Register a user provided lock manager supporting the operations
specified by AVLockOp. mutex points to a (void *) where the
lockmgr should store/get a pointer to a user allocated mutex. It's
NULL upon AV_LOCK_CREATE and != NULL for all other ops.
@param cb User defined callback. Note: FFmpeg may invoke calls to this
callback during the call to av_lockmgr_register().
Thus, the application must be prepared to handle that.
If cb is set to NULL the lockmgr will be unregistered.
Also note that during unregistration the previously registered
lockmgr callback may also be invoked.
Register a user provided lock manager supporting the operations specified by AVLockOp. mutex points to a (void *) where the lockmgr should store/get a pointer to a user allocated mutex. It's NULL upon AV_LOCK_CREATE and != NULL for all other ops.
@param cb User defined callback. Note: FFmpeg may invoke calls to this callback during the call to av_lockmgr_register(). Thus, the application must be prepared to handle that. If cb is set to NULL the lockmgr will be unregistered. Also note that during unregistration the previously registered lockmgr callback may also be invoked.