1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _codec-stateless-controls: 4 5********************************* 6Stateless Codec Control Reference 7********************************* 8 9The Stateless Codec control class is intended to support 10stateless decoder and encoders (i.e. hardware accelerators). 11 12These drivers are typically supported by the :ref:`stateless_decoder`, 13and deal with parsed pixel formats such as V4L2_PIX_FMT_H264_SLICE. 14 15Stateless Codec Control ID 16========================== 17 18.. _codec-stateless-control-id: 19 20``V4L2_CID_CODEC_STATELESS_CLASS (class)`` 21 The Stateless Codec class descriptor. 22 23.. _v4l2-codec-stateless-h264: 24 25``V4L2_CID_STATELESS_H264_SPS (struct)`` 26 Specifies the sequence parameter set (as extracted from the 27 bitstream) for the associated H264 slice data. This includes the 28 necessary parameters for configuring a stateless hardware decoding 29 pipeline for H264. The bitstream parameters are defined according 30 to :ref:`h264`, section 7.4.2.1.1 "Sequence Parameter Set Data 31 Semantics". For further documentation, refer to the above 32 specification, unless there is an explicit comment stating 33 otherwise. 34 35.. c:type:: v4l2_ctrl_h264_sps 36 37.. raw:: latex 38 39 \small 40 41.. tabularcolumns:: |p{1.2cm}|p{8.6cm}|p{7.5cm}| 42 43.. flat-table:: struct v4l2_ctrl_h264_sps 44 :header-rows: 0 45 :stub-columns: 0 46 :widths: 1 1 2 47 48 * - __u8 49 - ``profile_idc`` 50 - 51 * - __u8 52 - ``constraint_set_flags`` 53 - See :ref:`Sequence Parameter Set Constraints Set Flags <h264_sps_constraints_set_flags>` 54 * - __u8 55 - ``level_idc`` 56 - 57 * - __u8 58 - ``seq_parameter_set_id`` 59 - 60 * - __u8 61 - ``chroma_format_idc`` 62 - 63 * - __u8 64 - ``bit_depth_luma_minus8`` 65 - 66 * - __u8 67 - ``bit_depth_chroma_minus8`` 68 - 69 * - __u8 70 - ``log2_max_frame_num_minus4`` 71 - 72 * - __u8 73 - ``pic_order_cnt_type`` 74 - 75 * - __u8 76 - ``log2_max_pic_order_cnt_lsb_minus4`` 77 - 78 * - __u8 79 - ``max_num_ref_frames`` 80 - 81 * - __u8 82 - ``num_ref_frames_in_pic_order_cnt_cycle`` 83 - 84 * - __s32 85 - ``offset_for_ref_frame[255]`` 86 - 87 * - __s32 88 - ``offset_for_non_ref_pic`` 89 - 90 * - __s32 91 - ``offset_for_top_to_bottom_field`` 92 - 93 * - __u16 94 - ``pic_width_in_mbs_minus1`` 95 - 96 * - __u16 97 - ``pic_height_in_map_units_minus1`` 98 - 99 * - __u32 100 - ``flags`` 101 - See :ref:`Sequence Parameter Set Flags <h264_sps_flags>` 102 103.. raw:: latex 104 105 \normalsize 106 107.. _h264_sps_constraints_set_flags: 108 109``Sequence Parameter Set Constraints Set Flags`` 110 111.. cssclass:: longtable 112 113.. flat-table:: 114 :header-rows: 0 115 :stub-columns: 0 116 :widths: 1 1 2 117 118 * - ``V4L2_H264_SPS_CONSTRAINT_SET0_FLAG`` 119 - 0x00000001 120 - 121 * - ``V4L2_H264_SPS_CONSTRAINT_SET1_FLAG`` 122 - 0x00000002 123 - 124 * - ``V4L2_H264_SPS_CONSTRAINT_SET2_FLAG`` 125 - 0x00000004 126 - 127 * - ``V4L2_H264_SPS_CONSTRAINT_SET3_FLAG`` 128 - 0x00000008 129 - 130 * - ``V4L2_H264_SPS_CONSTRAINT_SET4_FLAG`` 131 - 0x00000010 132 - 133 * - ``V4L2_H264_SPS_CONSTRAINT_SET5_FLAG`` 134 - 0x00000020 135 - 136 137.. _h264_sps_flags: 138 139``Sequence Parameter Set Flags`` 140 141.. cssclass:: longtable 142 143.. flat-table:: 144 :header-rows: 0 145 :stub-columns: 0 146 :widths: 1 1 2 147 148 * - ``V4L2_H264_SPS_FLAG_SEPARATE_COLOUR_PLANE`` 149 - 0x00000001 150 - 151 * - ``V4L2_H264_SPS_FLAG_QPPRIME_Y_ZERO_TRANSFORM_BYPASS`` 152 - 0x00000002 153 - 154 * - ``V4L2_H264_SPS_FLAG_DELTA_PIC_ORDER_ALWAYS_ZERO`` 155 - 0x00000004 156 - 157 * - ``V4L2_H264_SPS_FLAG_GAPS_IN_FRAME_NUM_VALUE_ALLOWED`` 158 - 0x00000008 159 - 160 * - ``V4L2_H264_SPS_FLAG_FRAME_MBS_ONLY`` 161 - 0x00000010 162 - 163 * - ``V4L2_H264_SPS_FLAG_MB_ADAPTIVE_FRAME_FIELD`` 164 - 0x00000020 165 - 166 * - ``V4L2_H264_SPS_FLAG_DIRECT_8X8_INFERENCE`` 167 - 0x00000040 168 - 169 170``V4L2_CID_STATELESS_H264_PPS (struct)`` 171 Specifies the picture parameter set (as extracted from the 172 bitstream) for the associated H264 slice data. This includes the 173 necessary parameters for configuring a stateless hardware decoding 174 pipeline for H264. The bitstream parameters are defined according 175 to :ref:`h264`, section 7.4.2.2 "Picture Parameter Set RBSP 176 Semantics". For further documentation, refer to the above 177 specification, unless there is an explicit comment stating 178 otherwise. 179 180.. c:type:: v4l2_ctrl_h264_pps 181 182.. raw:: latex 183 184 \small 185 186.. flat-table:: struct v4l2_ctrl_h264_pps 187 :header-rows: 0 188 :stub-columns: 0 189 :widths: 1 1 2 190 191 * - __u8 192 - ``pic_parameter_set_id`` 193 - 194 * - __u8 195 - ``seq_parameter_set_id`` 196 - 197 * - __u8 198 - ``num_slice_groups_minus1`` 199 - 200 * - __u8 201 - ``num_ref_idx_l0_default_active_minus1`` 202 - 203 * - __u8 204 - ``num_ref_idx_l1_default_active_minus1`` 205 - 206 * - __u8 207 - ``weighted_bipred_idc`` 208 - 209 * - __s8 210 - ``pic_init_qp_minus26`` 211 - 212 * - __s8 213 - ``pic_init_qs_minus26`` 214 - 215 * - __s8 216 - ``chroma_qp_index_offset`` 217 - 218 * - __s8 219 - ``second_chroma_qp_index_offset`` 220 - 221 * - __u16 222 - ``flags`` 223 - See :ref:`Picture Parameter Set Flags <h264_pps_flags>` 224 225.. raw:: latex 226 227 \normalsize 228 229.. _h264_pps_flags: 230 231``Picture Parameter Set Flags`` 232 233.. raw:: latex 234 235 \begingroup 236 \scriptsize 237 \setlength{\tabcolsep}{2pt} 238 239.. tabularcolumns:: |p{9.8cm}|p{1.0cm}|p{6.5cm}| 240 241.. flat-table:: 242 :header-rows: 0 243 :stub-columns: 0 244 :widths: 10 1 4 245 246 * - ``V4L2_H264_PPS_FLAG_ENTROPY_CODING_MODE`` 247 - 0x0001 248 - 249 * - ``V4L2_H264_PPS_FLAG_BOTTOM_FIELD_PIC_ORDER_IN_FRAME_PRESENT`` 250 - 0x0002 251 - 252 * - ``V4L2_H264_PPS_FLAG_WEIGHTED_PRED`` 253 - 0x0004 254 - 255 * - ``V4L2_H264_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT`` 256 - 0x0008 257 - 258 * - ``V4L2_H264_PPS_FLAG_CONSTRAINED_INTRA_PRED`` 259 - 0x0010 260 - 261 * - ``V4L2_H264_PPS_FLAG_REDUNDANT_PIC_CNT_PRESENT`` 262 - 0x0020 263 - 264 * - ``V4L2_H264_PPS_FLAG_TRANSFORM_8X8_MODE`` 265 - 0x0040 266 - 267 * - ``V4L2_H264_PPS_FLAG_SCALING_MATRIX_PRESENT`` 268 - 0x0080 269 - ``V4L2_CID_STATELESS_H264_SCALING_MATRIX`` 270 must be used for this picture. 