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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "bytestream.h"
20 #include "get_bits.h"
21 #include "golomb.h"
22 #include "h264.h"
23 #include "h264dec.h"
24 #include "h264_parse.h"
25 #include "h264_ps.h"
26 
ff_h264_pred_weight_table(GetBitContext * gb,const SPS * sps,const int * ref_count,int slice_type_nos,H264PredWeightTable * pwt,int picture_structure,void * logctx)27 int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
28                               const int *ref_count, int slice_type_nos,
29                               H264PredWeightTable *pwt,
30                               int picture_structure, void *logctx)
31 {
32     int list, i, j;
33     int luma_def, chroma_def;
34 
35     pwt->use_weight             = 0;
36     pwt->use_weight_chroma      = 0;
37 
38     pwt->luma_log2_weight_denom = get_ue_golomb_31(gb);
39     if (pwt->luma_log2_weight_denom > 7U) {
40         av_log(logctx, AV_LOG_ERROR, "luma_log2_weight_denom %d is out of range\n", pwt->luma_log2_weight_denom);
41         pwt->luma_log2_weight_denom = 0;
42     }
43     luma_def = 1 << pwt->luma_log2_weight_denom;
44 
45     if (sps->chroma_format_idc) {
46         pwt->chroma_log2_weight_denom = get_ue_golomb_31(gb);
47         if (pwt->chroma_log2_weight_denom > 7U) {
48             av_log(logctx, AV_LOG_ERROR, "chroma_log2_weight_denom %d is out of range\n", pwt->chroma_log2_weight_denom);
49             pwt->chroma_log2_weight_denom = 0;
50         }
51         chroma_def = 1 << pwt->chroma_log2_weight_denom;
52     }
53 
54     for (list = 0; list < 2; list++) {
55         pwt->luma_weight_flag[list]   = 0;
56         pwt->chroma_weight_flag[list] = 0;
57         for (i = 0; i < ref_count[list]; i++) {
58             int luma_weight_flag, chroma_weight_flag;
59 
60             luma_weight_flag = get_bits1(gb);
61             if (luma_weight_flag) {
62                 pwt->luma_weight[i][list][0] = get_se_golomb(gb);
63                 pwt->luma_weight[i][list][1] = get_se_golomb(gb);
64                 if ((int8_t)pwt->luma_weight[i][list][0] != pwt->luma_weight[i][list][0] ||
65                     (int8_t)pwt->luma_weight[i][list][1] != pwt->luma_weight[i][list][1])
66                     goto out_range_weight;
67                 if (pwt->luma_weight[i][list][0] != luma_def ||
68                     pwt->luma_weight[i][list][1] != 0) {
69                     pwt->use_weight             = 1;
70                     pwt->luma_weight_flag[list] = 1;
71                 }
72             } else {
73                 pwt->luma_weight[i][list][0] = luma_def;
74                 pwt->luma_weight[i][list][1] = 0;
75             }
76 
77             if (sps->chroma_format_idc) {
78                 chroma_weight_flag = get_bits1(gb);
79                 if (chroma_weight_flag) {
80                     int j;
81                     for (j = 0; j < 2; j++) {
82                         pwt->chroma_weight[i][list][j][0] = get_se_golomb(gb);
83                         pwt->chroma_weight[i][list][j][1] = get_se_golomb(gb);
84                         if ((int8_t)pwt->chroma_weight[i][list][j][0] != pwt->chroma_weight[i][list][j][0] ||
85                             (int8_t)pwt->chroma_weight[i][list][j][1] != pwt->chroma_weight[i][list][j][1]) {
86                             pwt->chroma_weight[i][list][j][0] = chroma_def;
87                             pwt->chroma_weight[i][list][j][1] = 0;
88                             goto out_range_weight;
89                         }
90                         if (pwt->chroma_weight[i][list][j][0] != chroma_def ||
91                             pwt->chroma_weight[i][list][j][1] != 0) {
92                             pwt->use_weight_chroma        = 1;
