h261: Signal freeze picture release for intra frames
[libav.git] / libavcodec / h261enc.c
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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 *
2912e87a 6 * This file is part of Libav.
d632239c 7 *
2912e87a 8 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 13 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 19 * License along with Libav; if not, write to the Free Software
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20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
ba87f080 24 * @file
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25 * H.261 encoder.
26 */
27
6fee1b90 28#include "libavutil/attributes.h"
d632239c 29#include "avcodec.h"
e0c16e4e 30#include "mpegutils.h"
d632239c 31#include "mpegvideo.h"
06e03fa0 32#include "h263.h"
d632239c 33#include "h261.h"
378a0008 34#include "mpegvideodata.h"
d632239c 35
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36int ff_h261_get_picture_format(int width, int height)
37{
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38 // QCIF
39 if (width == 176 && height == 144)
40 return 0;
41 // CIF
42 else if (width == 352 && height == 288)
43 return 1;
44 // ERROR
45 else
46 return -1;
47}
48
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49void ff_h261_encode_picture_header(MpegEncContext *s, int picture_number)
50{
51 H261Context *h = (H261Context *)s;
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52 int format, temp_ref;
53
9f51c682 54 avpriv_align_put_bits(&s->pb);
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55
56 /* Update the pointer to last GOB */
fb53b4a0 57 s->ptr_lastgob = put_bits_ptr(&s->pb);
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58
59 put_bits(&s->pb, 20, 0x10); /* PSC */
60
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61 temp_ref = s->picture_number * (int64_t)30000 * s->avctx->time_base.num /
62 (1001 * (int64_t)s->avctx->time_base.den); // FIXME maybe this should use a timestamp
6647ab80 63 put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */
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64
65 put_bits(&s->pb, 1, 0); /* split screen off */
66 put_bits(&s->pb, 1, 0); /* camera off */
02b7c630 67 put_bits(&s->pb, 1, s->pict_type == AV_PICTURE_TYPE_I); /* freeze picture release on/off */
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68
69 format = ff_h261_get_picture_format(s->width, s->height);
70
71 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */
72
dc1de0b9
SS
73 put_bits(&s->pb, 1, 1); /* still image mode */
74 put_bits(&s->pb, 1, 1); /* reserved */
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75
76 put_bits(&s->pb, 1, 0); /* no PEI */
b78f81c8 77 if (format == 0)
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78 h->gob_number = -1;
79 else
80 h->gob_number = 0;
81 h->current_mba = 0;
82}
83
84/**
49bd8e4b 85 * Encode a group of blocks header.
d632239c 86 */
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87static void h261_encode_gob_header(MpegEncContext *s, int mb_line)
88{
89 H261Context *h = (H261Context *)s;
90 if (ff_h261_get_picture_format(s->width, s->height) == 0) {
91 h->gob_number += 2; // QCIF
92 } else {
93 h->gob_number++; // CIF
d632239c 94 }
b78f81c8 95 put_bits(&s->pb, 16, 1); /* GBSC */
d632239c 96 put_bits(&s->pb, 4, h->gob_number); /* GN */
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97 put_bits(&s->pb, 5, s->qscale); /* GQUANT */
98 put_bits(&s->pb, 1, 0); /* no GEI */
99 h->current_mba = 0;
d632239c 100 h->previous_mba = 0;
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101 h->current_mv_x = 0;
102 h->current_mv_y = 0;
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103}
104
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105void ff_h261_reorder_mb_index(MpegEncContext *s)
106{
107 int index = s->mb_x + s->mb_y * s->mb_width;
d632239c 108
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109 if (index % 33 == 0)
110 h261_encode_gob_header(s, 0);
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111
112 /* for CIF the GOB's are fragmented in the middle of a scanline
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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;
116 index /= 11;
117 s->mb_y = index % 3;
118 index /= 3;
119 s->mb_x += 11 * (index % 2);
120 index /= 2;
121 s->mb_y += 3 * index;
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122
123 ff_init_block_index(s);
124 ff_update_block_index(s);
125 }
126}
127
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128static void h261_encode_motion(H261Context *h, int val)
129{
130 MpegEncContext *const s = &h->s;
d632239c 131 int sign, code;
b78f81c8 132 if (val == 0) {
d632239c 133 code = 0;
8a776ad9 134 put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]);
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135 } else {
136 if (val > 15)
137 val -= 32;
138 if (val < -16)
139 val += 32;
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140 sign = val < 0;
141 code = sign ? -val : val;
8a776ad9 142 put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]);
b78f81c8 143 put_bits(&s->pb, 1, sign);
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144 }
145}
146
b78f81c8 147static inline int get_cbp(MpegEncContext *s, int16_t block[6][64])
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148{
149 int i, cbp;
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150 cbp = 0;
151 for (i = 0; i < 6; i++)
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152 if (s->block_last_index[i] >= 0)
153 cbp |= 1 << (5 - i);
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154 return cbp;
155}
b78f81c8 156
0404ec61
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157/**
158 * Encode an 8x8 block.