271 272.. raw:: latex 273 274 \endgroup 275 276``V4L2_CID_STATELESS_H264_SCALING_MATRIX (struct)`` 277 Specifies the scaling matrix (as extracted from the bitstream) for 278 the associated H264 slice data. The bitstream parameters are 279 defined according to :ref:`h264`, section 7.4.2.1.1.1 "Scaling 280 List Semantics". For further documentation, refer to the above 281 specification, unless there is an explicit comment stating 282 otherwise. 283 284.. c:type:: v4l2_ctrl_h264_scaling_matrix 285 286.. raw:: latex 287 288 \small 289 290.. tabularcolumns:: |p{0.6cm}|p{4.8cm}|p{11.9cm}| 291 292.. flat-table:: struct v4l2_ctrl_h264_scaling_matrix 293 :header-rows: 0 294 :stub-columns: 0 295 :widths: 1 1 2 296 297 * - __u8 298 - ``scaling_list_4x4[6][16]`` 299 - Scaling matrix after applying the inverse scanning process. 300 Expected list order is Intra Y, Intra Cb, Intra Cr, Inter Y, 301 Inter Cb, Inter Cr. The values on each scaling list are 302 expected in raster scan order. 303 * - __u8 304 - ``scaling_list_8x8[6][64]`` 305 - Scaling matrix after applying the inverse scanning process. 306 Expected list order is Intra Y, Inter Y, Intra Cb, Inter Cb, 307 Intra Cr, Inter Cr. The values on each scaling list are 308 expected in raster scan order. 309 310``V4L2_CID_STATELESS_H264_SLICE_PARAMS (struct)`` 311 Specifies the slice parameters (as extracted from the bitstream) 312 for the associated H264 slice data. This includes the necessary 313 parameters for configuring a stateless hardware decoding pipeline 314 for H264. The bitstream parameters are defined according to 315 :ref:`h264`, section 7.4.3 "Slice Header Semantics". For further 316 documentation, refer to the above specification, unless there is 317 an explicit comment stating otherwise. 318 319.. c:type:: v4l2_ctrl_h264_slice_params 320 321.. raw:: latex 322 323 \small 324 325.. tabularcolumns:: |p{4.0cm}|p{5.9cm}|p{7.4cm}| 326 327.. flat-table:: struct v4l2_ctrl_h264_slice_params 328 :header-rows: 0 329 :stub-columns: 0 330 :widths: 1 1 2 331 332 * - __u32 333 - ``header_bit_size`` 334 - Offset in bits to slice_data() from the beginning of this slice. 335 * - __u32 336 - ``first_mb_in_slice`` 337 - 338 * - __u8 339 - ``slice_type`` 340 - 341 * - __u8 342 - ``colour_plane_id`` 343 - 344 * - __u8 345 - ``redundant_pic_cnt`` 346 - 347 * - __u8 348 - ``cabac_init_idc`` 349 - 350 * - __s8 351 - ``slice_qp_delta`` 352 - 353 * - __s8 354 - ``slice_qs_delta`` 355 - 356 * - __u8 357 - ``disable_deblocking_filter_idc`` 358 - 359 * - __s8 360 - ``slice_alpha_c0_offset_div2`` 361 - 362 * - __s8 363 - ``slice_beta_offset_div2`` 364 - 365 * - __u8 366 - ``num_ref_idx_l0_active_minus1`` 367 - If num_ref_idx_active_override_flag is not set, this field must be 368 set