93                             pwt->chroma_weight_flag[list] = 1;
94                         }
95                     }
96                 } else {
97                     int j;
98                     for (j = 0; j < 2; j++) {
99                         pwt->chroma_weight[i][list][j][0] = chroma_def;
100                         pwt->chroma_weight[i][list][j][1] = 0;
101                     }
102                 }
103             }
104 
105             // for MBAFF
106             if (picture_structure == PICT_FRAME) {
107                 pwt->luma_weight[16 + 2 * i][list][0] = pwt->luma_weight[16 + 2 * i + 1][list][0] = pwt->luma_weight[i][list][0];
108                 pwt->luma_weight[16 + 2 * i][list][1] = pwt->luma_weight[16 + 2 * i + 1][list][1] = pwt->luma_weight[i][list][1];
109                 if (sps->chroma_format_idc) {
110                     for (j = 0; j < 2; j++) {
111                         pwt->chroma_weight[16 + 2 * i][list][j][0] = pwt->chroma_weight[16 + 2 * i + 1][list][j][0] = pwt->chroma_weight[i][list][j][0];
112                         pwt->chroma_weight[16 + 2 * i][list][j][1] = pwt->chroma_weight[16 + 2 * i + 1][list][j][1] = pwt->chroma_weight[i][list][j][1];
113                     }
114                 }
115             }
116         }
117         if (slice_type_nos != AV_PICTURE_TYPE_B)
118             break;
119     }
120     pwt->use_weight = pwt->use_weight || pwt->use_weight_chroma;
121     return 0;
122 out_range_weight:
123     avpriv_request_sample(logctx, "Out of range weight");
124     return AVERROR_INVALIDDATA;
125 }
126 
127 /**
128  * Check if the top & left blocks are available if needed and
129  * change the dc mode so it only uses the available blocks.
130  */
ff_h264_check_intra4x4_pred_mode(int8_t * pred_mode_cache,void * logctx,int top_samples_available,int left_samples_available)131 int ff_h264_check_intra4x4_pred_mode(int8_t *pred_mode_cache, void *logctx,
132                                      int top_samples_available, int left_samples_available)
133 {
134     static const int8_t top[12] = {
135         -1, 0, LEFT_DC_PRED, -1, -1, -1, -1, -1, 0
136     };
137     static const int8_t left[12] = {
138         0, -1, TOP_DC_PRED, 0, -1, -1, -1, 0, -1, DC_128_PRED
139     };
140     int i;
141 
142     if (!(top_samples_available & 0x8000)) {
143         for (i = 0; i < 4; i++) {
144             int status = top[pred_mode_cache[scan8[0] + i]];
145             if (status < 0) {
146                 av_log(logctx, AV_LOG_ERROR,
147                        "top block unavailable for requested intra mode %d\n",
148                        status);
149                 return AVERROR_INVALIDDATA;
150             } else if (status) {
151                 pred_mode_cache[scan8[0] + i] = status;
152             }
153         }
154     }
155 
156     if ((left_samples_available & 0x8888) != 0x8888) {
157         static const int mask[4] = { 0x8000, 0x2000, 0x80, 0x20 };
158         for (i = 0; i < 4; i++)
159             if (!(left_samples_available & mask[i])) {
160                 int status = left[pred_mode_cache[scan8[0] + 8 * i]];
161                 if (status < 0) {
162                     av_log(logctx, AV_LOG_ERROR,
163                            "left block unavailable for requested intra4x4 mode %d\n",
164                            status);
165                     return AVERROR_INVALIDDATA;
166                 } else if (status) {
167                     pred_mode_cache[scan8[0] + 8 * i] = status;
168                 }
169             }
170     }
171 
172     return 0;
173 }
174 
175 /**
176  * Check if the top & left blocks are available if needed and
177  * change the dc mode so it only uses the available blocks.