159 * @param block the 8x8 block
160 * @param n block index (0-3 are luma, 4-5 are chroma)
161 */
162static void h261_encode_block(H261Context *h, int16_t *block, int n)
163{
164 MpegEncContext *const s = &h->s;
165 int level, run, i, j, last_index, last_non_zero, sign, slevel, code;
166 RLTable *rl;
167
8a776ad9 168 rl = &ff_h261_rl_tcoeff;
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169 if (s->mb_intra) {
170 /* DC coef */
171 level = block[0];
172 /* 255 cannot be represented, so we clamp */
173 if (level > 254) {
174 level = 254;
175 block[0] = 254;
176 }
177 /* 0 cannot be represented also */
178 else if (level < 1) {
179 level = 1;
180 block[0] = 1;
181 }
182 if (level == 128)
183 put_bits(&s->pb, 8, 0xff);
184 else
185 put_bits(&s->pb, 8, level);
186 i = 1;
187 } else if ((block[0] == 1 || block[0] == -1) &&
188 (s->block_last_index[n] > -1)) {
189 // special case
190 put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3);
191 i = 1;
192 } else {
193 i = 0;
194 }
195
196 /* AC coefs */
197 last_index = s->block_last_index[n];
198 last_non_zero = i - 1;
199 for (; i <= last_index; i++) {
200 j = s->intra_scantable.permutated[i];
201 level = block[j];
202 if (level) {
203 run = i - last_non_zero - 1;
204 sign = 0;
205 slevel = level;
206 if (level < 0) {
207 sign = 1;
208 level = -level;
209 }
210 code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/,
211 run, level);
212 if (run == 0 && level < 16)
213 code += 1;
214 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
215 if (code == rl->n) {
216 put_bits(&s->pb, 6, run);
217 assert(slevel != 0);
218 assert(level <= 127);
219 put_sbits(&s->pb, 8, slevel);
220 } else {
221 put_bits(&s->pb, 1, sign);
222 }
223 last_non_zero = i;
224 }
225 }
226 if (last_index > -1)
227 put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]); // EOB
228}
229
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230void ff_h261_encode_mb(MpegEncContext *s, int16_t block[6][64],
231 int motion_x, int motion_y)
d632239c 232{
b78f81c8 233 H261Context *h = (H261Context *)s;
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234 int mvd, mv_diff_x, mv_diff_y, i, cbp;
235 cbp = 63; // avoid warning
236 mvd = 0;
237
238 h->current_mba++;
239 h->mtype = 0;
240
b78f81c8 241 if (!s->mb_intra) {
d632239c 242 /* compute cbp */
b78f81c8 243 cbp = get_cbp(s, block);
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244
245 /* mvd indicates if this block is motion compensated */
246 mvd = motion_x | motion_y;
247
b78f81c8 248 if ((cbp | mvd | s->dquant) == 0) {
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249 /* skip macroblock */
250 s->skip_count++;
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251 h->current_mv_x = 0;
252 h->current_mv_y = 0;
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253 return;
254 }
255 }
256
257 /* MB is not skipped, encode MBA */
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258 put_bits(&s->pb,
259 ff_h261_mba_bits[(h->current_mba - h->previous_mba) - 1],
260 ff_h261_mba_code[(h->current_mba - h->previous_mba) - 1]);
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261
262 /* calculate MTYPE */
b78f81c8 263 if (!s->mb_intra) {
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264 h->mtype++;
265
