1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2019 Pengutronix, Michael Tretter <kernel@pengutronix.de> 4 * 5 * Convert NAL units between raw byte sequence payloads (RBSP) and C structs 6 * 7 * The conversion is defined in "ITU-T Rec. H.264 (04/2017) Advanced video 8 * coding for generic audiovisual services". Decoder drivers may use the 9 * parser to parse RBSP from encoded streams and configure the hardware, if 10 * the hardware is not able to parse RBSP itself. Encoder drivers may use the 11 * generator to generate the RBSP for SPS/PPS nal units and add them to the 12 * encoded stream if the hardware does not generate the units. 13 */ 14 15#include <linux/kernel.h> 16#include <linux/types.h> 17#include <linux/string.h> 18#include <linux/v4l2-controls.h> 19 20#include <linux/device.h> 21#include <linux/export.h> 22#include <linux/log2.h> 23 24#include "nal-h264.h" 25#include "nal-rbsp.h" 26 27/* 28 * See Rec. ITU-T H.264 (04/2017) Table 7-1 - NAL unit type codes, syntax 29 * element categories, and NAL unit type classes 30 */ 31enum nal_unit_type { 32 SEQUENCE_PARAMETER_SET = 7, 33 PICTURE_PARAMETER_SET = 8, 34 FILLER_DATA = 12, 35}; 36 37static void nal_h264_write_start_code_prefix(struct rbsp *rbsp) 38{ 39 u8 *p = rbsp->data + DIV_ROUND_UP(rbsp->pos, 8); 40 int i = 4; 41 42 if (DIV_ROUND_UP(rbsp->pos, 8) + i > rbsp->size) { 43 rbsp->error = -EINVAL; 44 return; 45 } 46 47 p[0] = 0x00; 48 p[1] = 0x00; 49 p[2] = 0x00; 50 p[3] = 0x01; 51 52 rbsp->pos += i * 8; 53} 54 55static void nal_h264_read_start_code_prefix(struct rbsp *rbsp) 56{ 57 u8 *p = rbsp->data + DIV_ROUND_UP(rbsp->pos, 8); 58 int i = 4; 59 60 if (DIV_ROUND_UP(rbsp->pos, 8) + i > rbsp->size) { 61 rbsp->error = -EINVAL; 62 return; 63 } 64 65 if (p[0] != 0x00 || p[1] != 0x00 || p[2] != 0x00 || p[3] != 0x01) { 66 rbsp->error = -EINVAL; 67 return; 68 } 69 70 rbsp->pos += i * 8; 71} 72 73static void nal_h264_write_filler_data(struct rbsp *rbsp) 74{ 75 u8 *p = rbsp->data + DIV_ROUND_UP(rbsp->pos, 8); 76 int i; 77 78 /* Keep 1 byte extra for terminating the NAL unit */ 79 i = rbsp->size - DIV_ROUND_UP(rbsp->pos, 8) - 1; 80 memset(p, 0xff, i); 81 rbsp->pos += i * 8; 82} 83 84static void nal_h264_read_filler_data(struct rbsp *rbsp) 85{ 86 u8 *p = rbsp->data + DIV_ROUND_UP(rbsp->pos, 8); 87 88 while (*p == 0xff) { 89 if (DIV_ROUND_UP(rbsp->pos, 8) > rbsp->size) { 90 rbsp->error = -EINVAL; 91 return; 92 } 93 94 p++; 95 rbsp->pos += 8; 96 } 97} 98 99static void nal_h264_rbsp_hrd_parameters(struct rbsp *rbsp, 100 struct nal_h264_hrd_parameters *hrd) 101{ 102 unsigned int i; 103 104 if (!hrd) { 105 rbsp->error = -EINVAL; 106 return; 107 } 108 109 rbsp_uev(rbsp, &hrd->cpb_cnt_minus1); 110 rbsp_bits(rbsp, 4, &hrd->bit_rate_scale); 111 rbsp_bits(rbsp, 4, &hrd->cpb_size_scale); 112 113 for (i = 0; i <= hrd->cpb_cnt_minus1; i++) { 114 rbsp_uev(rbsp, &hrd->bit_rate_value_minus1[i]); 115 rbsp_uev(rbsp, &hrd->cpb_size_value_minus1[i]); 116 rbsp_bit(rbsp, &hrd->cbr_flag[i]); 117 } 118 119 rbsp_bits(rbsp, 5, &hrd->initial_cpb_removal_delay_length_minus1); 120 rbsp_bits(rbsp, 