ffmpeg-95.0004-Add-V4L2-request-API-h264-hwaccel.patch

From fb59440a268d956bffa40604e4422420453b4605 Mon Sep 17 00:00:00 2001
From: Jernej Skrabec <jernej.skrabec@siol.net>
Date: Sat, 15 Dec 2018 22:32:16 +0100
Subject: [PATCH 04/12] Add V4L2 request API h264 hwaccel

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
---
 configure                      |   3 +
 libavcodec/Makefile            |   1 +
 libavcodec/h264_slice.c        |   4 +
 libavcodec/h264dec.c           |   3 +
 libavcodec/hwaccels.h          |   1 +
 libavcodec/v4l2_request_h264.c | 443 +++++++++++++++++++++++++++++++++
 6 files changed, 455 insertions(+)
 create mode 100644 libavcodec/v4l2_request_h264.c

diff --git a/configure b/configure
index 6088e8d00c..a967ae0afb 100755
--- a/configure
+++ b/configure
@@ -2804,6 +2804,8 @@ h264_dxva2_hwaccel_deps="dxva2"
 h264_dxva2_hwaccel_select="h264_decoder"
 h264_nvdec_hwaccel_deps="nvdec"
 h264_nvdec_hwaccel_select="h264_decoder"
+h264_v4l2request_hwaccel_deps="v4l2_request h264_v4l2_request"
+h264_v4l2request_hwaccel_select="h264_decoder"
 h264_vaapi_hwaccel_deps="vaapi"
 h264_vaapi_hwaccel_select="h264_decoder"
 h264_vdpau_hwaccel_deps="vdpau"
@@ -6243,6 +6245,7 @@ check_cc vp8_v4l2_m2m linux/videodev2.h "int i = V4L2_PIX_FMT_VP8;"
 check_cc vp9_v4l2_m2m linux/videodev2.h "int i = V4L2_PIX_FMT_VP9;"
 
 check_func_headers "linux/media.h linux/videodev2.h" v4l2_timeval_to_ns
+check_cc h264_v4l2_request linux/videodev2.h "int i = V4L2_PIX_FMT_H264_SLICE;"
 check_cc mpeg2_v4l2_request linux/videodev2.h "int i = V4L2_PIX_FMT_MPEG2_SLICE;"
 
 check_header sys/videoio.h
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 9b945e3f64..2bdfaabb5f 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -852,6 +852,7 @@ OBJS-$(CONFIG_H264_D3D11VA_HWACCEL)       += dxva2_h264.o
 OBJS-$(CONFIG_H264_DXVA2_HWACCEL)         += dxva2_h264.o
 OBJS-$(CONFIG_H264_NVDEC_HWACCEL)         += nvdec_h264.o
 OBJS-$(CONFIG_H264_QSV_HWACCEL)           += qsvdec_h2645.o
+OBJS-$(CONFIG_H264_V4L2REQUEST_HWACCEL)   += v4l2_request_h264.o
 OBJS-$(CONFIG_H264_VAAPI_HWACCEL)         += vaapi_h264.o
 OBJS-$(CONFIG_H264_VDPAU_HWACCEL)         += vdpau_h264.o
 OBJS-$(CONFIG_H264_VIDEOTOOLBOX_HWACCEL)  += videotoolbox.o
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index af9ec9789b..f1e11003af 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -758,6 +758,7 @@ static enum AVPixelFormat get_pixel_format(H264Context *h, int force_callback)
 #define HWACCEL_MAX (CONFIG_H264_DXVA2_HWACCEL + \
                      (CONFIG_H264_D3D11VA_HWACCEL * 2) + \
                      CONFIG_H264_NVDEC_HWACCEL + \
+                     CONFIG_H264_V4L2REQUEST_HWACCEL + \
                      CONFIG_H264_VAAPI_HWACCEL + \
                      CONFIG_H264_VIDEOTOOLBOX_HWACCEL + \
                      CONFIG_H264_VDPAU_HWACCEL)
@@ -842,6 +843,9 @@ static enum AVPixelFormat get_pixel_format(H264Context *h, int force_callback)
 #endif
 #if CONFIG_H264_VIDEOTOOLBOX_HWACCEL
             *fmt++ = AV_PIX_FMT_VIDEOTOOLBOX;
+#endif
+#if CONFIG_H264_V4L2REQUEST_HWACCEL
+            *fmt++ = AV_PIX_FMT_DRM_PRIME;
 #endif
             if (h->avctx->codec->pix_fmts)
                 choices = h->avctx->codec->pix_fmts;
diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