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266 if (mvd || s->loop_filter)
267 h->mtype += 3;
268 if (s->loop_filter)
269 h->mtype += 3;
270 if (cbp || s->dquant)
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271 h->mtype++;
272 assert(h->mtype > 1);
273 }
274
b78f81c8 275 if (s->dquant)
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276 h->mtype++;
277
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278 put_bits(&s->pb,
279 ff_h261_mtype_bits[h->mtype],
280 ff_h261_mtype_code[h->mtype]);
d632239c 281
8a776ad9 282 h->mtype = ff_h261_mtype_map[h->mtype];
d632239c 283
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284 if (IS_QUANT(h->mtype)) {
285 ff_set_qscale(s, s->qscale + s->dquant);
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286 put_bits(&s->pb, 5, s->qscale);
287 }
288
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289 if (IS_16X16(h->mtype)) {
290 mv_diff_x = (motion_x >> 1) - h->current_mv_x;
291 mv_diff_y = (motion_y >> 1) - h->current_mv_y;
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292 h->current_mv_x = (motion_x >> 1);
293 h->current_mv_y = (motion_y >> 1);
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294 h261_encode_motion(h, mv_diff_x);
295 h261_encode_motion(h, mv_diff_y);
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296 }
297
298 h->previous_mba = h->current_mba;
299
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300 if (HAS_CBP(h->mtype)) {
301 assert(cbp > 0);
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302 put_bits(&s->pb,
303 ff_h261_cbp_tab[cbp - 1][1],
304 ff_h261_cbp_tab[cbp - 1][0]);
d632239c 305 }
b78f81c8 306 for (i = 0; i < 6; i++)
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307 /* encode each block */
308 h261_encode_block(h, block[i], i);
d632239c 309
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310 if ((h->current_mba == 11) || (h->current_mba == 22) ||
311 (h->current_mba == 33) || (!IS_16X16(h->mtype))) {
312 h->current_mv_x = 0;
313 h->current_mv_y = 0;
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314 }
315}
316
6fee1b90 317av_cold void ff_h261_encode_init(MpegEncContext *s)
b78f81c8 318{
20429ba9 319 ff_h261_common_init();
d632239c 320
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321 s->min_qcoeff = -127;
322 s->max_qcoeff = 127;
323 s->y_dc_scale_table =
324 s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
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325}
326
f1fa1eed
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327static const AVClass h261_class = {
328 .class_name = "h261 encoder",
329 .item_name = av_default_item_name,
330 .option = ff_mpv_generic_options,
331 .version = LIBAVUTIL_VERSION_INT,
332};
ed019b8e 333
d36beb3f 334AVCodec ff_h261_encoder = {
ec6402b7 335 .name = "h261",
b2bed932 336 .long_name = NULL_IF_CONFIG_SMALL("H.261"),
ec6402b7 337 .type = AVMEDIA_TYPE_VIDEO,
36ef5369 338 .id = AV_CODEC_ID_H261,
ec6402b7 339 .priv_data_size = sizeof(H261Context),
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340 .init = ff_mpv_encode_init,
341 .encode2 = ff_mpv_encode_picture,
342 .close = ff_mpv_encode_end,
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343 .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
344 AV_PIX_FMT_NONE },
ed019b8e 345 .priv_class = &h261_class,
d632239c 346};