3 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2004 Maarten Daniels
6 * This file is part of Libav.
8 * Libav 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.
13 * Libav 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.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 #include "libavutil/attributes.h"
30 #include "mpegutils.h"
31 #include "mpegvideo.h"
34 #include "mpegvideodata.h"
36 int ff_h261_get_picture_format(int width, int height)
39 if (width == 176 && height == 144)
42 else if (width == 352 && height == 288)
49 void ff_h261_encode_picture_header(MpegEncContext *s, int picture_number)
51 H261Context *h = (H261Context *)s;
54 avpriv_align_put_bits(&s->pb);
56 /* Update the pointer to last GOB */
57 s->ptr_lastgob = put_bits_ptr(&s->pb);
59 put_bits(&s->pb, 20, 0x10); /* PSC */
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
63 put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */
65 put_bits(&s->pb, 1, 0); /* split screen off */
66 put_bits(&s->pb, 1, 0); /* camera off */
67 put_bits(&s->pb, 1, s->pict_type == AV_PICTURE_TYPE_I); /* freeze picture release on/off */
69 format = ff_h261_get_picture_format(s->width, s->height);
71 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */
73 put_bits(&s->pb, 1, 1); /* still image mode */
74 put_bits(&s->pb, 1, 1); /* reserved */
76 put_bits(&s->pb, 1, 0); /* no PEI */
85 * Encode a group of blocks header.
87 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
93 h->gob_number++; // CIF
95 put_bits(&s->pb, 16, 1); /* GBSC */
96 put_bits(&s->pb, 4, h->gob_number); /* GN */
97 put_bits(&s->pb, 5, s->qscale); /* GQUANT */
98 put_bits(&s->pb, 1, 0); /* no GEI */
105 void ff_h261_reorder_mb_index(MpegEncContext *s)
107 int index = s->mb_x + s->mb_y * s->mb_width;
110 h261_encode_gob_header(s, 0);
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;
119 s->mb_x += 11 * (index % 2);
121 s->mb_y += 3 * index;
123 ff_init_block_index(s);
124 ff_update_block_index(s);
128 static void h261_encode_motion(H261Context *h, int val)
130 MpegEncContext *const s = &h->s;
134 put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]);
141 code = sign ? -val : val;
142 put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]);
143 put_bits(&s->pb, 1, sign);
147 static inline int get_cbp(MpegEncContext *s, int16_t block[6][64])
151 for (i = 0; i < 6; i++)
152 if (s->block_last_index[i] >= 0)
158 * Encode an 8x8 block.
159 * @param block the 8x8 block
160 * @param n block index (0-3 are luma, 4-5 are chroma)
162 static void h261_encode_block(H261Context *h, int16_t *block, int n)
164 MpegEncContext *const s = &h->s;
165 int level, run, i, j, last_index, last_non_zero, sign, slevel, code;
168 rl = &ff_h261_rl_tcoeff;
172 /* 255 cannot be represented, so we clamp */
177 /* 0 cannot be represented also */
178 else if (level < 1) {
183 put_bits(&s->pb, 8, 0xff);
185 put_bits(&s->pb, 8, level);
187 } else if ((block[0] == 1 || block[0] == -1) &&
188 (s->block_last_index[n] > -1)) {
190 put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3);
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];
203 run = i - last_non_zero - 1;
210 code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/,
212 if (run == 0 && level < 16)
214 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
216 put_bits(&s->pb, 6, run);
218 assert(level <= 127);
219 put_sbits(&s->pb, 8, slevel);
221 put_bits(&s->pb, 1, sign);
227 put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]); // EOB
230 void ff_h261_encode_mb(MpegEncContext *s, int16_t block[6][64],
231 int motion_x, int motion_y)
233 H261Context *h = (H261Context *)s;
234 int mvd, mv_diff_x, mv_diff_y, i, cbp;
235 cbp = 63; // avoid warning
243 cbp = get_cbp(s, block);
245 /* mvd indicates if this block is motion compensated */
246 mvd = motion_x | motion_y;
248 if ((cbp | mvd | s->dquant) == 0) {
249 /* skip macroblock */
257 /* MB is not skipped, encode MBA */
259 ff_h261_mba_bits[(h->current_mba - h->previous_mba) - 1],
260 ff_h261_mba_code[(h->current_mba - h->previous_mba) - 1]);
262 /* calculate MTYPE */
266 if (mvd || s->loop_filter)
270 if (cbp || s->dquant)
272 assert(h->mtype > 1);
279 ff_h261_mtype_bits[h->mtype],
280 ff_h261_mtype_code[h->mtype]);
282 h->mtype = ff_h261_mtype_map[h->mtype];
284 if (IS_QUANT(h->mtype)) {
285 ff_set_qscale(s, s->qscale + s->dquant);
286 put_bits(&s->pb, 5, s->qscale);
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;
292 h->current_mv_x = (motion_x >> 1);
293 h->current_mv_y = (motion_y >> 1);
294 h261_encode_motion(h, mv_diff_x);
295 h261_encode_motion(h, mv_diff_y);
298 h->previous_mba = h->current_mba;
300 if (HAS_CBP(h->mtype)) {
303 ff_h261_cbp_tab[cbp - 1][1],
304 ff_h261_cbp_tab[cbp - 1][0]);
306 for (i = 0; i < 6; i++)
307 /* encode each block */
308 h261_encode_block(h, block[i], i);
310 if ((h->current_mba == 11) || (h->current_mba == 22) ||
311 (h->current_mba == 33) || (!IS_16X16(h->mtype))) {
317 av_cold void ff_h261_encode_init(MpegEncContext *s)
319 ff_h261_common_init();
321 s->min_qcoeff = -127;
323 s->y_dc_scale_table =
324 s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
327 static 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,
334 AVCodec ff_h261_encoder = {
336 .long_name = NULL_IF_CONFIG_SMALL("H.261"),
337 .type = AVMEDIA_TYPE_VIDEO,
338 .id = AV_CODEC_ID_H261,
339 .priv_data_size = sizeof(H261Context),
340 .init = ff_mpv_encode_init,
341 .encode2 = ff_mpv_encode_picture,
342 .close = ff_mpv_encode_end,
343 .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
345 .priv_class = &h261_class,