5, &hrd->cpb_removal_delay_length_minus1); 121 rbsp_bits(rbsp, 5, &hrd->dpb_output_delay_length_minus1); 122 rbsp_bits(rbsp, 5, &hrd->time_offset_length); 123} 124 125static void nal_h264_rbsp_vui_parameters(struct rbsp *rbsp, 126 struct nal_h264_vui_parameters *vui) 127{ 128 if (!vui) { 129 rbsp->error = -EINVAL; 130 return; 131 } 132 133 rbsp_bit(rbsp, &vui->aspect_ratio_info_present_flag); 134 if (vui->aspect_ratio_info_present_flag) { 135 rbsp_bits(rbsp, 8, &vui->aspect_ratio_idc); 136 if (vui->aspect_ratio_idc == 255) { 137 rbsp_bits(rbsp, 16, &vui->sar_width); 138 rbsp_bits(rbsp, 16, &vui->sar_height); 139 } 140 } 141 142 rbsp_bit(rbsp, &vui->overscan_info_present_flag); 143 if (vui->overscan_info_present_flag) 144 rbsp_bit(rbsp, &vui->overscan_appropriate_flag); 145 146 rbsp_bit(rbsp, &vui->video_signal_type_present_flag); 147 if (vui->video_signal_type_present_flag) { 148 rbsp_bits(rbsp, 3, &vui->video_format); 149 rbsp_bit(rbsp, &vui->video_full_range_flag); 150 151 rbsp_bit(rbsp, &vui->colour_description_present_flag); 152 if (vui->colour_description_present_flag) { 153 rbsp_bits(rbsp, 8, &vui->colour_primaries); 154 rbsp_bits(rbsp, 8, &vui->transfer_characteristics); 155 rbsp_bits(rbsp, 8, &vui->matrix_coefficients); 156 } 157 } 158 159 rbsp_bit(rbsp, &vui->chroma_loc_info_present_flag); 160 if (vui->chroma_loc_info_present_flag) { 161 rbsp_uev(rbsp, &vui->chroma_sample_loc_type_top_field); 162 rbsp_uev(rbsp, &vui->chroma_sample_loc_type_bottom_field); 163 } 164 165 rbsp_bit(rbsp, &vui->timing_info_present_flag); 166 if (vui->timing_info_present_flag) { 167 rbsp_bits(rbsp, 32, &vui->num_units_in_tick); 168 rbsp_bits(rbsp, 32, &vui->time_scale); 169 rbsp_bit(rbsp, &vui->fixed_frame_rate_flag); 170 } 171 172 rbsp_bit(rbsp, &vui->nal_hrd_parameters_present_flag); 173 if (vui->nal_hrd_parameters_present_flag) 174 nal_h264_rbsp_hrd_parameters(rbsp, &vui->nal_hrd_parameters); 175 176 rbsp_bit(rbsp, &vui->vcl_hrd_parameters_present_flag); 177 if (vui->vcl_hrd_parameters_present_flag) 178 nal_h264_rbsp_hrd_parameters(rbsp, &vui->vcl_hrd_parameters); 179 180 if (vui->nal_hrd_parameters_present_flag || 181 vui->vcl_hrd_parameters_present_flag) 182 rbsp_bit(rbsp, &vui->low_delay_hrd_flag); 183 184 rbsp_bit(rbsp, &vui->pic_struct_present_flag); 185 186 rbsp_bit(rbsp, &vui->bitstream_restriction_flag); 187 if (vui->bitstream_restriction_flag) { 188 rbsp_bit(rbsp, &vui->motion_vectors_over_pic_boundaries_flag); 189 rbsp_uev(rbsp, &vui->max_bytes_per_pic_denom); 190 rbsp_uev(rbsp, &vui->max_bits_per_mb_denom); 191 rbsp_uev(rbsp, &vui->log2_max_mv_length_horizontal); 192 rbsp_uev(rbsp, &vui->log21_max_mv_length_vertical); 193 rbsp_uev(rbsp, &vui->max_num_reorder_frames); 194 rbsp_uev(rbsp, &vui->max_dec_frame_buffering); 195 } 196} 197 198static void nal_h264_rbsp_sps(struct rbsp *rbsp, struct nal_h264_sps *sps) 199{ 200 unsigned int i; 201 202 if (!sps) { 203 rbsp->error = -EINVAL; 204 return; 205 } 206 207 rbsp_bits(rbsp, 8, &sps->profile_idc); 208 rbsp_bit(rbsp, &sps->constraint_set0_flag); 209 rbsp_bit(rbsp, &sps->constraint_set1_flag); 