VkVideoEncodeH264GopRemainingFrameInfoKHR

The VkVideoEncodeH264GopRemainingFrameInfoKHR structure is defined as:

typedef struct VkVideoEncodeH264GopRemainingFrameInfoKHR {
    VkStructureType sType;
    const void* pNext;
    VkBool32 useGopRemainingFrames;
    uint32_t gopRemainingI;
    uint32_t gopRemainingP;
    uint32_t gopRemainingB;
} VkVideoEncodeH264GopRemainingFrameInfoKHR;

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• useGopRemainingFrames indicates whether the implementation’s rate control algorithm should use the values specified in gopRemainingI, gopRemainingP, and gopRemainingB. If useGopRemainingFrames is VK_FALSE, then the values of gopRemainingI, gopRemainingP, and gopRemainingB are ignored.
• gopRemainingI specifies the number of I frames the implementation’s rate control algorithm should assume to be remaining in the GOP prior to executing the video encode operation.
• gopRemainingP specifies the number of P frames the implementation’s rate control algorithm should assume to be remaining in the GOP prior to executing the video encode operation.
• gopRemainingB specifies the number of B frames the implementation’s rate control algorithm should assume to be remaining in the GOP prior to executing the video encode operation.

Setting useGopRemainingFrames to VK_TRUE and including this structure in the pNext chain of VkVideoBeginCodingInfoKHR is only mandatory if the VkVideoEncodeH264CapabilitiesKHR::requiresGopRemainingFrames reported for the used video profile is VK_TRUE. However, implementations may use these remaining frame counts, when specified, even when it is not required. In particular, when the application does not use a regular GOP structure, these values may provide additional guidance for the implementation’s rate control algorithm.

The VkVideoEncodeH264CapabilitiesKHR::prefersGopRemainingFrames capability is also used to indicate that the implementation’s rate control algorithm may operate more accurately if the application specifies the remaining frame counts using this structure.

As with other rate control guidance values, if the effective order and number of frames encoded by the application are not in line with the remaining frame counts specified in this structure at any given point, then the behavior of the implementation’s rate control algorithm may deviate from the one expected by the application.