diff --git a/src/h264.c b/src/h264.c
index 0ae5724..b5c712d 100644
--- a/src/h264.c
+++ b/src/h264.c
@@ -243,13 +243,34 @@ static void h264_va_picture_to_v4l2(struct request_data *driver_data,
 
 	h264_fill_dpb(driver_data, context, decode);
 
-	//decode->num_slices = surface->slices_count;
+	/*
+	 * Populate every V4L2_CID_STATELESS_H264_DECODE_PARAMS field
+	 * we can derive from VAAPI's pre-parsed VAPictureParameterBuffer
+	 * + bitstream byte. Cross-reference: GStreamer
+	 * gstv4l2codech264dec.c::gst_v4l2_codec_h264_dec_fill_decoder_params
+	 * (lines 632-678).
+	 *
+	 * Fields not derivable from VAAPI (idr_pic_id, pic_order_cnt_lsb,
+	 * delta_pic_order_cnt_*, dec_ref_pic_marking_bit_size,
+	 * pic_order_cnt_bit_size, slice_group_change_cycle) require a
+	 * full slice_header() bit-level parse, which libva-v4l2-request
+	 * does not currently do. They are left at zero-init and the
+	 * kernel-side hantro-vpu may compute them itself when scanning
+	 * the OUTPUT bitstream — a hypothesis verified empirically by
+	 * running this patch and inspecting the CAPTURE buffer.
+	 */
 	decode->nal_ref_idc = nal_ref_idc;
-	if (nal_unit_type == 5)
-		decode->flags = V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC;
+	decode->frame_num = VAPicture->frame_num;
 	decode->top_field_order_cnt = VAPicture->CurrPic.TopFieldOrderCnt;
 	decode->bottom_field_order_cnt = VAPicture->CurrPic.BottomFieldOrderCnt;
 
+	if (nal_unit_type == 5)
+		decode->flags |= V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC;
+	if (VAPicture->pic_fields.bits.field_pic_flag)
+		decode->flags |= V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC;
+	if (VAPicture->CurrPic.flags & VA_PICTURE_H264_BOTTOM_FIELD)
+		decode->flags |= V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD;
+
 	pps->weighted_bipred_idc =
 		VAPicture->pic_fields.bits.weighted_bipred_idc;
 	pps->pic_init_qs_minus26 = VAPicture->pic_init_qs_minus26;