index 33e1056d87..3ccfa60621 100644
--- a/libavcodec/h264dec.c
+++ b/libavcodec/h264dec.c
@@ -1078,6 +1078,9 @@ AVCodec ff_h264_decoder = {
 #endif
 #if CONFIG_H264_VIDEOTOOLBOX_HWACCEL
                                HWACCEL_VIDEOTOOLBOX(h264),
+#endif
+#if CONFIG_H264_V4L2REQUEST_HWACCEL
+                               HWACCEL_V4L2REQUEST(h264),
 #endif
                                NULL
                            },
diff --git a/libavcodec/hwaccels.h b/libavcodec/hwaccels.h
index ef54de2a3b..003200edea 100644
--- a/libavcodec/hwaccels.h
+++ b/libavcodec/hwaccels.h
@@ -27,6 +27,7 @@ extern const AVHWAccel ff_h264_d3d11va_hwaccel;
 extern const AVHWAccel ff_h264_d3d11va2_hwaccel;
 extern const AVHWAccel ff_h264_dxva2_hwaccel;
 extern const AVHWAccel ff_h264_nvdec_hwaccel;
+extern const AVHWAccel ff_h264_v4l2request_hwaccel;
 extern const AVHWAccel ff_h264_vaapi_hwaccel;
 extern const AVHWAccel ff_h264_vdpau_hwaccel;
 extern const AVHWAccel ff_h264_videotoolbox_hwaccel;
diff --git a/libavcodec/v4l2_request_h264.c b/libavcodec/v4l2_request_h264.c
new file mode 100644
index 0000000000..81b3c4b092
--- /dev/null
+++ b/libavcodec/v4l2_request_h264.c
@@ -0,0 +1,443 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "h264dec.h"
+#include "hwaccel.h"
+#include "v4l2_request.h"
+
+typedef struct V4L2RequestControlsH264 {
+    struct v4l2_ctrl_h264_sps sps;
+    struct v4l2_ctrl_h264_pps pps;
+    struct v4l2_ctrl_h264_scaling_matrix scaling_matrix;
+    struct v4l2_ctrl_h264_decode_params decode_params;
+    struct v4l2_ctrl_h264_slice_params slice_params[16];
+    int first_slice;
+} V4L2RequestControlsH264;
+
+typedef struct V4L2RequestContextH264 {
+    V4L2RequestContext base;
+    int decode_mode;
+    int start_code;
+} V4L2RequestContextH264;
+
+static uint8_t nalu_slice_start_code[] = { 0x00, 0x00, 0x01 };
+
+static void fill_weight_factors(struct v4l2_h264_weight_factors *factors, int list, const H264SliceContext *sl)
+{
+    for (int i = 0; i < sl->ref_count[list]; i++) {
+        if (sl->pwt.luma_weight_flag[list]) {
+            factors->luma_weight[i] = sl->pwt.luma_weight[i][list][0];
+            factors->luma_offset[i] = sl->pwt.luma_weight[i][list][1];
+        } else {
+            factors->luma_weight[i] = 1 << sl->pwt.luma_log2_weight_denom;
+            factors->luma_offset[i] = 0;
+        }
+        for (int j = 0; j < 2; j++) {
+            if (sl->pwt.chroma_weight_flag[list]) {
+                factors->chroma_weight[i][j] = sl->pwt.chroma_weight[i][list][j][0];
+                factors->chroma_offset[i][j] = sl->pwt.chroma_weight[i][list][j][1];
+            } else {
+                factors->chroma_weight[i][j] = 1 << sl->pwt.chroma_log2_weight_denom;
+                factors->chroma_offset[i][j] = 0;
+            }
+        }
+    }
+}
+
+static void fill_dpb_entry(struct v4l2_h264_dpb_entry *entry, const H264Picture *pic)
+{
+    entry->reference_ts = ff_v4l2_request_get_capture_timestamp(pic->f);
+    entry->frame_num = pic->frame_num;
+    entry->pic_num = pic->pic_id;
+    entry->flags = V4L2_H264_DPB_ENTRY_FLAG_VALID;
+    if (pic->reference)
+        entry->flags |= V4L2_H264_DPB_ENTRY_FLAG_ACTIVE;
+    if (pic->long_ref)
