FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/h261dec.c
Date: 2021-09-24 20:55:06
Exec Total Coverage
Lines: 264 330 80.0%
Branches: 116 178 65.2%

Line Branch Exec Source
1 /*
2 * H.261 decoder
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 decoder.
26 */
27
28 #include "libavutil/avassert.h"
29 #include "libavutil/thread.h"
30 #include "avcodec.h"
31 #include "mpeg_er.h"
32 #include "mpegutils.h"
33 #include "mpegvideo.h"
34 #include "h263.h"
35 #include "h261.h"
36 #include "internal.h"
37
38 #define H261_MBA_VLC_BITS 8
39 #define H261_MTYPE_VLC_BITS 6
40 #define H261_MV_VLC_BITS 7
41 #define H261_CBP_VLC_BITS 9
42 #define TCOEFF_VLC_BITS 9
43 #define MBA_STUFFING 33
44 #define MBA_STARTCODE 34
45
46 static VLC h261_mba_vlc;
47 static VLC h261_mtype_vlc;
48 static VLC h261_mv_vlc;
49 static VLC h261_cbp_vlc;
50
51 7 static av_cold void h261_decode_init_static(void)
52 {
53 7 INIT_VLC_STATIC(&h261_mba_vlc, H261_MBA_VLC_BITS, 35,
54 ff_h261_mba_bits, 1, 1,
55 ff_h261_mba_code, 1, 1, 540);
56 7 INIT_VLC_STATIC(&h261_mtype_vlc, H261_MTYPE_VLC_BITS, 10,
57 ff_h261_mtype_bits, 1, 1,
58 ff_h261_mtype_code, 1, 1, 80);
59 7 INIT_VLC_STATIC(&h261_mv_vlc, H261_MV_VLC_BITS, 17,
60 &ff_h261_mv_tab[0][1], 2, 1,
61 &ff_h261_mv_tab[0][0], 2, 1, 144);
62 7 INIT_VLC_STATIC(&h261_cbp_vlc, H261_CBP_VLC_BITS, 63,
63 &ff_h261_cbp_tab[0][1], 2, 1,
64 &ff_h261_cbp_tab[0][0], 2, 1, 512);
65 7 INIT_FIRST_VLC_RL(ff_h261_rl_tcoeff, 552);
66 7 }
67
68 13 static av_cold int h261_decode_init(AVCodecContext *avctx)
69 {
70 static AVOnce init_static_once = AV_ONCE_INIT;
71 13 H261Context *h = avctx->priv_data;
72 13 MpegEncContext *const s = &h->s;
73
74 // set defaults
75 13 ff_mpv_decode_init(s, avctx);
76
77 13 s->out_format = FMT_H261;
78 13 s->low_delay = 1;
79 13 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
80
81 13 h->gob_start_code_skipped = 0;
82 13 ff_mpv_idct_init(s);
83
84 13 ff_thread_once(&init_static_once, h261_decode_init_static);
85
86 13 return 0;
87 }
88
89 /**
90 * Decode the group of blocks header or slice header.
91 * @return <0 if an error occurred
92 */
93 3600 static int h261_decode_gob_header(H261Context *h)
94 {
95 unsigned int val;
96 3600 MpegEncContext *const s = &h->s;
97
98
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3600 if (!h->gob_start_code_skipped) {
99 /* Check for GOB Start Code */
100 300 val = show_bits(&s->gb, 15);
101
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300 if (val)
102 return -1;
103
104 /* We have a GBSC */
105 300 skip_bits(&s->gb, 16);
106 }
107
108 3600 h->gob_start_code_skipped = 0;
109
110 3600 h->gob_number = get_bits(&s->gb, 4); /* GN */
111 3600 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
112
113 /* Check if gob_number is valid */
114
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3600 if (s->mb_height == 18) { // CIF
115
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3600 if ((h->gob_number <= 0) || (h->gob_number > 12))
116 return -1;
117 } else { // QCIF
118 if ((h->gob_number != 1) && (h->gob_number != 3) &&
119 (h->gob_number != 5))
120 return -1;
121 }
122
123 /* GEI */
124
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3600 if (skip_1stop_8data_bits(&s->gb) < 0)
125 return AVERROR_INVALIDDATA;
126
127
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3600 if (s->qscale == 0) {
128 av_log(s->avctx, AV_LOG_ERROR, "qscale has forbidden 0 value\n");
129 if (s->avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_COMPLIANT))
130 return -1;
131 }
132
133 /* For the first transmitted macroblock in a GOB, MBA is the absolute
134 * address. For subsequent macroblocks, MBA is the difference between
135 * the absolute addresses of the macroblock and the last transmitted
136 * macroblock. */
137 3600 h->current_mba = 0;
138 3600 h->mba_diff = 0;
139
140 3600 return 0;
141 }
142
143 /**
144 * Decode the group of blocks / video packet header.
