C Specification
The VkVideoDecodeH264DpbSlotInfoKHR structure is defined as:
// Provided by VK_KHR_video_decode_h264
typedef struct VkVideoDecodeH264DpbSlotInfoKHR {
    VkStructureType                           sType;
    const void*                               pNext;
    const StdVideoDecodeH264ReferenceInfo*    pStdReferenceInfo;
} VkVideoDecodeH264DpbSlotInfoKHR;Members
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sTypeis a VkStructureType value identifying this structure.
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pNextisNULLor a pointer to a structure extending this structure.
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pStdReferenceInfois a pointer to aStdVideoDecodeH264ReferenceInfostructure specifying H.264 reference 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
- 
When this structure is specified in the pNextchain of the elements of VkVideoDecodeInfoKHR::pReferenceSlots, one or two elements are added to the list of active reference pictures used by the video decode operation for each element of VkVideoDecodeInfoKHR::pReferenceSlotsas follows:- 
If neither pStdReferenceInfo->flags.top_field_flagnorpStdReferenceInfo->flags.bottom_field_flagis set, then the picture is added as a frame reference to the list of active reference pictures.
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If pStdReferenceInfo->flags.top_field_flagis set, then the picture is added as a top field reference to the list of active reference pictures.
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If pStdReferenceInfo->flags.bottom_field_flagis set, then the picture is added as a bottom field reference to the list of active reference pictures.
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For each added reference picture, the corresponding image subregion used is determined according to the H.264 Decode Picture Data Access section. 
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Each added reference picture is associated with the DPB slot index specified in the slotIndexmember of the corresponding element of VkVideoDecodeInfoKHR::pReferenceSlots.
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Each added reference picture is associated with the H.264 reference information provided in pStdReferenceInfo.
 
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| 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
 | 
- Reconstructed Picture Information
- 
When this structure is specified in the pNextchain of VkVideoDecodeInfoKHR::pSetupReferenceSlot, the information related to the reconstructed picture is defined as follows:- 
If neither pStdReferenceInfo->flags.top_field_flagnorpStdReferenceInfo->flags.bottom_field_flagis set, then the picture represents a frame.
- 
If pStdReferenceInfo->flags.top_field_flagis set, then the picture represents a field, specifically, the top field of the frame.
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If pStdReferenceInfo->flags.bottom_field_flagis set, then the picture represents a field, specifically, the bottom field of the frame.
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The image subregion used is determined according to the H.264 Decode Picture Data Access section. 
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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.
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The reconstructed picture is associated with the H.264 reference information provided in pStdReferenceInfo.
 
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- Std Reference Information
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The members of the StdVideoDecodeH264ReferenceInfostructure pointed to bypStdReferenceInfoare interpreted as follows:- 
flags.top_field_flagis used to indicate whether the reference is used as top field reference;
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flags.bottom_field_flagis used to indicate whether the reference is used as bottom field reference;
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flags.used_for_long_term_referenceis 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;
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flags.is_non_existingis 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;
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all other members are interpreted as defined in section 8.2 of the ITU-T H.264 Specification. 
 
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Document Notes
For more information, see the Vulkan Specification
This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.