Videos of police are prevalent in the news of late, whether it be video related to investigations (officer body-camera video of police allegedly planting evidence in Baltimore when investigating a drug case), traffic stops (Philando Castile video), or during apprehensions (Walter Scott video). In the latter two instances, video was taken by private citizens who were observing the police. All of this begs the question, can you legally film police while they are on duty in Texas?
The answer is “yes.” For the most part.
We all have a right to film or take pictures of public events, objects, and people in public that are in plain view (i.e. out in the open). There is nothing, legally speaking, that prevents you from taking photographs of (the exterior of) a federal building in downtown Dallas, for example. Likewise, you can legally record video of, or take photographs of, police who are in public and in plain view. This of course requires that YOU are legally permitted to be where you are—I could not go to a location that I had been criminally trespassed from to record events in public, for example, or otherwise break the law to arrive at the filming location. (On a related note, if you venture onto private property to record or take photographs, the owner of the private property gets to set the rules—the owner could prohibit all photography if he wanted to.)
However, and this a critical point, you cannot interfere with police executing their duties. If you run up to police while they are arresting someone, and interfere with the arrest, then you could be charged with Interfering with a Peace Officer, or other such offenses. Provided you are standing an adequate distance away from the action, and are not yelling at or otherwise interacting with the police or the person they are talking to, it would be very difficult for anyone to argue you are “interfering” in any way.
What if the police see you filming, and demand you give them your phone or delete a video or picture? You are under no obligation to turn over your phone unless they have a warrant. As for deleting a picture or video you took, I am hard pressed to imagine a situation where the police could legally force you to do this.
So, the short answer to whether you can legally film police in public places in Texas is “yes.”