Function vaMFAddContext 

pub unsafe extern "C" fn vaMFAddContext(
    dpy: VADisplay,
    mf_context: VAMFContextID,
    context: VAContextID,
) -> VAStatus

vaMFAddContext - Provide ability to associate each context used for Multi-Frame submission and common Multi-Frame context. Try to add context to understand if it is supported. Allocation: this call allocates and/or reallocates all memory objects common for all contexts associated with particular Multi-Frame context. All memory required for each context(pixel buffers, internal driver buffers required for processing) allocated during standard vaCreateContext call for each context. Runtime dependency - if current implementation doesn’t allow to run different entry points/profile, first context added will set entry point/profile for whole Multi-Frame context, all other entry points and profiles can be rejected to be added. Return values: VA_STATUS_SUCCESS - operation successful, context was added. VA_STATUS_ERROR_OPERATION_FAILED - something unexpected happened - application have to close current mf_context and associated contexts and start working with new ones. VA_STATUS_ERROR_INVALID_CONTEXT - ContextID is invalid, means: 1 - mf_context is not valid context or 2 - driver can’t suport different VAEntrypoint or VAProfile simultaneosly and current context contradicts with previously added, application can continue with current mf_context and other contexts passed this call, rejected context can continue work in stand-alone mode or other mf_context. VA_STATUS_ERROR_UNSUPPORTED_ENTRYPOINT - particular context being added was created with with unsupported VAEntrypoint. Application can continue with current mf_context and other contexts passed this call, rejected context can continue work in stand-alone mode. VA_STATUS_ERROR_UNSUPPORTED_PROFILE - Current context with Particular VAEntrypoint is supported but VAProfile is not supported. Application can continue with current mf_context and other contexts passed this call, rejected context can continue work in stand-alone mode. dpy: display adapter. context: context being associated with Multi-Frame context. mf_context: - multi-frame context used to associate contexts for multi-frame submission.