145 * @return <0 if no resync found
146 */
147 3600 static int h261_resync(H261Context *h)
148 {
149 3600 MpegEncContext *const s = &h->s;
150 int left, ret;
151
152
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3600 if (h->gob_start_code_skipped) {
153 3300 ret = h261_decode_gob_header(h);
154
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3300 if (ret >= 0)
155 3300 return 0;
156 } else {
157
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300 if (show_bits(&s->gb, 15) == 0) {
158 300 ret = h261_decode_gob_header(h);
159
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300 if (ret >= 0)
160 300 return 0;
161 }
162 // OK, it is not where it is supposed to be ...
163 s->gb = s->last_resync_gb;
164 align_get_bits(&s->gb);
165 left = get_bits_left(&s->gb);
166
167 for (; left > 15 + 1 + 4 + 5; left -= 8) {
168 if (show_bits(&s->gb, 15) == 0) {
169 GetBitContext bak = s->gb;
170
171 ret = h261_decode_gob_header(h);
172 if (ret >= 0)
173 return 0;
174
175 s->gb = bak;
176 }
177 skip_bits(&s->gb, 8);
178 }
179 }
180
181 return -1;
182 }
183
184 /**
185 * Decode skipped macroblocks.
186 * @return 0
187 */
188 121514 static int h261_decode_mb_skipped(H261Context *h, int mba1, int mba2)
189 {
190 121514 MpegEncContext *const s = &h->s;
191 int i;
192
193 121514 s->mb_intra = 0;
194
195
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122400 for (i = mba1; i < mba2; i++) {
196 int j, xy;
197
198 886 s->mb_x = ((h->gob_number - 1) % 2) * 11 + i % 11;
199 886 s->mb_y = ((h->gob_number - 1) / 2) * 3 + i / 11;
200 886 xy = s->mb_x + s->mb_y * s->mb_stride;
201 886 ff_init_block_index(s);
202 886 ff_update_block_index(s);
203
204
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6202 for (j = 0; j < 6; j++)
205 5316 s->block_last_index[j] = -1;
206
207 886 s->mv_dir = MV_DIR_FORWARD;
208 886 s->mv_type = MV_TYPE_16X16;
209 886 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
210 886 s->mv[0][0][0] = 0;
211 886 s->mv[0][0][1] = 0;
212 886 s->mb_skipped = 1;
213 886 h->mtype &= ~MB_TYPE_H261_FIL;
214
215
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886 if (s->current_picture.motion_val[0]) {
216 int b_stride = 2*s->mb_width + 1;
217 int b_xy = 2 * s->mb_x + (2 * s->mb_y) * b_stride;
218 s->current_picture.motion_val[0][b_xy][0] = s->mv[0][0][0];
219 s->current_picture.motion_val[0][b_xy][1] = s->mv[0][0][1];
220 }
221
222 886 ff_mpv_reconstruct_mb(s, s->block);
223 }
224
225 121514 return 0;
226 }
227
228 static const int mvmap[17] = {
229 0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16
230 };
231
232 193928 static int decode_mv_component(GetBitContext *gb, int v)
233 {
234 193928 int mv_diff = get_vlc2(gb, h261_mv_vlc.table, H261_MV_VLC_BITS, 2);
235
236 /* check if mv_diff is valid */
237
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193928 if (mv_diff < 0)
238 return v;
239
240 193928 mv_diff = mvmap[mv_diff];
241
242
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193928 if (mv_diff && !get_bits1(gb))
243 37209 mv_diff = -mv_diff;
244
245 193928 v += mv_diff;
246
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193928 if (v <= -16)
247 36 v += 32;
248
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193892 else if (v >= 16)
249 30 v -= 32;
250
251 193928 return v;
252 }
253
254 /**
255 * Decode a macroblock.