210 rbsp_bit(rbsp, &sps->constraint_set2_flag); 211 rbsp_bit(rbsp, &sps->constraint_set3_flag); 212 rbsp_bit(rbsp, &sps->constraint_set4_flag); 213 rbsp_bit(rbsp, &sps->constraint_set5_flag); 214 rbsp_bits(rbsp, 2, &sps->reserved_zero_2bits); 215 rbsp_bits(rbsp, 8, &sps->level_idc); 216 217 rbsp_uev(rbsp, &sps->seq_parameter_set_id); 218 219 if (sps->profile_idc == 100 || sps->profile_idc == 110 || 220 sps->profile_idc == 122 || sps->profile_idc == 244 || 221 sps->profile_idc == 44 || sps->profile_idc == 83 || 222 sps->profile_idc == 86 || sps->profile_idc == 118 || 223 sps->profile_idc == 128 || sps->profile_idc == 138 || 224 sps->profile_idc == 139 || sps->profile_idc == 134 || 225 sps->profile_idc == 135) { 226 rbsp_uev(rbsp, &sps->chroma_format_idc); 227 228 if (sps->chroma_format_idc == 3) 229 rbsp_bit(rbsp, &sps->separate_colour_plane_flag); 230 rbsp_uev(rbsp, &sps->bit_depth_luma_minus8); 231 rbsp_uev(rbsp, &sps->bit_depth_chroma_minus8); 232 rbsp_bit(rbsp, &sps->qpprime_y_zero_transform_bypass_flag); 233 rbsp_bit(rbsp, &sps->seq_scaling_matrix_present_flag); 234 if (sps->seq_scaling_matrix_present_flag) 235 rbsp->error = -EINVAL; 236 } 237 238 rbsp_uev(rbsp, &sps->log2_max_frame_num_minus4); 239 240 rbsp_uev(rbsp, &sps->pic_order_cnt_type); 241 switch (sps->pic_order_cnt_type) { 242 case 0: 243 rbsp_uev(rbsp, &sps->log2_max_pic_order_cnt_lsb_minus4); 244 break; 245 case 1: 246 rbsp_bit(rbsp, &sps->delta_pic_order_always_zero_flag); 247 rbsp_sev(rbsp, &sps->offset_for_non_ref_pic); 248 rbsp_sev(rbsp, &sps->offset_for_top_to_bottom_field); 249 250 rbsp_uev(rbsp, &sps->num_ref_frames_in_pic_order_cnt_cycle); 251 for (i = 0; i < sps->num_ref_frames_in_pic_order_cnt_cycle; i++) 252 rbsp_sev(rbsp, &sps->offset_for_ref_frame[i]); 253 break; 254 default: 255 rbsp->error = -EINVAL; 256 break; 257 } 258 259 rbsp_uev(rbsp, &sps->max_num_ref_frames); 260 rbsp_bit(rbsp, &sps->gaps_in_frame_num_value_allowed_flag); 261 rbsp_uev(rbsp, &sps->pic_width_in_mbs_minus1); 262 rbsp_uev(rbsp, &sps->pic_height_in_map_units_minus1); 263 264 rbsp_bit(rbsp, &sps->frame_mbs_only_flag); 265 if (!sps->frame_mbs_only_flag) 266 rbsp_bit(rbsp, &sps->mb_adaptive_frame_field_flag); 267 268 rbsp_bit(rbsp, &sps->direct_8x8_inference_flag); 269 270 rbsp_bit(rbsp, &sps->frame_cropping_flag); 271 if (sps->frame_cropping_flag) { 272 rbsp_uev(rbsp, &sps->crop_left); 273 rbsp_uev(rbsp, &sps->crop_right); 274 rbsp_uev(rbsp, &sps->crop_top); 275 rbsp_uev(rbsp, &sps->crop_bottom); 276 } 277 278 rbsp_bit(rbsp, &sps->vui_parameters_present_flag); 279 if (sps->vui_parameters_present_flag) 280 nal_h264_rbsp_vui_parameters(rbsp, &sps->vui); 281} 282 283static void nal_h264_rbsp_pps(struct rbsp *rbsp, struct nal_h264_pps *pps) 284{ 285 int i; 286 287 rbsp_uev(rbsp, &pps->pic_parameter_set_id); 288 rbsp_uev(rbsp, &pps->seq_parameter_set_id); 289 rbsp_bit(rbsp, &pps->entropy_coding_mode_flag); 290 rbsp_bit(rbsp, &pps->bottom_field_pic_order_in_frame_present_flag); 291 rbsp_uev(rbsp, &pps->num_slice_groups_minus1); 292 if (pps->num_slice_groups_minus1 > 0) { 