to the value of num_ref_idx_l0_default_active_minus1 369 * - __u8 370 - ``num_ref_idx_l1_active_minus1`` 371 - If num_ref_idx_active_override_flag is not set, this field must be 372 set to the value of num_ref_idx_l1_default_active_minus1 373 * - __u8 374 - ``reserved`` 375 - Applications and drivers must set this to zero. 376 * - struct :c:type:`v4l2_h264_reference` 377 - ``ref_pic_list0[32]`` 378 - Reference picture list after applying the per-slice modifications 379 * - struct :c:type:`v4l2_h264_reference` 380 - ``ref_pic_list1[32]`` 381 - Reference picture list after applying the per-slice modifications 382 * - __u32 383 - ``flags`` 384 - See :ref:`Slice Parameter Flags <h264_slice_flags>` 385 386.. raw:: latex 387 388 \normalsize 389 390.. _h264_slice_flags: 391 392``Slice Parameter Set Flags`` 393 394.. cssclass:: longtable 395 396.. flat-table:: 397 :header-rows: 0 398 :stub-columns: 0 399 :widths: 1 1 2 400 401 * - ``V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED`` 402 - 0x00000001 403 - 404 * - ``V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH`` 405 - 0x00000002 406 - 407 408``V4L2_CID_STATELESS_H264_PRED_WEIGHTS (struct)`` 409 Prediction weight table defined according to :ref:`h264`, 410 section 7.4.3.2 "Prediction Weight Table Semantics". 411 The prediction weight table must be passed by applications 412 under the conditions explained in section 7.3.3 "Slice header 413 syntax". 414 415.. c:type:: v4l2_ctrl_h264_pred_weights 416 417.. raw:: latex 418 419 \small 420 421.. tabularcolumns:: |p{4.9cm}|p{4.9cm}|p{7.5cm}| 422 423.. flat-table:: struct v4l2_ctrl_h264_pred_weights 424 :header-rows: 0 425 :stub-columns: 0 426 :widths: 1 1 2 427 428 * - __u16 429 - ``luma_log2_weight_denom`` 430 - 431 * - __u16 432 - ``chroma_log2_weight_denom`` 433 - 434 * - struct :c:type:`v4l2_h264_weight_factors` 435 - ``weight_factors[2]`` 436 - The weight factors at index 0 are the weight factors for the reference 437 list 0, the one at index 1 for the reference list 1. 438 439.. raw:: latex 440 441 \normalsize 442 443.. c:type:: v4l2_h264_weight_factors 444 445.. raw:: latex 446 447 \small 448 449.. tabularcolumns:: |p{1.0cm}|p{4.5cm}|p{11.8cm}| 450 451.. flat-table:: struct v4l2_h264_weight_factors 452 :header-rows: 0 453 :stub-columns: 0 454 :widths: 1 1 2 455 456 * - __s16 457 - ``luma_weight[32]`` 458 - 459 * - __s16 460 - ``luma_offset[32]`` 461 - 462 * - __s16 463 - ``chroma_weight[32][2]`` 464 - 465 * - __s16 466 - ``chroma_offset[32][2]`` 467 - 468 469.. raw:: latex 470 471 \normalsize 472 473``Picture Reference`` 474 475.. c:type:: v4l2_h264_reference 476 477.. cssclass:: longtable 478 479.. flat-table:: struct v4l2_h264_reference 480 :header-rows: 0 481 :stub-columns: 0 482 :widths: 1 1 2 483 484 * - __u8 485 - ``fields`` 486 - Specifies how the picture is referenced. See :ref:`Reference Fields <h264_ref_fields>` 487 * - __u8 488 - ``index`` 489 - Index into the :c:type:`v4l2_ctrl_h264_decode_params`.dpb array. 