |
319 | } | |
320 | ||
321 | static av_cold void init_uni_h261_rl_tab(RLTable *rl, uint32_t *bits_tab, | |
322 | uint8_t *len_tab) | |
323 | { | |
324 | int slevel, run, last; | |
325 | ||
326 | av_assert0(MAX_LEVEL >= 64); | |
327 | av_assert0(MAX_RUN >= 63); | |
328 | ||
329 | for(slevel=-64; slevel<64; slevel++){ | |
330 | if(slevel==0) continue; | |
331 | for(run=0; run<64; run++){ | |
332 | for(last=0; last<=1; last++){ | |
333 | const int index= UNI_ENC_INDEX(last, run, slevel+64); | |
334 | int level= slevel < 0 ? -slevel : slevel; | |
335 | int len, code; | |
336 | ||
337 | len_tab[index]= 100; | |
338 | ||
339 | /* ESC0 */ | |
340 | code= get_rl_index(rl, 0, run, level); | |
341 | len= rl->table_vlc[code][1] + 1; | |
342 | if(last) | |
343 | len += 2; | |
344 | ||
345 | if(code!=rl->n && len < len_tab[index]){ | |
346 | len_tab [index]= len; | |
347 | } | |
348 | /* ESC */ | |
349 | len = rl->table_vlc[rl->n][1]; | |
350 | if(last) | |
351 | len += 2; | |
352 | ||
353 | if(len < len_tab[index]){ | |
354 | len_tab [index]= len; | |
355 | } | |
356 | } | |
357 | } | |
358 | } | |
359 | } | |
360 | ||
361 | av_cold void ff_h261_encode_init(MpegEncContext *s) | |
362 | { | |
363 | ff_h261_common_init(); | |
364 | ||
365 | s->min_qcoeff = -127; | |
366 | s->max_qcoeff = 127; | |
367 | s->y_dc_scale_table = | |
368 | s->c_dc_scale_table = ff_mpeg1_dc_scale_table; | |
369 | s->ac_esc_length = 6+6+8; | |
370 | ||
371 | init_uni_h261_rl_tab(&ff_h261_rl_tcoeff, NULL, uni_h261_rl_len); | |
372 | ||
373 | s->intra_ac_vlc_length = s->inter_ac_vlc_length = uni_h261_rl_len; | |
374 | s->intra_ac_vlc_last_length = s->inter_ac_vlc_last_length = uni_h261_rl_len + 128*64; | |
375 | } | |
376 | ||
377 | FF_MPV_GENERIC_CLASS(h261) | |
378 | ||
379 | AVCodec ff_h261_encoder = { | |
380 | .name = "h261", | |
381 | .long_name = NULL_IF_CONFIG_SMALL("H.261"), | |
382 | .type = AVMEDIA_TYPE_VIDEO, | |
383 | .id = AV_CODEC_ID_H261, | |
384 | .priv_data_size = sizeof(H261Context), | |
385 | .init = ff_mpv_encode_init, | |
386 | .encode2 = ff_mpv_encode_picture, | |
387 | .close = ff_mpv_encode_end, | |
388 | .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, | |
389 | AV_PIX_FMT_NONE }, | |
390 | .priv_class = &h261_class, | |
391 | }; |