293 rbsp_uev(rbsp, &pps->slice_group_map_type); 294 switch (pps->slice_group_map_type) { 295 case 0: 296 for (i = 0; i < pps->num_slice_groups_minus1; i++) 297 rbsp_uev(rbsp, &pps->run_length_minus1[i]); 298 break; 299 case 2: 300 for (i = 0; i < pps->num_slice_groups_minus1; i++) { 301 rbsp_uev(rbsp, &pps->top_left[i]); 302 rbsp_uev(rbsp, &pps->bottom_right[i]); 303 } 304 break; 305 case 3: case 4: case 5: 306 rbsp_bit(rbsp, &pps->slice_group_change_direction_flag); 307 rbsp_uev(rbsp, &pps->slice_group_change_rate_minus1); 308 break; 309 case 6: 310 rbsp_uev(rbsp, &pps->pic_size_in_map_units_minus1); 311 for (i = 0; i < pps->pic_size_in_map_units_minus1; i++) 312 rbsp_bits(rbsp, 313 order_base_2(pps->num_slice_groups_minus1 + 1), 314 &pps->slice_group_id[i]); 315 break; 316 default: 317 break; 318 } 319 } 320 rbsp_uev(rbsp, &pps->num_ref_idx_l0_default_active_minus1); 321 rbsp_uev(rbsp, &pps->num_ref_idx_l1_default_active_minus1); 322 rbsp_bit(rbsp, &pps->weighted_pred_flag); 323 rbsp_bits(rbsp, 2, &pps->weighted_bipred_idc); 324 rbsp_sev(rbsp, &pps->pic_init_qp_minus26); 325 rbsp_sev(rbsp, &pps->pic_init_qs_minus26); 326 rbsp_sev(rbsp, &pps->chroma_qp_index_offset); 327 rbsp_bit(rbsp, &pps->deblocking_filter_control_present_flag); 328 rbsp_bit(rbsp, &pps->constrained_intra_pred_flag); 329 rbsp_bit(rbsp, &pps->redundant_pic_cnt_present_flag); 330 if (/* more_rbsp_data() */ false) { 331 rbsp_bit(rbsp, &pps->transform_8x8_mode_flag); 332 rbsp_bit(rbsp, &pps->pic_scaling_matrix_present_flag); 333 if (pps->pic_scaling_matrix_present_flag) 334 rbsp->error = -EINVAL; 335 rbsp_sev(rbsp, &pps->second_chroma_qp_index_offset); 336 } 337} 338 339/** 340 * nal_h264_write_sps() - Write SPS NAL unit into RBSP format 341 * @dev: device pointer 342 * @dest: the buffer that is filled with RBSP data 343 * @n: maximum size of @dest in bytes 344 * @sps: &struct nal_h264_sps to convert to RBSP 345 * 346 * Convert @sps to RBSP data and write it into @dest. 347 * 348 * The size of the SPS NAL unit is not known in advance and this function will 349 * fail, if @dest does not hold sufficient space for the SPS NAL unit. 350 * 351 * Return: number of bytes written to @dest or negative error code 352 */ 353ssize_t nal_h264_write_sps(const struct device *dev, 354 void *dest, size_t n, struct nal_h264_sps *sps) 355{ 356 struct rbsp rbsp; 357 unsigned int forbidden_zero_bit = 0; 358 unsigned int nal_ref_idc = 0; 359 unsigned int nal_unit_type = SEQUENCE_PARAMETER_SET; 360 361 if (!dest) 362 return -EINVAL; 363 364 rbsp_init(&rbsp, dest, n, &write); 365 366 nal_h264_write_start_code_prefix(&rbsp); 367 368 rbsp_bit(&rbsp, &forbidden_zero_bit); 369 rbsp_bits(&rbsp, 2, &nal_ref_idc); 370 rbsp_bits(&rbsp, 5, &nal_unit_type); 371 372 nal_h264_rbsp_sps(&rbsp, sps); 373 374 rbsp_trailing_bits(&rbsp); 375 376 if (rbsp.error) 377 return rbsp.error; 378 379 return DIV_ROUND_UP(rbsp.pos, 8); 380} 381EXPORT_SYMBOL_GPL(nal_h264_write_sps); 382 383/** 384 * nal_h264_read_sps() - Read SPS NAL unit from RBSP format 385 * @dev: device pointer 386 * @sps: the &struct