490 491.. _h264_ref_fields: 492 493``Reference Fields`` 494 495.. raw:: latex 496 497 \small 498 499.. tabularcolumns:: |p{5.4cm}|p{0.8cm}|p{11.1cm}| 500 501.. flat-table:: 502 :header-rows: 0 503 :stub-columns: 0 504 :widths: 1 1 2 505 506 * - ``V4L2_H264_TOP_FIELD_REF`` 507 - 0x1 508 - The top field in field pair is used for short-term reference. 509 * - ``V4L2_H264_BOTTOM_FIELD_REF`` 510 - 0x2 511 - The bottom field in field pair is used for short-term reference. 512 * - ``V4L2_H264_FRAME_REF`` 513 - 0x3 514 - The frame (or the top/bottom fields, if it's a field pair) 515 is used for short-term reference. 516 517.. raw:: latex 518 519 \normalsize 520 521``V4L2_CID_STATELESS_H264_DECODE_PARAMS (struct)`` 522 Specifies the decode parameters (as extracted from the bitstream) 523 for the associated H264 slice data. This includes the necessary 524 parameters for configuring a stateless hardware decoding pipeline 525 for H264. The bitstream parameters are defined according to 526 :ref:`h264`. For further documentation, refer to the above 527 specification, unless there is an explicit comment stating 528 otherwise. 529 530.. c:type:: v4l2_ctrl_h264_decode_params 531 532.. raw:: latex 533 534 \small 535 536.. tabularcolumns:: |p{4.0cm}|p{5.9cm}|p{7.4cm}| 537 538.. flat-table:: struct v4l2_ctrl_h264_decode_params 539 :header-rows: 0 540 :stub-columns: 0 541 :widths: 1 1 2 542 543 * - struct :c:type:`v4l2_h264_dpb_entry` 544 - ``dpb[16]`` 545 - 546 * - __u16 547 - ``nal_ref_idc`` 548 - NAL reference ID value coming from the NAL Unit header 549 * - __u16 550 - ``frame_num`` 551 - 552 * - __s32 553 - ``top_field_order_cnt`` 554 - Picture Order Count for the coded top field 555 * - __s32 556 - ``bottom_field_order_cnt`` 557 - Picture Order Count for the coded bottom field 558 * - __u16 559 - ``idr_pic_id`` 560 - 561 * - __u16 562 - ``pic_order_cnt_lsb`` 563 - 564 * - __s32 565 - ``delta_pic_order_cnt_bottom`` 566 - 567 * - __s32 568 - ``delta_pic_order_cnt0`` 569 - 570 * - __s32 571 - ``delta_pic_order_cnt1`` 572 - 573 * - __u32 574 - ``dec_ref_pic_marking_bit_size`` 575 - Size in bits of the dec_ref_pic_marking() syntax element. 576 * - __u32 577 - ``pic_order_cnt_bit_size`` 578 - Combined size in bits of the picture order count related syntax 579 elements: pic_order_cnt_lsb, delta_pic_order_cnt_bottom, 580 delta_pic_order_cnt0, and delta_pic_order_cnt1. 581 * - __u32 582 - ``slice_group_change_cycle`` 583 - 584 * - __u32 585 - ``reserved`` 586 - Applications and drivers must set this to zero. 587 * - __u32 588 - ``flags`` 589 - See :ref:`Decode Parameters Flags <h264_decode_params_flags>` 590 591.. raw:: latex 592 593 \normalsize 594 595.. _h264_decode_params_flags: 596 597``Decode Parameters Flags`` 598 599.. raw:: latex 600 601 \small 602 603.. tabularcolumns:: |p{8.3cm}|p{2.1cm}|p{6.9cm}| 604 605.. flat-table:: 606 :header-rows: 0 607 :stub-columns: 0 608 :widths: 1 1 2 609 610 * - ``V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC`` 611 - 0x00000001 612 - That