178  */
ff_h264_check_intra_pred_mode(void * logctx,int top_samples_available,int left_samples_available,int mode,int is_chroma)179 int ff_h264_check_intra_pred_mode(void *logctx, int top_samples_available,
180                                   int left_samples_available,
181                                   int mode, int is_chroma)
182 {
183     static const int8_t top[4]  = { LEFT_DC_PRED8x8, 1, -1, -1 };
184     static const int8_t left[5] = { TOP_DC_PRED8x8, -1,  2, -1, DC_128_PRED8x8 };
185 
186     if (mode > 3U) {
187         av_log(logctx, AV_LOG_ERROR,
188                "out of range intra chroma pred mode\n");
189         return AVERROR_INVALIDDATA;
190     }
191 
192     if (!(top_samples_available & 0x8000)) {
193         mode = top[mode];
194         if (mode < 0) {
195             av_log(logctx, AV_LOG_ERROR,
196                    "top block unavailable for requested intra mode\n");
197             return AVERROR_INVALIDDATA;
198         }
199     }
200 
201     if ((left_samples_available & 0x8080) != 0x8080) {
202         mode = left[mode];
203         if (mode < 0) {
204             av_log(logctx, AV_LOG_ERROR,
205                    "left block unavailable for requested intra mode\n");
206             return AVERROR_INVALIDDATA;
207         }
208         if (is_chroma && (left_samples_available & 0x8080)) {
209             // mad cow disease mode, aka MBAFF + constrained_intra_pred
210             mode = ALZHEIMER_DC_L0T_PRED8x8 +
211                    (!(left_samples_available & 0x8000)) +
212                    2 * (mode == DC_128_PRED8x8);
213         }
214     }
215 
216     return mode;
217 }
218 
ff_h264_parse_ref_count(int * plist_count,int ref_count[2],GetBitContext * gb,const PPS * pps,int slice_type_nos,int picture_structure,void * logctx)219 int ff_h264_parse_ref_count(int *plist_count, int ref_count[2],
220                             GetBitContext *gb, const PPS *pps,
221                             int slice_type_nos, int picture_structure, void *logctx)
222 {
223     int list_count;
224     int num_ref_idx_active_override_flag;
225 
226     // set defaults, might be overridden a few lines later
227     ref_count[0] = pps->ref_count[0];
228     ref_count[1] = pps->ref_count[1];
229 
230     if (slice_type_nos != AV_PICTURE_TYPE_I) {
231         unsigned max[2];
232         max[0] = max[1] = picture_structure == PICT_FRAME ? 15 : 31;
233 
234         num_ref_idx_active_override_flag = get_bits1(gb);
235 
236         if (num_ref_idx_active_override_flag) {
237             ref_count[0] = get_ue_golomb(gb) + 1;
238             if (slice_type_nos == AV_PICTURE_TYPE_B) {
239                 ref_count[1] = get_ue_golomb(gb) + 1;
240             } else
241                 // full range is spec-ok in this case, even for frames
242                 ref_count[1] = 1;
243         }
244 
245         if (slice_type_nos == AV_PICTURE_TYPE_B)
246             list_count = 2;
247         else
248             list_count = 1;
249 
250         if (ref_count[0] - 1 > max[0] || (list_count == 2 && (ref_count[1] - 1 > max[1]))) {
251             av_log(logctx, AV_LOG_ERROR, "reference overflow %u > %u or %u > %u\n",
252                    ref_count[0] - 1, max[0], ref_count[1] - 1, max[1]);
253             ref_count[0] = ref_count[1] = 0;
254             *plist_count = 0;
255             goto fail;
256         } else if (ref_count[1] - 1 > max[1]) {
257             av_log(logctx, AV_LOG_DEBUG, "reference overflow %u > %u \n",
258                    ref_count[1] - 1, max[1]);
259             ref_count[1] = 0;
260         }
261 
262     } else {
263         list_count   = 0;