+        entry->flags |= V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM;
+    if (pic->field_poc[0] != INT_MAX)
+        entry->top_field_order_cnt = pic->field_poc[0];
+    if (pic->field_poc[1] != INT_MAX)
+        entry->bottom_field_order_cnt = pic->field_poc[1];
+}
+
+static void fill_dpb(struct v4l2_ctrl_h264_decode_params *decode, const H264Context *h)
+{
+    int entries = 0;
+
+    for (int i = 0; i < h->short_ref_count; i++) {
+        const H264Picture *pic = h->short_ref[i];
+        if (pic && (pic->field_poc[0] != INT_MAX || pic->field_poc[1] != INT_MAX))
+            fill_dpb_entry(&decode->dpb[entries++], pic);
+    }
+
+    if (!h->long_ref_count)
+        return;
+
+    for (int i = 0; i < FF_ARRAY_ELEMS(h->long_ref); i++) {
+        const H264Picture *pic = h->long_ref[i];
+        if (pic && (pic->field_poc[0] != INT_MAX || pic->field_poc[1] != INT_MAX))
+            fill_dpb_entry(&decode->dpb[entries++], pic);
+    }
+}
+
+static uint8_t get_dpb_index(struct v4l2_ctrl_h264_decode_params *decode, const H264Ref *ref)
+{
+    uint64_t timestamp;
+
+    if (!ref->parent)
+        return 0;
+
+    timestamp = ff_v4l2_request_get_capture_timestamp(ref->parent->f);
+
+    for (uint8_t i = 0; i < FF_ARRAY_ELEMS(decode->dpb); i++) {
+        struct v4l2_h264_dpb_entry *entry = &decode->dpb[i];
+        if ((entry->flags & V4L2_H264_DPB_ENTRY_FLAG_VALID) &&
+            entry->reference_ts == timestamp)
+            return i;
+    }
+
+    return 0;
+}
+
+static void fill_sps(struct v4l2_ctrl_h264_sps *ctrl, const H264Context *h)
+{
+    const SPS *sps = h->ps.sps;
+
+    *ctrl = (struct v4l2_ctrl_h264_sps) {
+        .profile_idc = sps->profile_idc,
+        .constraint_set_flags = sps->constraint_set_flags,
+        .level_idc = sps->level_idc,
+        .seq_parameter_set_id = sps->sps_id,
+        .chroma_format_idc = sps->chroma_format_idc,
+        .bit_depth_luma_minus8 = sps->bit_depth_luma - 8,
+        .bit_depth_chroma_minus8 = sps->bit_depth_chroma - 8,
+        .log2_max_frame_num_minus4 = sps->log2_max_frame_num - 4,
+        .pic_order_cnt_type = sps->poc_type,
+        .log2_max_pic_order_cnt_lsb_minus4 = sps->log2_max_poc_lsb - 4,
+        .max_num_ref_frames = sps->ref_frame_count,
+        .num_ref_frames_in_pic_order_cnt_cycle = sps->poc_cycle_length,
+        //.offset_for_ref_frame[255] - not required? not set by libva-v4l2-request - copy sps->offset_for_ref_frame
+        .offset_for_non_ref_pic = sps->offset_for_non_ref_pic,
+        .offset_for_top_to_bottom_field = sps->offset_for_top_to_bottom_field,
+        .pic_width_in_mbs_minus1 = h->mb_width - 1,
+        .pic_height_in_map_units_minus1 = sps->frame_mbs_only_flag ? h->mb_height - 1 : h->mb_height / 2 - 1,
+    };
+
+    if (sps->residual_color_transform_flag)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_SEPARATE_COLOUR_PLANE;
+    if (sps->transform_bypass)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_QPPRIME_Y_ZERO_TRANSFORM_BYPASS;
+    if (sps->delta_pic_order_always_zero_flag)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_DELTA_PIC_ORDER_ALWAYS_ZERO;
+    if (sps->gaps_in_frame_num_allowed_flag)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_GAPS_IN_FRAME_NUM_VALUE_ALLOWED;