nal_h264_sps to fill from the RBSP data 387 * @src: the buffer that contains the RBSP data 388 * @n: size of @src in bytes 389 * 390 * Read RBSP data from @src and use it to fill @sps. 391 * 392 * Return: number of bytes read from @src or negative error code 393 */ 394ssize_t nal_h264_read_sps(const struct device *dev, 395 struct nal_h264_sps *sps, void *src, size_t n) 396{ 397 struct rbsp rbsp; 398 unsigned int forbidden_zero_bit; 399 unsigned int nal_ref_idc; 400 unsigned int nal_unit_type; 401 402 if (!src) 403 return -EINVAL; 404 405 rbsp_init(&rbsp, src, n, &read); 406 407 nal_h264_read_start_code_prefix(&rbsp); 408 409 rbsp_bit(&rbsp, &forbidden_zero_bit); 410 rbsp_bits(&rbsp, 2, &nal_ref_idc); 411 rbsp_bits(&rbsp, 5, &nal_unit_type); 412 413 if (rbsp.error || 414 forbidden_zero_bit != 0 || 415 nal_ref_idc != 0 || 416 nal_unit_type != SEQUENCE_PARAMETER_SET) 417 return -EINVAL; 418 419 nal_h264_rbsp_sps(&rbsp, sps); 420 421 rbsp_trailing_bits(&rbsp); 422 423 if (rbsp.error) 424 return rbsp.error; 425 426 return DIV_ROUND_UP(rbsp.pos, 8); 427} 428EXPORT_SYMBOL_GPL(nal_h264_read_sps); 429 430/** 431 * nal_h264_write_pps() - Write PPS NAL unit into RBSP format 432 * @dev: device pointer 433 * @dest: the buffer that is filled with RBSP data 434 * @n: maximum size of @dest in bytes 435 * @pps: &struct nal_h264_pps to convert to RBSP 436 * 437 * Convert @pps to RBSP data and write it into @dest. 438 * 439 * The size of the PPS NAL unit is not known in advance and this function will 440 * fail, if @dest does not hold sufficient space for the PPS NAL unit. 441 * 442 * Return: number of bytes written to @dest or negative error code 443 */ 444ssize_t nal_h264_write_pps(const struct device *dev, 445 void *dest, size_t n, struct nal_h264_pps *pps) 446{ 447 struct rbsp rbsp; 448 unsigned int forbidden_zero_bit = 0; 449 unsigned int nal_ref_idc = 0; 450 unsigned int nal_unit_type = PICTURE_PARAMETER_SET; 451 452 if (!dest) 453 return -EINVAL; 454 455 rbsp_init(&rbsp, dest, n, &write); 456 457 nal_h264_write_start_code_prefix(&rbsp); 458 459 /* NAL unit header */ 460 rbsp_bit(&rbsp, &forbidden_zero_bit); 461 rbsp_bits(&rbsp, 2, &nal_ref_idc); 462 rbsp_bits(&rbsp, 5, &nal_unit_type); 463 464 nal_h264_rbsp_pps(&rbsp, pps); 465 466 rbsp_trailing_bits(&rbsp); 467 468 if (rbsp.error) 469 return rbsp.error; 470 471 return DIV_ROUND_UP(rbsp.pos, 8); 472} 473EXPORT_SYMBOL_GPL(nal_h264_write_pps); 474 475/** 476 * nal_h264_read_pps() - Read PPS NAL unit from RBSP format 477 * @dev: device pointer 478 * @pps: the &struct nal_h264_pps to fill from the RBSP data 479 * @src: the buffer that contains the RBSP data 480 * @n: size of @src in bytes 481 * 482 * Read RBSP data from @src and use it to fill @pps. 483 * 484 * Return: number of bytes read from @src or negative error code 485 */ 486ssize_t nal_h264_read_pps(const struct device *dev, 487 struct nal_h264_pps *pps, void *src, size_t n) 488{ 489 struct rbsp rbsp; 490 491 if (!src) 492 return -EINVAL; 493 494 rbsp_init(&rbsp, src, n, &read); 495 496 nal_h264_read_start_code_prefix(&rbsp); 497 498 /* NAL unit header */ 499 rbsp.pos += 8; 500 501 nal_h264_rbsp_pps(&rbsp, pps); 502 503 rbsp_trailing_bits(&rbsp); 504 505 if (rbsp.error) 506 return rbsp.error; 507 508 return DIV_ROUND_UP(rbsp.pos, 8); 509} 510EXPORT_SYMBOL_GPL(nal_h264_read_pps); 511 512/** 513 * nal_h264_write_filler() - Write filler data RBSP 514 * @dev: device pointer 515 * @dest: buffer to fill with filler data 516 * @n: size of the buffer to fill with filler data 517 * 518 * Write a filler data RBSP to @dest with a size of @n bytes and return the 519 * number of written filler data bytes. 520 * 521 * Use this function to generate dummy data in an RBSP data stream that can be 522 * safely ignored by h264 decoders. 523 * 524 * The RBSP format of the filler data is specified in Rec. ITU-T H.264 525 * (04/2017) 7.3.2.7 Filler data RBSP syntax. 526 * 527 * Return: number of filler data bytes (including marker) or negative error 528 */ 529ssize_t nal_h264_write_filler(const struct device *dev, void *dest, size_t n) 530{ 531 struct rbsp rbsp; 532 unsigned int forbidden_zero_bit = 0; 533 unsigned int nal_ref_idc = 0; 534 unsigned int nal_unit_type = FILLER_DATA; 535 536 if (!dest) 537 return -EINVAL; 538 539 rbsp_init(&rbsp, dest, n, &write); 540 541 nal_h264_write_start_code_prefix(&rbsp); 542 543 rbsp_bit(&rbsp, &forbidden_zero_bit); 544 rbsp_bits(&rbsp, 2, &nal_ref_idc); 545 rbsp_bits(&rbsp, 5, &nal_unit_type); 546 547 nal_h264_write_filler_data(&rbsp); 548 549 rbsp_trailing_bits(&rbsp); 550 551 return DIV_ROUND_UP(rbsp.pos, 8); 552} 553EXPORT_SYMBOL_GPL(nal_h264_write_filler); 554 555/** 556 * nal_h264_read_filler() - Read filler data RBSP 557 * @dev: device pointer 558 * @src: buffer with RBSP data that is read 559 * @n: maximum size of src that shall be read 560 * 561 * Read a filler data RBSP from @src up to a maximum size of @n bytes and 562 * return the size of the filler data in bytes including the marker. 563 * 564 * This function is used to parse filler data and skip the respective bytes in 565 * the RBSP data. 566 * 567 * The RBSP format of the filler data is specified in Rec. ITU-T H.264 568 * (04/2017) 7.3.2.7 Filler data RBSP syntax. 569 * 570 * Return: number of filler data bytes (including marker) or negative error 571 */ 572ssize_t nal_h264_read_filler(const struct device *dev, void *src, size_t n) 573{ 574 struct rbsp rbsp; 575 unsigned int forbidden_zero_bit; 576 unsigned int nal_ref_idc; 577 unsigned int nal_unit_type; 578 579 if (!src) 580 return -EINVAL; 581 582 rbsp_init(&rbsp, src, n, &read); 583 584 nal_h264_read_start_code_prefix(&rbsp); 585 586 rbsp_bit(&rbsp, &forbidden_zero_bit); 587 rbsp_bits(&rbsp, 2, &nal_ref_idc); 588 rbsp_bits(&rbsp, 5, &nal_unit_type); 589 590 if (rbsp.error) 591 return rbsp.error; 592 if (forbidden_zero_bit != 0 || 593 nal_ref_idc != 0 || 594 nal_unit_type != FILLER_DATA) 595 return -EINVAL; 596 597 nal_h264_read_filler_data(&rbsp); 598 rbsp_trailing_bits(&rbsp); 599 600 if (rbsp.error) 601 return rbsp.error; 602 603 return DIV_ROUND_UP(rbsp.pos, 8); 604} 605EXPORT_SYMBOL_GPL(nal_h264_read_filler); 606