read unsigned Exp-Golomb code

* Convert an AVRational to a `double`. * @param a AVRational to convert * @return `a` in floating-point form * @see av_d2q() */

return the number of undisplayed frames in the queue */

get the current master clock value */

return < 0 if aborted, 0 if no packet and > 0 if packet. */

packet queue handling */

open a given stream. Return 0 if OK */