picture is an IDR picture 613 * - ``V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC`` 614 - 0x00000002 615 - 616 * - ``V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD`` 617 - 0x00000004 618 - 619 620.. raw:: latex 621 622 \normalsize 623 624.. c:type:: v4l2_h264_dpb_entry 625 626.. raw:: latex 627 628 \small 629 630.. tabularcolumns:: |p{1.0cm}|p{4.9cm}|p{11.4cm}| 631 632.. flat-table:: struct v4l2_h264_dpb_entry 633 :header-rows: 0 634 :stub-columns: 0 635 :widths: 1 1 2 636 637 * - __u64 638 - ``reference_ts`` 639 - Timestamp of the V4L2 capture buffer to use as reference, used 640 with B-coded and P-coded frames. The timestamp refers to the 641 ``timestamp`` field in struct :c:type:`v4l2_buffer`. Use the 642 :c:func:`v4l2_timeval_to_ns()` function to convert the struct 643 :c:type:`timeval` in struct :c:type:`v4l2_buffer` to a __u64. 644 * - __u32 645 - ``pic_num`` 646 - 647 * - __u16 648 - ``frame_num`` 649 - 650 * - __u8 651 - ``fields`` 652 - Specifies how the DPB entry is referenced. See :ref:`Reference Fields <h264_ref_fields>` 653 * - __u8 654 - ``reserved[5]`` 655 - Applications and drivers must set this to zero. 656 * - __s32 657 - ``top_field_order_cnt`` 658 - 659 * - __s32 660 - ``bottom_field_order_cnt`` 661 - 662 * - __u32 663 - ``flags`` 664 - See :ref:`DPB Entry Flags <h264_dpb_flags>` 665 666.. raw:: latex 667 668 \normalsize 669 670.. _h264_dpb_flags: 671 672``DPB Entries Flags`` 673 674.. raw:: latex 675 676 \small 677 678.. tabularcolumns:: |p{7.7cm}|p{2.1cm}|p{7.5cm}| 679 680.. flat-table:: 681 :header-rows: 0 682 :stub-columns: 0 683 :widths: 1 1 2 684 685 * - ``V4L2_H264_DPB_ENTRY_FLAG_VALID`` 686 - 0x00000001 687 - The DPB entry is valid (non-empty) and should be considered. 688 * - ``V4L2_H264_DPB_ENTRY_FLAG_ACTIVE`` 689 - 0x00000002 690 - The DPB entry is used for reference. 691 * - ``V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM`` 692 - 0x00000004 693 - The DPB entry is used for long-term reference. 694 * - ``V4L2_H264_DPB_ENTRY_FLAG_FIELD`` 695 - 0x00000008 696 - The DPB entry is a single field or a complementary field pair. 697 698.. raw:: latex 699 700 \normalsize 701 702``V4L2_CID_STATELESS_H264_DECODE_MODE (enum)`` 703 Specifies the decoding mode to use. Currently exposes slice-based and 704 frame-based decoding but new modes might be added later on. 705 This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE 706 pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE 707 are required to set this control in order to specify the decoding mode 708 that is expected for the buffer. 709 Drivers may expose a single or multiple decoding modes, depending 710 on what they can support. 711 712.. c:type:: v4l2_stateless_h264_decode_mode 713 714.. raw:: latex 715 716 \scriptsize 717 718.. tabularcolumns:: |p{7.4cm}|p{0.3cm}|p{9.6cm}| 719 720.. flat-table:: 721 :header-rows: 0 722 :stub-columns: 0 723 :widths: 1 1 2 724 725 * - ``V4L2_STATELESS_H264_DECODE_MODE_SLICE_BASED`` 726 - 0 727 - Decoding is done at the slice granularity. 