256 * @return <0 if an error occurred
257 */
258 590082 static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
259 {
260 590082 MpegEncContext *const s = &h->s;
261 int level, i, j, run;
262 590082 RLTable *rl = &ff_h261_rl_tcoeff;
263 const uint8_t *scan_table;
264
265 /* For the variable length encoding there are two code tables, one being
266 * used for the first transmitted LEVEL in INTER, INTER + MC and
267 * INTER + MC + FIL blocks, the second for all other LEVELs except the
268 * first one in INTRA blocks which is fixed length coded with 8 bits.
269 * NOTE: The two code tables only differ in one VLC so we handle that
270 * manually. */
271 590082 scan_table = s->intra_scantable.permutated;
272
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590082 if (s->mb_intra) {
273 /* DC coef */
274 106194 level = get_bits(&s->gb, 8);
275 // 0 (00000000b) and -128 (10000000b) are FORBIDDEN
276
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106194 if ((level & 0x7F) == 0) {
277 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n",
278 level, s->mb_x, s->mb_y);
279 return -1;
280 }
281 /* The code 1000 0000 is not used, the reconstruction level of 1024
282 * being coded as 1111 1111. */
283
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106194 if (level == 255)
284 1211 level = 128;
285 106194 block[0] = level;
286 106194 i = 1;
287
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483888 } else if (coded) {
288 // Run Level Code
289 // EOB Not possible for first level when cbp is available (that's why the table is different)
290 // 0 1 1s
291 // * * 0*
292 242540 int check = show_bits(&s->gb, 2);
293 242540 i = 0;
294
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242540 if (check & 0x2) {
295 81615 skip_bits(&s->gb, 2);
296
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81615 block[0] = (check & 0x1) ? -1 : 1;
297 81615 i = 1;
298 }
299 } else {
300 241348 i = 0;
301 }
302
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590082 if (!coded) {
303 241348 s->block_last_index[n] = i - 1;
304 241348 return 0;
305 }
306 {
307 348734 OPEN_READER(re, &s->gb);
308 348734 i--; // offset by -1 to allow direct indexing of scan_table
309 for (;;) {
310 2586037 UPDATE_CACHE(re, &s->gb);
311
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2586037 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TCOEFF_VLC_BITS, 2, 0);
312
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2586037 if (run == 66) {
313
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65180 if (level) {
314 CLOSE_READER(re, &s->gb);
315 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n",
316 s->mb_x, s->mb_y);
317 return -1;
318 }
319 /* escape */
320 /* The remaining combinations of (run, level) are encoded with a
321 * 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
322 * level. */
323 65180 run = SHOW_UBITS(re, &s->gb, 6) + 1;
324 65180 SKIP_CACHE(re, &s->gb, 6);
325 65180 level = SHOW_SBITS(re, &s->gb, 8);
326 65180 SKIP_COUNTER(re, &s->gb, 6 + 8);
327
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2520857 } else if (level == 0) {
328 348734 break;
329 } else {
330
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2172123 if (SHOW_UBITS(re, &s->gb, 1))
331 1087153 level = -level;
332 2172123 SKIP_COUNTER(re, &s->gb, 1);
333 }
334 2237303 i += run;
335
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2237303 if (i >= 64) {
336 CLOSE_READER(re, &s->gb);
337 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n",
338 s->mb_x, s->mb_y);
339 return -1;
340 }
341 2237303 j = scan_table[i];
342 2237303 block[j] = level;
343 }
344 348734 CLOSE_READER(re, &s->gb);
345 }
346 348734 s->block_last_index[n] = i;
347 348734 return 0;
348 }
349
350 121514 static int h261_decode_mb(H261Context *h)
351 {
352 121514 MpegEncContext *const s = &h->s;
353 int i, cbp, xy;
354
355 121514 cbp = 63;
356 // Read mba
357 do {
358 121514 h->mba_diff = get_vlc2(&s->gb, h261_mba_vlc.table,
359 H261_MBA_VLC_BITS, 2);
360
361 /* Check for slice end */
362 /* NOTE: GOB can be empty (no MB data) or exist only of MBA_stuffing */
363
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121514 if (h->mba_diff == MBA_STARTCODE) { // start code
364 3300 h->gob_start_code_skipped = 1;
365 3300 return SLICE_END;
366 }
367
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118214 } while (h->mba_diff == MBA_STUFFING); // stuffing