+    if (sps->frame_mbs_only_flag)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_FRAME_MBS_ONLY;
+    if (sps->mb_aff)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_MB_ADAPTIVE_FRAME_FIELD;
+    if (sps->direct_8x8_inference_flag)
+        ctrl->flags |= V4L2_H264_SPS_FLAG_DIRECT_8X8_INFERENCE;
+}
+
+static void fill_pps(struct v4l2_ctrl_h264_pps *ctrl, const H264Context *h)
+{
+    const PPS *pps = h->ps.pps;
+    const H264SliceContext *sl = &h->slice_ctx[0];
+
+    *ctrl = (struct v4l2_ctrl_h264_pps) {
+        .pic_parameter_set_id = sl->pps_id,
+        .seq_parameter_set_id = pps->sps_id,
+        .num_slice_groups_minus1 = pps->slice_group_count - 1,
+        .num_ref_idx_l0_default_active_minus1 = pps->ref_count[0] - 1,
+        .num_ref_idx_l1_default_active_minus1 = pps->ref_count[1] - 1,
+        .weighted_bipred_idc = pps->weighted_bipred_idc,
+        .pic_init_qp_minus26 = pps->init_qp - 26,
+        .pic_init_qs_minus26 = pps->init_qs - 26,
+        .chroma_qp_index_offset = pps->chroma_qp_index_offset[0],
+        .second_chroma_qp_index_offset = pps->chroma_qp_index_offset[1],
+    };
+
+    if (pps->cabac)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_ENTROPY_CODING_MODE;
+    if (pps->pic_order_present)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_BOTTOM_FIELD_PIC_ORDER_IN_FRAME_PRESENT;
+    if (pps->weighted_pred)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_WEIGHTED_PRED;
+    if (pps->deblocking_filter_parameters_present)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT;
+    if (pps->constrained_intra_pred)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_CONSTRAINED_INTRA_PRED;
+    if (pps->redundant_pic_cnt_present)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_REDUNDANT_PIC_CNT_PRESENT;
+    if (pps->transform_8x8_mode)
+        ctrl->flags |= V4L2_H264_PPS_FLAG_TRANSFORM_8X8_MODE;
+}
+
+static int v4l2_request_h264_start_frame(AVCodecContext *avctx,
+                                         av_unused const uint8_t *buffer,
+                                         av_unused uint32_t size)
+{
+    const H264Context *h = avctx->priv_data;
+    const PPS *pps = h->ps.pps;
+    const SPS *sps = h->ps.sps;
+    V4L2RequestControlsH264 *controls = h->cur_pic_ptr->hwaccel_picture_private;
+
+    fill_sps(&controls->sps, h);
+    fill_pps(&controls->pps, h);
+
+    memcpy(controls->scaling_matrix.scaling_list_4x4, pps->scaling_matrix4, sizeof(controls->scaling_matrix.scaling_list_4x4));
+    memcpy(controls->scaling_matrix.scaling_list_8x8[0], pps->scaling_matrix8[0], sizeof(controls->scaling_matrix.scaling_list_8x8[0]));
+    memcpy(controls->scaling_matrix.scaling_list_8x8[1], pps->scaling_matrix8[3], sizeof(controls->scaling_matrix.scaling_list_8x8[1]));
+
+    if (sps->chroma_format_idc == 3) {
+        memcpy(controls->scaling_matrix.scaling_list_8x8[2], pps->scaling_matrix8[1], sizeof(controls->scaling_matrix.scaling_list_8x8[2]));
+        memcpy(controls->scaling_matrix.scaling_list_8x8[3], pps->scaling_matrix8[4], sizeof(controls->scaling_matrix.scaling_list_8x8[3]));
+        memcpy(controls->scaling_matrix.scaling_list_8x8[4], pps->scaling_matrix8[2], sizeof(controls->scaling_matrix.scaling_list_8x8[4]));