728 The OUTPUT buffer must contain a single slice. 729 When this mode is selected, the ``V4L2_CID_STATELESS_H264_SLICE_PARAMS`` 730 control shall be set. When multiple slices compose a frame, 731 use of ``V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF`` flag 732 is required. 733 * - ``V4L2_STATELESS_H264_DECODE_MODE_FRAME_BASED`` 734 - 1 735 - Decoding is done at the frame granularity, 736 The OUTPUT buffer must contain all slices needed to decode the 737 frame. The OUTPUT buffer must also contain both fields. 738 This mode will be supported by devices that 739 parse the slice(s) header(s) in hardware. When this mode is 740 selected, the ``V4L2_CID_STATELESS_H264_SLICE_PARAMS`` 741 control shall not be set. 742 743.. raw:: latex 744 745 \normalsize 746 747``V4L2_CID_STATELESS_H264_START_CODE (enum)`` 748 Specifies the H264 slice start code expected for each slice. 749 This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE 750 pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE 751 are required to set this control in order to specify the start code 752 that is expected for the buffer. 753 Drivers may expose a single or multiple start codes, depending 754 on what they can support. 755 756.. c:type:: v4l2_stateless_h264_start_code 757 758.. raw:: latex 759 760 \small 761 762.. tabularcolumns:: |p{7.9cm}|p{0.4cm}|p{9.0cm}| 763 764.. flat-table:: 765 :header-rows: 0 766 :stub-columns: 0 767 :widths: 4 1 4 768 769 * - ``V4L2_STATELESS_H264_START_CODE_NONE`` 770 - 0 771 - Selecting this value specifies that H264 slices are passed 772 to the driver without any start code. The bitstream data should be 773 according to :ref:`h264` 7.3.1 NAL unit syntax, hence contains 774 emulation prevention bytes when required. 775 * - ``V4L2_STATELESS_H264_START_CODE_ANNEX_B`` 776 - 1 777 - Selecting this value specifies that H264 slices are expected 778 to be prefixed by Annex B start codes. According to :ref:`h264` 779 valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001. 780 781.. raw:: latex 782 783 \normalsize 784 785.. _codec-stateless-fwht: 786 787``V4L2_CID_STATELESS_FWHT_PARAMS (struct)`` 788 Specifies the FWHT (Fast Walsh Hadamard Transform) parameters (as extracted 789 from the bitstream) for the associated FWHT data. This includes the necessary 790 parameters for configuring a stateless hardware decoding pipeline for FWHT. 791 This codec is specific to the vicodec test driver. 792 793.. c:type:: v4l2_ctrl_fwht_params 794 795.. raw:: latex 796 797 \small 798 799.. tabularcolumns:: |p{1.4cm}|p{3.9cm}|p{12.0cm}| 800 801.. flat-table:: struct v4l2_ctrl_fwht_params 802 :header-rows: 0 803 :stub-columns: 0 804 :widths: 1 1 2 805 806 * - __u64 807 - ``backward_ref_ts`` 808 - Timestamp of the V4L2 capture buffer to use as backward reference, used 809 with P-coded frames. The timestamp refers to the 810 ``timestamp`` field in struct :c:type:`v4l2_buffer`. Use the 811 :c:func:`v4l2_timeval_to_ns()` function to convert the struct 812 :c:type:`timeval` in struct :c:type:`v4l2_buffer` to a __u64. 