Package org.lwjgl.vulkan

Class VkVideoDecodeH264DpbSlotInfoKHR

java.lang.Object
org.lwjgl.system.Pointer.Default
org.lwjgl.system.Struct<VkVideoDecodeH264DpbSlotInfoKHR>
org.lwjgl.vulkan.VkVideoDecodeH264DpbSlotInfoKHR
All Implemented Interfaces:
AutoCloseable, org.lwjgl.system.NativeResource, org.lwjgl.system.Pointer
public class VkVideoDecodeH264DpbSlotInfoKHR extends org.lwjgl.system.Struct<VkVideoDecodeH264DpbSlotInfoKHR> implements org.lwjgl.system.NativeResource
Structure specifies H.264 decode DPB picture information.
Description

This structure is specified in the pNext chain of VkVideoDecodeInfoKHR::pSetupReferenceSlot, if not NULL, and the pNext chain of the elements of VkVideoDecodeInfoKHR::pReferenceSlots to specify the codec-specific reference picture information for an H.264 decode operation.

Active Reference Picture Information
  • If neither pStdReferenceInfo→flags.top_field_flag nor pStdReferenceInfo→flags.bottom_field_flag is set, then the picture is added as a frame reference to the list of active reference pictures.
  • If pStdReferenceInfo→flags.top_field_flag is set, then the picture is added as a top field reference to the list of active reference pictures.
  • If pStdReferenceInfo→flags.bottom_field_flag is set, then the picture is added as a bottom field reference to the list of active reference pictures.
  • For each added reference picture, the corresponding image subregion used is determined according to the H.264 Decode Picture Data Access section.
  • Each added reference picture is associated with the DPB slot index specified in the slotIndex member of the corresponding element of VkVideoDecodeInfoKHR::pReferenceSlots.
  • Each added reference picture is associated with the H.264 reference information provided in pStdReferenceInfo.
Note

When both the top and bottom field of an interlaced frame currently associated with a DPB slot is intended to be used as an active reference picture and both fields are stored in the same image subregion (which is the case when using VIDEO_DECODE_H264_PICTURE_LAYOUT_INTERLACED_INTERLEAVED_LINES_BIT_KHR which stores the two fields at even and odd scanlines of the same image subregion), both references have to be provided through a single VkVideoReferenceSlotInfoKHR structure that has both flags.top_field_flag and flags.bottom_field_flag set in the StdVideoDecodeH264ReferenceInfo structure pointed to by the pStdReferenceInfo member of the VkVideoDecodeH264DpbSlotInfoKHR structure included in the corresponding VkVideoReferenceSlotInfoKHR structure’s pNext chain. However, this approach can only be used when both fields are stored in the same image subregion. If that is not the case (e.g. when using VIDEO_DECODE_H264_PICTURE_LAYOUT_INTERLACED_SEPARATE_PLANES_BIT_KHR which requires separate codedOffset values for the two fields and also allows storing the two fields of a frame in separate image layers or entirely separate images), then a separate VkVideoReferenceSlotInfoKHR structure needs to be provided for referencing the two fields, each only setting one of flags.top_field_flag or flags.bottom_field_flag, and providing the appropriate video picture resource information in VkVideoReferenceSlotInfoKHR::pPictureResource.

Reconstructed Picture Information
  • If neither pStdReferenceInfo→flags.top_field_flag nor pStdReferenceInfo→flags.bottom_field_flag is set, then the picture represents a frame.
  • If pStdReferenceInfo→flags.top_field_flag is set, then the picture represents a field, specifically, the top field of the frame.
  • If pStdReferenceInfo→flags.bottom_field_flag is set, then the picture represents a field, specifically, the bottom field of the frame.
  • The image subregion used is determined according to the H.264 Decode Picture Data Access section.
  • If reference picture setup is requested, then the reconstructed picture is used to activate the DPB slot with the index specified in VkVideoDecodeInfoKHR::pSetupReferenceSlot→slotIndex.
  • The reconstructed picture is associated with the H.264 reference information provided in pStdReferenceInfo.
Std Reference Information
  • flags.top_field_flag is used to indicate whether the reference is used as top field reference;
  • flags.bottom_field_flag is used to indicate whether the reference is used as bottom field reference;
  • flags.used_for_long_term_reference is used to indicate whether the picture is marked as “used for long-term reference” as defined in section 8.2.5.1 of the ITU-T H.264 Specification;
  • flags.is_non_existing is used to indicate whether the picture is marked as “non-existing” as defined in section 8.2.5.2 of the ITU-T H.264 Specification;
  • all other members are interpreted as defined in section 8.2 of the ITU-T H.264 Specification.
Valid Usage (Implicit)

Layout


 struct VkVideoDecodeH264DpbSlotInfoKHR {
     VkStructureType sType();
     void const * pNext();
     StdVideoDecodeH264ReferenceInfo const * pStdReferenceInfo();
 }