Father-in-law interrupting during child visitation

If there are certain conditions implied while permitting the visitation rights, you may have to follow it, normally there should be any objection to such visits accompanied by close relatives, but they may object to it if they apprehend danger and risk to the child, but that has to be done by the mother of the child and not her father, he is no where concerned with the case, you may retaliate.

Should I call police and show them video of interruption by father-in-law? She wants me to come alone to visit my child but she is always surrounded by her family and relatives.

You are not supposed to take your friends and relatives to meet your child.  If the child is surrounded by maternal side relatives at the time of visistation creating discomfort and subdued hostile atmosphere defeating the very private companionship you expect with your child, you should move appropriate application in the custody court seeking the appropriate directions at the visiting hours, i.e., the child can be attended only its  mother when you spend time with the child. After all, the child should not be a kicking ball between your relatives and friends and her relatives and her friends.

It depends what the Court Order States...

If you have to pick up the child from in-laws / wife's place.. then you should go alone.. after picking up child can spend time with family and frnds..

if there is any interference by in-laws then..

First, try to create evidence.. collect proof...

Second, File Contempt of Court and also make your in-laws party to it.. since they are creating obstructions in court ordered access.

Third, Make an application to court saying that the child be handed over to you in court in the presence of court Counsellor.