813 * - __u32 814 - ``version`` 815 - The version of the codec. Set to ``V4L2_FWHT_VERSION``. 816 * - __u32 817 - ``width`` 818 - The width of the frame. 819 * - __u32 820 - ``height`` 821 - The height of the frame. 822 * - __u32 823 - ``flags`` 824 - The flags of the frame, see :ref:`fwht-flags`. 825 * - __u32 826 - ``colorspace`` 827 - The colorspace of the frame, from enum :c:type:`v4l2_colorspace`. 828 * - __u32 829 - ``xfer_func`` 830 - The transfer function, from enum :c:type:`v4l2_xfer_func`. 831 * - __u32 832 - ``ycbcr_enc`` 833 - The Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`. 834 * - __u32 835 - ``quantization`` 836 - The quantization range, from enum :c:type:`v4l2_quantization`. 837 838.. raw:: latex 839 840 \normalsize 841 842.. _fwht-flags: 843 844FWHT Flags 845========== 846 847.. raw:: latex 848 849 \small 850 851.. tabularcolumns:: |p{7.0cm}|p{2.3cm}|p{8.0cm}| 852 853.. flat-table:: 854 :header-rows: 0 855 :stub-columns: 0 856 :widths: 3 1 4 857 858 * - ``V4L2_FWHT_FL_IS_INTERLACED`` 859 - 0x00000001 860 - Set if this is an interlaced format. 861 * - ``V4L2_FWHT_FL_IS_BOTTOM_FIRST`` 862 - 0x00000002 863 - Set if this is a bottom-first (NTSC) interlaced format. 864 * - ``V4L2_FWHT_FL_IS_ALTERNATE`` 865 - 0x00000004 866 - Set if each 'frame' contains just one field. 867 * - ``V4L2_FWHT_FL_IS_BOTTOM_FIELD`` 868 - 0x00000008 869 - If V4L2_FWHT_FL_IS_ALTERNATE was set, then this is set if this 'frame' is the 870 bottom field, else it is the top field. 871 * - ``V4L2_FWHT_FL_LUMA_IS_UNCOMPRESSED`` 872 - 0x00000010 873 - Set if the Y' (luma) plane is uncompressed. 874 * - ``V4L2_FWHT_FL_CB_IS_UNCOMPRESSED`` 875 - 0x00000020 876 - Set if the Cb plane is uncompressed. 877 * - ``V4L2_FWHT_FL_CR_IS_UNCOMPRESSED`` 878 - 0x00000040 879 - Set if the Cr plane is uncompressed. 880 * - ``V4L2_FWHT_FL_CHROMA_FULL_HEIGHT`` 881 - 0x00000080 882 - Set if the chroma plane has the same height as the luma plane, 883 else the chroma plane is half the height of the luma plane. 884 * - ``V4L2_FWHT_FL_CHROMA_FULL_WIDTH`` 885 - 0x00000100 886 - Set if the chroma plane has the same width as the luma plane, 887 else the chroma plane is half the width of the luma plane. 888 * - ``V4L2_FWHT_FL_ALPHA_IS_UNCOMPRESSED`` 889 - 0x00000200 890 - Set if the alpha plane is uncompressed. 891 * - ``V4L2_FWHT_FL_I_FRAME`` 892 - 0x00000400 893 - Set if this is an I-frame. 894 * - ``V4L2_FWHT_FL_COMPONENTS_NUM_MSK`` 895 - 0x00070000 896 - The number of color components minus one. 897 * - ``V4L2_FWHT_FL_PIXENC_MSK`` 898 - 0x00180000 899 - The mask for the pixel encoding. 900 * - ``V4L2_FWHT_FL_PIXENC_YUV`` 901 - 0x00080000 902 - Set if the pixel encoding is YUV. 903 * - ``V4L2_FWHT_FL_PIXENC_RGB`` 904 - 0x00100000 905 - Set if the pixel encoding is RGB. 906 * - ``V4L2_FWHT_FL_PIXENC_HSV`` 907 - 0x00180000 908 - Set if the pixel encoding is HSV. 909 910.. raw:: latex 911 912 \normalsize 913