+        memcpy(controls->scaling_matrix.scaling_list_8x8[5], pps->scaling_matrix8[5], sizeof(controls->scaling_matrix.scaling_list_8x8[5]));
+    }
+
+    controls->decode_params = (struct v4l2_ctrl_h264_decode_params) {
+        .num_slices = 0,
+        .nal_ref_idc = h->nal_ref_idc,
+        .top_field_order_cnt = h->cur_pic_ptr->field_poc[0] != INT_MAX ? h->cur_pic_ptr->field_poc[0] : 0,
+        .bottom_field_order_cnt = h->cur_pic_ptr->field_poc[1] != INT_MAX ? h->cur_pic_ptr->field_poc[1] : 0,
+    };
+
+    if (h->picture_idr)
+        controls->decode_params.flags |= V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC;
+
+    fill_dpb(&controls->decode_params, h);
+
+    controls->first_slice = !FIELD_PICTURE(h) || h->first_field;
+
+    return ff_v4l2_request_reset_frame(avctx, h->cur_pic_ptr->f);
+}
+
+static int v4l2_request_h264_queue_decode(AVCodecContext *avctx, int last_slice)
+{
+    const H264Context *h = avctx->priv_data;
+    V4L2RequestControlsH264 *controls = h->cur_pic_ptr->hwaccel_picture_private;
+    V4L2RequestContextH264 *ctx = avctx->internal->hwaccel_priv_data;
+
+    struct v4l2_ext_control control[] = {
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_SPS,
+            .ptr = &controls->sps,
+            .size = sizeof(controls->sps),
+        },
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_PPS,
+            .ptr = &controls->pps,
+            .size = sizeof(controls->pps),
+        },
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX,
+            .ptr = &controls->scaling_matrix,
+            .size = sizeof(controls->scaling_matrix),
+        },
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS,
+            .ptr = &controls->slice_params,
+            .size = sizeof(controls->slice_params[0]) * FFMIN(controls->decode_params.num_slices, 16),
+        },
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS,
+            .ptr = &controls->decode_params,
+            .size = sizeof(controls->decode_params),
+        },
+    };
+
+    if (ctx->decode_mode == V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED)
+        return ff_v4l2_request_decode_slice(avctx, h->cur_pic_ptr->f, control, FF_ARRAY_ELEMS(control), controls->first_slice, last_slice);
+
+    return ff_v4l2_request_decode_frame(avctx, h->cur_pic_ptr->f, control, FF_ARRAY_ELEMS(control));
+}
+
+static int v4l2_request_h264_decode_slice(AVCodecContext *avctx, const uint8_t *buffer, uint32_t size)
+{
+    const H264Context *h = avctx->priv_data;
+    const PPS *pps = h->ps.pps;
+    const H264SliceContext *sl = &h->slice_ctx[0];
+    V4L2RequestControlsH264 *controls = h->cur_pic_ptr->hwaccel_picture_private;
+    V4L2RequestContextH264 *ctx = avctx->internal->hwaccel_priv_data;
+    V4L2RequestDescriptor *req = (V4L2RequestDescriptor*)h->cur_pic_ptr->f->data[0];
+    int i, ret, count, slice = FFMIN(controls->decode_params.num_slices, 15);
+
+    if (ctx->decode_mode == V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED && slice) {
+        ret = v4l2_request_h264_queue_decode(avctx, 0);
+        if (ret)
+            return ret;
+
+        ff_v4l2_request_reset_frame(avctx, h->cur_pic_ptr->f);
+        slice = controls->decode_params.num_slices = 0;
+        controls->first_slice = 0;
+    }
+
+    controls->slice_params[slice] = (struct v4l2_ctrl_h264_slice_params) {
