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
29 #include "mpegvideo.h"
34 static void h261_encode_block(H261Context *h, int16_t *block,
37 int ff_h261_get_picture_format(int width, int height)
40 if (width == 176 && height == 144)
43 else if (width == 352 && height == 288)
50 void ff_h261_encode_picture_header(MpegEncContext *s, int picture_number)
52 H261Context *h = (H261Context *)s;
55 avpriv_align_put_bits(&s->pb);
57 /* Update the pointer to last GOB */
58 s->ptr_lastgob = put_bits_ptr(&s->pb);
60 put_bits(&s->pb, 20, 0x10); /* PSC */
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_sbits(&s->pb, 5, temp_ref); /* TemporalReference */
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 */
70 format = ff_h261_get_picture_format(s->width, s->height);
72 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */
74 put_bits(&s->pb, 1, 0); /* still image mode */
75 put_bits(&s->pb, 1, 0); /* reserved */
77 put_bits(&s->pb, 1, 0); /* no PEI */
86 * Encode a group of blocks header.
88 static void h261_encode_gob_header(MpegEncContext *s, int mb_line)
90 H261Context *h = (H261Context *)s;
91 if (ff_h261_get_picture_format(s->width, s->height) == 0) {
92 h->gob_number += 2; // QCIF
94 h->gob_number++; // CIF
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 */
106 void ff_h261_reorder_mb_index(MpegEncContext *s)
108 int index = s->mb_x + s->mb_y * s->mb_width;
111 h261_encode_gob_header(s, 0);
113 /* for CIF the GOB's are fragmented in the middle of a scanline
114 * that's why we need to adjust the x and y index of the macroblocks */
115 if (ff_h261_get_picture_format(s->width, s->height) == 1) { // CIF
116 s->mb_x = index % 11;
120 s->mb_x += 11 * (index % 2);
122 s->mb_y += 3 * index;
124 ff_init_block_index(s);
125 ff_update_block_index(s);
129 static void h261_encode_motion(H261Context *h, int val)
131 MpegEncContext *const s = &h->s;
135 put_bits(&s->pb, h261_mv_tab[code][1], h261_mv_tab[code][0]);
142 code = sign ? -val : val;
143 put_bits(&s->pb, h261_mv_tab[code][1], h261_mv_tab[code][0]);
144 put_bits(&s->pb, 1, sign);
148 static inline int get_cbp(MpegEncContext *s, int16_t block[6][64])
152 for (i = 0; i < 6; i++)
153 if (s->block_last_index[i] >= 0)
158 void ff_h261_encode_mb(MpegEncContext *s, int16_t block[6][64],
159 int motion_x, int motion_y)
161 H261Context *h = (H261Context *)s;
162 int mvd, mv_diff_x, mv_diff_y, i, cbp;
163 cbp = 63; // avoid warning
171 cbp = get_cbp(s, block);
173 /* mvd indicates if this block is motion compensated */
174 mvd = motion_x | motion_y;
176 if ((cbp | mvd | s->dquant) == 0) {
177 /* skip macroblock */
185 /* MB is not skipped, encode MBA */
186 put_bits(&s->pb, h261_mba_bits[(h->current_mba - h->previous_mba) - 1],
187 h261_mba_code[(h->current_mba - h->previous_mba) - 1]);
189 /* calculate MTYPE */
193 if (mvd || s->loop_filter)
197 if (cbp || s->dquant)
199 assert(h->mtype > 1);
205 put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]);
207 h->mtype = h261_mtype_map[h->mtype];
209 if (IS_QUANT(h->mtype)) {
210 ff_set_qscale(s, s->qscale + s->dquant);
211 put_bits(&s->pb, 5, s->qscale);
214 if (IS_16X16(h->mtype)) {
215 mv_diff_x = (motion_x >> 1) - h->current_mv_x;
216 mv_diff_y = (motion_y >> 1) - h->current_mv_y;
217 h->current_mv_x = (motion_x >> 1);
218 h->current_mv_y = (motion_y >> 1);
219 h261_encode_motion(h, mv_diff_x);
220 h261_encode_motion(h, mv_diff_y);
223 h->previous_mba = h->current_mba;
225 if (HAS_CBP(h->mtype)) {
227 put_bits(&s->pb, h261_cbp_tab[cbp - 1][1], h261_cbp_tab[cbp - 1][0]);
229 for (i = 0; i < 6; i++)
230 /* encode each block */
231 h261_encode_block(h, block[i], i);
233 if ((h->current_mba == 11) || (h->current_mba == 22) ||
234 (h->current_mba == 33) || (!IS_16X16(h->mtype))) {
240 void ff_h261_encode_init(MpegEncContext *s)
246 ff_init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store);
249 s->min_qcoeff = -127;
251 s->y_dc_scale_table =
252 s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
256 * Encode an 8x8 block.
257 * @param block the 8x8 block
258 * @param n block index (0-3 are luma, 4-5 are chroma)
260 static void h261_encode_block(H261Context *h, int16_t *block, int n)
262 MpegEncContext *const s = &h->s;
263 int level, run, i, j, last_index, last_non_zero, sign, slevel, code;
266 rl = &h261_rl_tcoeff;
270 /* 255 cannot be represented, so we clamp */
275 /* 0 cannot be represented also */
276 else if (level < 1) {
281 put_bits(&s->pb, 8, 0xff);
283 put_bits(&s->pb, 8, level);
285 } else if ((block[0] == 1 || block[0] == -1) &&
286 (s->block_last_index[n] > -1)) {
288 put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3);
295 last_index = s->block_last_index[n];
296 last_non_zero = i - 1;
297 for (; i <= last_index; i++) {
298 j = s->intra_scantable.permutated[i];
301 run = i - last_non_zero - 1;
308 code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/,
310 if (run == 0 && level < 16)
312 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
314 put_bits(&s->pb, 6, run);
316 assert(level <= 127);
317 put_sbits(&s->pb, 8, slevel);
319 put_bits(&s->pb, 1, sign);
325 put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]); // EOB
328 FF_MPV_GENERIC_CLASS(h261)
330 AVCodec ff_h261_encoder = {
332 .type = AVMEDIA_TYPE_VIDEO,
333 .id = AV_CODEC_ID_H261,
334 .priv_data_size = sizeof(H261Context),
335 .init = ff_MPV_encode_init,
336 .encode2 = ff_MPV_encode_picture,
337 .close = ff_MPV_encode_end,
338 .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
340 .long_name = NULL_IF_CONFIG_SMALL("H.261"),
341 .priv_class = &h261_class,