264         ref_count[0] = ref_count[1] = 0;
265     }
266 
267     *plist_count = list_count;
268 
269     return 0;
270 fail:
271     *plist_count = 0;
272     ref_count[0] = 0;
273     ref_count[1] = 0;
274     return AVERROR_INVALIDDATA;
275 }
276 
ff_h264_init_poc(int pic_field_poc[2],int * pic_poc,const SPS * sps,H264POCContext * pc,int picture_structure,int nal_ref_idc)277 int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
278                      const SPS *sps, H264POCContext *pc,
279                      int picture_structure, int nal_ref_idc)
280 {
281     const int max_frame_num = 1 << sps->log2_max_frame_num;
282     int64_t field_poc[2];
283 
284     pc->frame_num_offset = pc->prev_frame_num_offset;
285     if (pc->frame_num < pc->prev_frame_num)
286         pc->frame_num_offset += max_frame_num;
287 
288     if (sps->poc_type == 0) {
289         const int max_poc_lsb = 1 << sps->log2_max_poc_lsb;
290         if (pc->prev_poc_lsb < 0)
291             pc->prev_poc_lsb =  pc->poc_lsb;
292 
293         if (pc->poc_lsb < pc->prev_poc_lsb &&
294             pc->prev_poc_lsb - pc->poc_lsb >= max_poc_lsb / 2)
295             pc->poc_msb = pc->prev_poc_msb + max_poc_lsb;
296         else if (pc->poc_lsb > pc->prev_poc_lsb &&
297                  pc->prev_poc_lsb - pc->poc_lsb < -max_poc_lsb / 2)
298             pc->poc_msb = pc->prev_poc_msb - max_poc_lsb;
299         else
300             pc->poc_msb = pc->prev_poc_msb;
301         field_poc[0] =
302         field_poc[1] = pc->poc_msb + pc->poc_lsb;
303         if (picture_structure == PICT_FRAME)
304             field_poc[1] += pc->delta_poc_bottom;
305     } else if (sps->poc_type == 1) {
306         int abs_frame_num;
307         int64_t expected_delta_per_poc_cycle, expectedpoc;
308         int i;
309 
310         if (sps->poc_cycle_length != 0)
311             abs_frame_num = pc->frame_num_offset + pc->frame_num;
312         else
313             abs_frame_num = 0;
314 
315         if (nal_ref_idc == 0 && abs_frame_num > 0)
316             abs_frame_num--;
317 
318         expected_delta_per_poc_cycle = 0;
319         for (i = 0; i < sps->poc_cycle_length; i++)
320             // FIXME integrate during sps parse
321             expected_delta_per_poc_cycle += sps->offset_for_ref_frame[i];
322 
323         if (abs_frame_num > 0) {
324             int poc_cycle_cnt          = (abs_frame_num - 1) / sps->poc_cycle_length;
325             int frame_num_in_poc_cycle = (abs_frame_num - 1) % sps->poc_cycle_length;
326 
327             expectedpoc = poc_cycle_cnt * expected_delta_per_poc_cycle;
328             for (i = 0; i <= frame_num_in_poc_cycle; i++)
329                 expectedpoc = expectedpoc + sps->offset_for_ref_frame[i];
330         } else
331             expectedpoc = 0;
332 
333         if (nal_ref_idc == 0)
334             expectedpoc = expectedpoc + sps->offset_for_non_ref_pic;
335 
336         field_poc[0] = expectedpoc + pc->delta_poc[0];
337         field_poc[1] = field_poc[0] + sps->offset_for_top_to_bottom_field;
338 
339         if (picture_structure == PICT_FRAME)
340             field_poc[1] += pc->delta_poc[1];
341     } else {
342         int poc = 2 * (pc->frame_num_offset + pc->frame_num);
343 
344         if (!nal_ref_idc)
345             poc--;
346 
347         field_poc[0] = poc;
348         field_poc[1] = poc;
349     }
350 
351     if (   field_poc[0] != (int)field_poc[0]
352         || field_poc[1] != (int)field_poc[1])
353         return AVERROR_INVALIDDATA;
354 
355     if (picture_structure != PICT_BOTTOM_FIELD)
356         pic_field_poc[0] = field_poc[0];
357     if (picture_structure != PICT_TOP_FIELD)