368
369
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118214 if (h->mba_diff < 0) {
370
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300 if (get_bits_left(&s->gb) <= 7)
371 300 return SLICE_END;
372
373 av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y);
374 return SLICE_ERROR;
375 }
376
377 117914 h->mba_diff += 1;
378 117914 h->current_mba += h->mba_diff;
379
380
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117914 if (h->current_mba > MBA_STUFFING)
381 return SLICE_ERROR;
382
383 117914 s->mb_x = ((h->gob_number - 1) % 2) * 11 + ((h->current_mba - 1) % 11);
384 117914 s->mb_y = ((h->gob_number - 1) / 2) * 3 + ((h->current_mba - 1) / 11);
385 117914 xy = s->mb_x + s->mb_y * s->mb_stride;
386 117914 ff_init_block_index(s);
387 117914 ff_update_block_index(s);
388
389 // Read mtype
390 117914 h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
391
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117914 if (h->mtype < 0) {
392 av_log(s->avctx, AV_LOG_ERROR, "Invalid mtype index %d\n",
393 h->mtype);
394 return SLICE_ERROR;
395 }
396
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117914 av_assert0(h->mtype < FF_ARRAY_ELEMS(ff_h261_mtype_map));
397 117914 h->mtype = ff_h261_mtype_map[h->mtype];
398
399 // Read mquant
400
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117914 if (IS_QUANT(h->mtype))
401 ff_set_qscale(s, get_bits(&s->gb, 5));
402
403 117914 s->mb_intra = IS_INTRA4x4(h->mtype);
404
405 // Read mv
406
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117914 if (IS_16X16(h->mtype)) {
407 /* Motion vector data is included for all MC macroblocks. MVD is
408 * obtained from the macroblock vector by subtracting the vector
409 * of the preceding macroblock. For this calculation the vector
410 * of the preceding macroblock is regarded as zero in the
411 * following three situations:
412 * 1) evaluating MVD for macroblocks 1, 12 and 23;
413 * 2) evaluating MVD for macroblocks in which MBA does not represent a difference of 1;
414 * 3) MTYPE of the previous macroblock was not MC. */
415
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96964 if ((h->current_mba == 1) || (h->current_mba == 12) ||
416
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91569 (h->current_mba == 23) || (h->mba_diff != 1)) {
417 8682 h->current_mv_x = 0;
418 8682 h->current_mv_y = 0;
419 }
420
421 96964 h->current_mv_x = decode_mv_component(&s->gb, h->current_mv_x);
422 96964 h->current_mv_y = decode_mv_component(&s->gb, h->current_mv_y);
423 } else {
424 20950 h->current_mv_x = 0;
425 20950 h->current_mv_y = 0;
426 }
427
428 // Read cbp
429
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117914 if (HAS_CBP(h->mtype))
430 80648 cbp = get_vlc2(&s->gb, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 1) + 1;
431
432
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117914 if (s->mb_intra) {
433 17699 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
434 17699 goto intra;
435 }
436
437 //set motion vectors
438 100215 s->mv_dir = MV_DIR_FORWARD;
439 100215 s->mv_type = MV_TYPE_16X16;
440 100215 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
441 100215 s->mv[0][0][0] = h->current_mv_x * 2; // gets divided by 2 in motion compensation
442 100215 s->mv[0][0][1] = h->current_mv_y * 2;
443
444
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100215 if (s->current_picture.motion_val[0]) {
445 int b_stride = 2*s->mb_width + 1;
446 int b_xy = 2 * s->mb_x + (2 * s->mb_y) * b_stride;
447 s->current_picture.motion_val[0][b_xy][0] = s->mv[0][0][0];
448 s->current_picture.motion_val[0][b_xy][1] = s->mv[0][0][1];
449 }
450
451 100215 intra:
452 /* decode each block */
453
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117914 if (s->mb_intra || HAS_CBP(h->mtype)) {
454 98347 s->bdsp.clear_blocks(s->block[0]);
455
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688429 for (i = 0; i < 6; i++) {
456
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590082 if (h261_decode_block(h, s->block[i], i, cbp & 32) < 0)
457 return SLICE_ERROR;
458 590082 cbp += cbp;
459 }
460 } else {
461
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136969 for (i = 0; i < 6; i++)
462 117402 s->block_last_index[i] = -1;
463 }
464
465 117914 ff_mpv_reconstruct_mb(s, s->block);
466
467 117914 return SLICE_OK;
468 }
469
470 /**
471 * Decode the H.261 picture header.
