[enhance] Adding timeout for vaSyncSurface

[dgurulev]

Current vaSyncSurface interface pushes application to use a separate thread for synchronization, since app. can't afford to block main thread for unknown time.

My suggestion is to a new function add a vaSyncSurface2 w/ timeout parameter -

VAStatus vaSyncSurface2(
    VADisplay dpy,
    VASurfaceID render_target
    unsigned int timeout
);

Either VA_STATUS_ERROR_SURFACE_BUSY\ VA_STATUS_ERROR_HW_BUSY statuses could be re-used to indicate the timeout is expired or a new one status VA_STATUS_ERROR_TIMEOUT could be introduced.

[XinfengZhang]

hi Dmitry, could you help to file a PR about it?

[dgurulev]

@XinfengZhang,

A new question arose during discussion - how we will sync. at 1->N encode scenario? Looks like we need provide a context to the vaSyncSurface2 or introduce a new one dedicated function - vaSyncBuffer to sync on bitstream buffer rather than on input surface.

We need a sync to clarify and discuss options and then I file a PR.