358         pic_field_poc[1] = field_poc[1];
359     *pic_poc = FFMIN(pic_field_poc[0], pic_field_poc[1]);
360 
361     return 0;
362 }
363 
decode_extradata_ps(const uint8_t * data,int size,H264ParamSets * ps,int is_avc,void * logctx)364 static int decode_extradata_ps(const uint8_t *data, int size, H264ParamSets *ps,
365                                int is_avc, void *logctx)
366 {
367     H2645Packet pkt = { 0 };
368     int i, ret = 0;
369 
370     ret = ff_h2645_packet_split(&pkt, data, size, logctx, is_avc, 2, AV_CODEC_ID_H264, 1, 0);
371     if (ret < 0) {
372         ret = 0;
373         goto fail;
374     }
375 
376     for (i = 0; i < pkt.nb_nals; i++) {
377         H2645NAL *nal = &pkt.nals[i];
378         switch (nal->type) {
379         case H264_NAL_SPS: {
380             GetBitContext tmp_gb = nal->gb;
381             ret = ff_h264_decode_seq_parameter_set(&tmp_gb, logctx, ps, 0);
382             if (ret >= 0)
383                 break;
384             av_log(logctx, AV_LOG_DEBUG,
385                    "SPS decoding failure, trying again with the complete NAL\n");
386             init_get_bits8(&tmp_gb, nal->raw_data + 1, nal->raw_size - 1);
387             ret = ff_h264_decode_seq_parameter_set(&tmp_gb, logctx, ps, 0);
388             if (ret >= 0)
389                 break;
390             ret = ff_h264_decode_seq_parameter_set(&nal->gb, logctx, ps, 1);
391             if (ret < 0)
392                 goto fail;
393             break;
394         }
395         case H264_NAL_PPS:
396             ret = ff_h264_decode_picture_parameter_set(&nal->gb, logctx, ps,
397                                                        nal->size_bits);
398             if (ret < 0)
399                 goto fail;
400             break;
401         default:
402             av_log(logctx, AV_LOG_VERBOSE, "Ignoring NAL type %d in extradata\n",
403                    nal->type);
404             break;
405         }
406     }
407 
408 fail:
409     ff_h2645_packet_uninit(&pkt);
410     return ret;
411 }
412 
413 /* There are (invalid) samples in the wild with mp4-style extradata, where the
414  * parameter sets are stored unescaped (i.e. as RBSP).
415  * This function catches the parameter set decoding failure and tries again
416  * after escaping it */
decode_extradata_ps_mp4(const uint8_t * buf,int buf_size,H264ParamSets * ps,int err_recognition,void * logctx)417 static int decode_extradata_ps_mp4(const uint8_t *buf, int buf_size, H264ParamSets *ps,
418                                    int err_recognition, void *logctx)
419 {
420     int ret;
421 
422     ret = decode_extradata_ps(buf, buf_size, ps, 1, logctx);
423     if (ret < 0 && !(err_recognition & AV_EF_EXPLODE)) {
424         GetByteContext gbc;
425         PutByteContext pbc;
426         uint8_t *escaped_buf;
427         int escaped_buf_size;
428 
429         av_log(logctx, AV_LOG_WARNING,
430                "SPS decoding failure, trying again after escaping the NAL\n");
431 
432         if (buf_size / 2 >= (INT16_MAX - AV_INPUT_BUFFER_PADDING_SIZE) / 3)
433             return AVERROR(ERANGE);
434         escaped_buf_size = buf_size * 3 / 2 + AV_INPUT_BUFFER_PADDING_SIZE;
435         escaped_buf = av_mallocz(escaped_buf_size);
436         if (!escaped_buf)
437             return AVERROR(ENOMEM);
438 
439         bytestream2_init(&gbc, buf, buf_size);
440         bytestream2_init_writer(&pbc, escaped_buf, escaped_buf_size);
441 
442         while (bytestream2_get_bytes_left(&gbc)) {
443             if (bytestream2_get_bytes_left(&gbc) >= 3 &&
444                 bytestream2_peek_be24(&gbc) <= 3) {
445                 bytestream2_put_be24(&pbc, 3);