472 * @return <0 if no startcode found
473 */
474 306 static int h261_decode_picture_header(H261Context *h)
475 {
476 306 MpegEncContext *const s = &h->s;
477 int format, i;
478 306 uint32_t startcode = 0;
479
480
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6120 for (i = get_bits_left(&s->gb); i > 24; i -= 1) {
481 6120 startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;
482
483
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6120 if (startcode == 0x10)
484 306 break;
485 }
486
487
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306 if (startcode != 0x10) {
488 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
489 return -1;
490 }
491
492 /* temporal reference */
493 306 i = get_bits(&s->gb, 5); /* picture timestamp */
494
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306 if (i < (s->picture_number & 31))
495 6 i += 32;
496 306 s->picture_number = (s->picture_number & ~31) + i;
497
498 306 s->avctx->framerate = (AVRational) { 30000, 1001 };
499
500 /* PTYPE starts here */
501 306 skip_bits1(&s->gb); /* split screen off */
502 306 skip_bits1(&s->gb); /* camera off */
503 306 skip_bits1(&s->gb); /* freeze picture release off */
504
505 306 format = get_bits1(&s->gb);
506
507 // only 2 formats possible
508
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306 if (format == 0) { // QCIF
509 s->width = 176;
510 s->height = 144;
511 s->mb_width = 11;
512 s->mb_height = 9;
513 } else { // CIF
514 306 s->width = 352;
515 306 s->height = 288;
516 306 s->mb_width = 22;
517 306 s->mb_height = 18;
518 }
519
520 306 s->mb_num = s->mb_width * s->mb_height;
521
522 306 skip_bits1(&s->gb); /* still image mode off */
523 306 skip_bits1(&s->gb); /* Reserved */
524
525 /* PEI */
526
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306 if (skip_1stop_8data_bits(&s->gb) < 0)
527 return AVERROR_INVALIDDATA;
528
529 /* H.261 has no I-frames, but if we pass AV_PICTURE_TYPE_I for the first
530 * frame, the codec crashes if it does not contain all I-blocks
531 * (e.g. when a packet is lost). */
532 306 s->pict_type = AV_PICTURE_TYPE_P;
533
534 306 h->gob_number = 0;
535 306 return 0;
536 }
537
538 3600 static int h261_decode_gob(H261Context *h)
539 {
540 3600 MpegEncContext *const s = &h->s;
541
542 3600 ff_set_qscale(s, s->qscale);
543
544 /* decode mb's */
545
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121514 while (h->current_mba <= MBA_STUFFING) {
546 int ret;
547 /* DCT & quantize */
548 121514 ret = h261_decode_mb(h);
549
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121514 if (ret < 0) {
550
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3600 if (ret == SLICE_END) {
551 3600 h261_decode_mb_skipped(h, h->current_mba, 33);
552 3600 return 0;
553 }
554 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n",
555 s->mb_x + s->mb_y * s->mb_stride);
556 return -1;
557 }
558
559 117914 h261_decode_mb_skipped(h,
560 117914 h->current_mba - h->mba_diff,
561 117914 h->current_mba - 1);
562 }
563
564 return -1;
565 }
566
567 /**
568 * returns the number of bytes consumed for building the current frame
569 */
570 300 static int get_consumed_bytes(MpegEncContext *s, int buf_size)
571 {
572 300 int pos = get_bits_count(&s->gb) >> 3;
573
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300 if (pos == 0)
574 pos = 1; // avoid infinite loops (i doubt that is needed but ...)