+        /* Size in bytes, including header */
+        .size = 0,
+        .start_byte_offset = req->output.used,
+        /* Offset in bits to slice_data() from the beginning of this slice. */
+        .header_bit_size = get_bits_count(&sl->gb),
+
+        .first_mb_in_slice = sl->first_mb_addr,
+        .slice_type = ff_h264_get_slice_type(sl),
+        .pic_parameter_set_id = sl->pps_id,
+        .colour_plane_id = 0, /* what is this? */
+        .frame_num = h->poc.frame_num,
+        .idr_pic_id = 0, /* what is this? */
+        .pic_order_cnt_lsb = sl->poc_lsb,
+        .delta_pic_order_cnt_bottom = sl->delta_poc_bottom,
+        .delta_pic_order_cnt0 = sl->delta_poc[0],
+        .delta_pic_order_cnt1 = sl->delta_poc[1],
+        .redundant_pic_cnt = sl->redundant_pic_count,
+
+        /* Size in bits of dec_ref_pic_marking() syntax element. */
+        .dec_ref_pic_marking_bit_size = 0,
+        /* Size in bits of pic order count syntax. */
+        .pic_order_cnt_bit_size = 0,
+
+        .cabac_init_idc = sl->cabac_init_idc,
+        .slice_qp_delta = sl->qscale - pps->init_qp,
+        .slice_qs_delta = 0, /* XXX not implemented by FFmpeg */
+        .disable_deblocking_filter_idc = sl->deblocking_filter < 2 ? !sl->deblocking_filter : sl->deblocking_filter,
+        .slice_alpha_c0_offset_div2 = sl->slice_alpha_c0_offset / 2,
+        .slice_beta_offset_div2 = sl->slice_beta_offset / 2,
+        .slice_group_change_cycle = 0, /* what is this? */
+
+        .num_ref_idx_l0_active_minus1 = sl->list_count > 0 ? sl->ref_count[0] - 1 : 0,
+        .num_ref_idx_l1_active_minus1 = sl->list_count > 1 ? sl->ref_count[1] - 1 : 0,
+    };
+
+    if (FIELD_PICTURE(h))
+        controls->slice_params[slice].flags |= V4L2_H264_SLICE_FLAG_FIELD_PIC;
+    if (h->picture_structure == PICT_BOTTOM_FIELD)
+        controls->slice_params[slice].flags |= V4L2_H264_SLICE_FLAG_BOTTOM_FIELD;
+    if (sl->slice_type == AV_PICTURE_TYPE_B && sl->direct_spatial_mv_pred)
+        controls->slice_params[slice].flags |= V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED;
+
+    controls->slice_params[slice].pred_weight_table.chroma_log2_weight_denom = sl->pwt.chroma_log2_weight_denom;
+    controls->slice_params[slice].pred_weight_table.luma_log2_weight_denom = sl->pwt.luma_log2_weight_denom;
+
+    count = sl->list_count > 0 ? sl->ref_count[0] : 0;
+    for (i = 0; i < count; i++)
+        controls->slice_params[slice].ref_pic_list0[i] = get_dpb_index(&controls->decode_params, &sl->ref_list[0][i]);
+    if (count)
+        fill_weight_factors(&controls->slice_params[slice].pred_weight_table.weight_factors[0], 0, sl);
+
+    count = sl->list_count > 1 ? sl->ref_count[1] : 0;
+    for (i = 0; i < count; i++)
+        controls->slice_params[slice].ref_pic_list1[i] = get_dpb_index(&controls->decode_params, &sl->ref_list[1][i]);
+    if (count)
+        fill_weight_factors(&controls->slice_params[slice].pred_weight_table.weight_factors[1], 1, sl);
+
+    if (ctx->start_code == V4L2_MPEG_VIDEO_H264_START_CODE_ANNEX_B) {
+        ret = ff_v4l2_request_append_output_buffer(avctx, h->cur_pic_ptr->f, nalu_slice_start_code, 3);
+        if (ret)
+            return ret;
+    }
+