446                 bytestream2_skip(&gbc, 2);
447             } else
448                 bytestream2_put_byte(&pbc, bytestream2_get_byte(&gbc));
449         }
450 
451         escaped_buf_size = bytestream2_tell_p(&pbc);
452         AV_WB16(escaped_buf, escaped_buf_size - 2);
453 
454         (void)decode_extradata_ps(escaped_buf, escaped_buf_size, ps, 1, logctx);
455         // lorex.mp4 decodes ok even with extradata decoding failing
456         av_freep(&escaped_buf);
457     }
458 
459     return 0;
460 }
461 
ff_h264_decode_extradata(const uint8_t * data,int size,H264ParamSets * ps,int * is_avc,int * nal_length_size,int err_recognition,void * logctx)462 int ff_h264_decode_extradata(const uint8_t *data, int size, H264ParamSets *ps,
463                              int *is_avc, int *nal_length_size,
464                              int err_recognition, void *logctx)
465 {
466     int ret;
467 
468     if (!data || size <= 0)
469         return -1;
470 
471     if (data[0] == 1) {
472         int i, cnt, nalsize;
473         const uint8_t *p = data;
474 
475         *is_avc = 1;
476 
477         if (size < 7) {
478             av_log(logctx, AV_LOG_ERROR, "avcC %d too short\n", size);
479             return AVERROR_INVALIDDATA;
480         }
481 
482         // Decode sps from avcC
483         cnt = *(p + 5) & 0x1f; // Number of sps
484         p  += 6;
485         for (i = 0; i < cnt; i++) {
486             nalsize = AV_RB16(p) + 2;
487             if (nalsize > size - (p - data))
488                 return AVERROR_INVALIDDATA;
489             ret = decode_extradata_ps_mp4(p, nalsize, ps, err_recognition, logctx);
490             if (ret < 0) {
491                 av_log(logctx, AV_LOG_ERROR,
492                        "Decoding sps %d from avcC failed\n", i);
493                 return ret;
494             }
495             p += nalsize;
496         }
497         // Decode pps from avcC
498         cnt = *(p++); // Number of pps
499         for (i = 0; i < cnt; i++) {
500             nalsize = AV_RB16(p) + 2;
501             if (nalsize > size - (p - data))
502                 return AVERROR_INVALIDDATA;
503             ret = decode_extradata_ps_mp4(p, nalsize, ps, err_recognition, logctx);
504             if (ret < 0) {
505                 av_log(logctx, AV_LOG_ERROR,
506                        "Decoding pps %d from avcC failed\n", i);
507                 return ret;
508             }
509             p += nalsize;
510         }
511         // Store right nal length size that will be used to parse all other nals
512         *nal_length_size = (data[4] & 0x03) + 1;
513     } else {
514         *is_avc = 0;
515         ret = decode_extradata_ps(data, size, ps, 0, logctx);
516         if (ret < 0)
517             return ret;
518     }
519     return size;
520 }
521 
522 /**
523  * Compute profile from profile_idc and constraint_set?_flags.
524  *
525  * @param sps SPS
526  *
527  * @return profile as defined by FF_PROFILE_H264_*
528  */
ff_h264_get_profile(const SPS * sps)529 int ff_h264_get_profile(const SPS *sps)
530 {
531     int profile = sps->profile_idc;
532 
533     switch (sps->profile_idc) {
534     case FF_PROFILE_H264_BASELINE:
535         // constraint_set1_flag set to 1
536         profile |= (sps->constraint_set_flags & 1 << 1) ? FF_PROFILE_H264_CONSTRAINED : 0;
537         break;
538     case FF_PROFILE_H264_HIGH_10:
539     case FF_PROFILE_H264_HIGH_422:
540     case FF_PROFILE_H264_HIGH_444_PREDICTIVE:
541         // constraint_set3_flag set to 1
542         profile |= (sps->constraint_set_flags & 1 << 3) ? FF_PROFILE_H264_INTRA : 0;
543         break;
544     }
545 
546     return profile;
547 }
548