575
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300 if (pos + 10 > buf_size)
576 300 pos = buf_size; // oops ;)
577
578 300 return pos;
579 }
580
581 300 static int h261_decode_frame(AVCodecContext *avctx, void *data,
582 int *got_frame, AVPacket *avpkt)
583 {
584 300 const uint8_t *buf = avpkt->data;
585 300 int buf_size = avpkt->size;
586 300 H261Context *h = avctx->priv_data;
587 300 MpegEncContext *s = &h->s;
588 int ret;
589 300 AVFrame *pict = data;
590
591 ff_dlog(avctx, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
592 ff_dlog(avctx, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
593
594 300 h->gob_start_code_skipped = 0;
595
596 306 retry:
597 306 init_get_bits(&s->gb, buf, buf_size * 8);
598
599 306 ret = h261_decode_picture_header(h);
600
601 /* skip if the header was thrashed */
602
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306 if (ret < 0) {
603 av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
604 return -1;
605 }
606
607
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306 if (s->width != avctx->coded_width || s->height != avctx->coded_height) {
608 ff_mpv_common_end(s);
609 }
610
611
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306 if (!s->context_initialized) {
612
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6 if ((ret = ff_mpv_common_init(s)) < 0)
613 return ret;
614
615 6 ret = ff_set_dimensions(avctx, s->width, s->height);
616
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6 if (ret < 0)
617 return ret;
618
619 6 goto retry;
620 }
621
622 // for skipping the frame
623 300 s->current_picture.f->pict_type = s->pict_type;
624 300 s->current_picture.f->key_frame = s->pict_type == AV_PICTURE_TYPE_I;
625
626
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300 if ((avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type == AV_PICTURE_TYPE_B) ||
627
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300 (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type != AV_PICTURE_TYPE_I) ||
628
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300 avctx->skip_frame >= AVDISCARD_ALL)
629 return get_consumed_bytes(s, buf_size);
630
631
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300 if (ff_mpv_frame_start(s, avctx) < 0)
632 return -1;
633
634 300 ff_mpeg_er_frame_start(s);
635
636 /* decode each macroblock */
637 300 s->mb_x = 0;
638 300 s->mb_y = 0;
639
640
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3900 while (h->gob_number < (s->mb_height == 18 ? 12 : 5)) {
641
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3600 if (h261_resync(h) < 0)
642 break;
643 3600 h261_decode_gob(h);
644 }
645 300 ff_mpv_frame_end(s);
646
647
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300 av_assert0(s->current_picture.f->pict_type == s->current_picture_ptr->f->pict_type);
648
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300 av_assert0(s->current_picture.f->pict_type == s->pict_type);
649
650
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300 if ((ret = av_frame_ref(pict, s->current_picture_ptr->f)) < 0)
651 return ret;
652 300 ff_print_debug_info(s, s->current_picture_ptr, pict);
653
654 300 *got_frame = 1;
655
656 300 return get_consumed_bytes(s, buf_size);
657 }
658
659 13 static av_cold int h261_decode_end(AVCodecContext *avctx)
660 {
661 13 H261Context *h = avctx->priv_data;
662 13 MpegEncContext *s = &h->s;
663
664 13 ff_mpv_common_end(s);
665 13 return 0;
666 }
667
668 const AVCodec ff_h261_decoder = {
669 .name = "h261",
670 .long_name = NULL_IF_CONFIG_SMALL("H.261"),
671 .type = AVMEDIA_TYPE_VIDEO,
672 .id = AV_CODEC_ID_H261,
673 .priv_data_size = sizeof(H261Context),
674 .init = h261_decode_init,
675 .close = h261_decode_end,
676 .decode = h261_decode_frame,
677 .capabilities = AV_CODEC_CAP_DR1,
678 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
679 .max_lowres = 3,
680 };
681