+    ret = ff_v4l2_request_append_output_buffer(avctx, h->cur_pic_ptr->f, buffer, size);
+    if (ret)
+        return ret;
+
+    controls->slice_params[slice].size = req->output.used - controls->slice_params[slice].start_byte_offset;
+    controls->decode_params.num_slices++;
+    return 0;
+}
+
+static int v4l2_request_h264_end_frame(AVCodecContext *avctx)
+{
+    const H264Context *h = avctx->priv_data;
+    return v4l2_request_h264_queue_decode(avctx, !FIELD_PICTURE(h) || !h->first_field);
+}
+
+static int v4l2_request_h264_set_controls(AVCodecContext *avctx)
+{
+    V4L2RequestContextH264 *ctx = avctx->internal->hwaccel_priv_data;
+
+    struct v4l2_ext_control control[] = {
+        { .id = V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE, },
+        { .id = V4L2_CID_MPEG_VIDEO_H264_START_CODE, },
+    };
+
+    ctx->decode_mode = ff_v4l2_request_query_control_default_value(avctx, V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE);
+    if (ctx->decode_mode != V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED &&
+        ctx->decode_mode != V4L2_MPEG_VIDEO_H264_DECODE_MODE_FRAME_BASED) {
+        av_log(avctx, AV_LOG_ERROR, "%s: unsupported decode mode, %d\n", __func__, ctx->decode_mode);
+        return AVERROR(EINVAL);
+    }
+
+    ctx->start_code = ff_v4l2_request_query_control_default_value(avctx, V4L2_CID_MPEG_VIDEO_H264_START_CODE);
+    if (ctx->start_code != V4L2_MPEG_VIDEO_H264_START_CODE_NONE &&
+        ctx->start_code != V4L2_MPEG_VIDEO_H264_START_CODE_ANNEX_B) {
+        av_log(avctx, AV_LOG_ERROR, "%s: unsupported start code, %d\n", __func__, ctx->start_code);
+        return AVERROR(EINVAL);
+    }
+
+    control[0].value = ctx->decode_mode;
+    control[1].value = ctx->start_code;
+
+    return ff_v4l2_request_set_controls(avctx, control, FF_ARRAY_ELEMS(control));
+}
+
+static int v4l2_request_h264_init(AVCodecContext *avctx)
+{
+    const H264Context *h = avctx->priv_data;
+    struct v4l2_ctrl_h264_sps sps;
+    struct v4l2_ctrl_h264_pps pps;
+    int ret;
+
+    struct v4l2_ext_control control[] = {
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_SPS,
+            .ptr = &sps,
+            .size = sizeof(sps),
+        },
+        {
+            .id = V4L2_CID_MPEG_VIDEO_H264_PPS,
+            .ptr = &pps,
+            .size = sizeof(pps),
+        },
+    };
+
+    fill_sps(&sps, h);
+    fill_pps(&pps, h);
+
+    ret = ff_v4l2_request_init(avctx, V4L2_PIX_FMT_H264_SLICE, 2 * 1024 * 1024, control, FF_ARRAY_ELEMS(control));
+    if (ret)
+        return ret;
+
+    return v4l2_request_h264_set_controls(avctx);
+}
+
+const AVHWAccel ff_h264_v4l2request_hwaccel = {
+    .name           = "h264_v4l2request",
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_H264,
+    .pix_fmt        = AV_PIX_FMT_DRM_PRIME,
+    .start_frame    = v4l2_request_h264_start_frame,
+    .decode_slice   = v4l2_request_h264_decode_slice,
+    .end_frame      = v4l2_request_h264_end_frame,
+    .frame_priv_data_size = sizeof(V4L2RequestControlsH264),
+    .init           = v4l2_request_h264_init,
+    .uninit         = ff_v4l2_request_uninit,
+    .priv_data_size = sizeof(V4L2RequestContextH264),
+    .frame_params   = ff_v4l2_request_frame_params,
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
+};
-- 
2.24.0