hasvk: Add a slice header parser for H.264 decode.

This is required for long mode, where the driver parses the slice header
itself rather than relying on the hardware to do it.

Co-authored-by: irql-notlessorequal <[email protected]>

[dancingmirrors: Assisted-by: Claude]

src/intel/vulkan_hasvk/anv_video_h264_slice.h

@@ -0,0 +1,99 @@
+/*
+ * Copyright © 2026 [email protected]
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef ANV_VIDEO_H264_SLICE_H
+#define ANV_VIDEO_H264_SLICE_H
+
+#include "vulkan/vulkan.h"
+#include "vulkan/util/vk_util.h"
+
+#include "vk_video/vulkan_video_codec_h264std.h"
+#include "vk_video/vulkan_video_codec_h264std_decode.h"
+
+#define ANV_H264_MAX_REF_FRAMES 16
+#define ANV_H264_SLICE_P 0
+#define ANV_H264_SLICE_B 1
+#define ANV_H264_SLICE_I 2
+#define ANV_H264_SLICE_SP 3
+#define ANV_H264_SLICE_SI 4
+#define ANV_H264_INVALID_SLOT 0xFF
+
+struct anv_h264_slice_params {
+   int first_mb_in_slice;
+   int slice_type;
+   int num_ref_idx_l0_active_minus1;
+   int num_ref_idx_l1_active_minus1;
+   int direct_spatial_mv_pred_flag;
+   int cabac_init_idc;
+   int slice_qp_delta;
+   int disable_deblocking_filter_idc;
+   int slice_alpha_c0_offset_div2;
+   int slice_beta_offset_div2;
+   int luma_log2_weight_denom;
+   int chroma_log2_weight_denom;
+
+   uint8_t ref_list0[ANV_H264_MAX_REF_FRAMES];
+   uint8_t ref_list1[ANV_H264_MAX_REF_FRAMES];
+
+   bool has_weight_offsets_l0;
+   bool has_weight_offsets_l1;
+
+   int16_t luma_weight_l0[ANV_H264_MAX_REF_FRAMES];
+   int16_t luma_offset_l0[ANV_H264_MAX_REF_FRAMES];
+   int16_t chroma_weight_l0[ANV_H264_MAX_REF_FRAMES][2];
+   int16_t chroma_offset_l0[ANV_H264_MAX_REF_FRAMES][2];
+
+   int16_t luma_weight_l1[ANV_H264_MAX_REF_FRAMES];
+   int16_t luma_offset_l1[ANV_H264_MAX_REF_FRAMES];
+   int16_t chroma_weight_l1[ANV_H264_MAX_REF_FRAMES][2];
+   int16_t chroma_offset_l1[ANV_H264_MAX_REF_FRAMES][2];
+
+   uint32_t first_mb_byte_offset;
+   uint32_t first_mb_bit_offset;
+
+   bool parse_ok;
+};
+
+struct anv_h264_rbsp {
+   const uint8_t *buf;
+   const uint8_t *cur;
+   const uint8_t *end;
+   int bit;
+   int zeros;
+   bool error;
+   int bits_consumed;
+};
+
+bool
+anv_h264_parse_slice_header(
+   const uint8_t *buf,
+   uint32_t slice_nalu_offset,
+   uint32_t slice_nalu_size,
+   const StdVideoH264SequenceParameterSet *sps,
+   const StdVideoH264PictureParameterSet *pps,
+   const VkVideoDecodeH264PictureInfoKHR *pic_info,
+   uint32_t ref_slot_count,
+   const VkVideoReferenceSlotInfoKHR *ref_slots,
+   struct anv_h264_slice_params *out);
+
+#endif /* ANV_VIDEO_H264_SLICE_H */