The Problem
Have you ever gone on a road trip with a carload of kids? How about a carload of tech-kids that all have their own iPods, iPhones, iPads, or similar hand-held devices? Trips like these are what made car entertainment systems a smash hit in many vehicles these days. Fact of the matter is, parents want to help kids pass the time and frankly, stay out of their hair while trying to navigate uncharted territory.

We have one of the in-car stock entertainment systems in our van. These are great if you have kids of all the same age range and tastes. When you have three or four kids with significant gaps in age it becomes impossible to get them to agree on an age appropriate movie that everyone can watch.

The Solution
For this problem I have configured the ultimate mobile entertainment system. This simple setup allows each person in the vehicle to watch movies independently on their own device, all streaming “live” from a centralized laptop.

The benefits of this solution are:

You don't need to spend countless hours converting videos to a specific format that will work on iOS devices
You are not relying on the limited storage available on your iOS devices (admit it, most of your storage is being used up by apps anyway!)
Everyone can pick their own movie to watch. They can even watch the same movie but with the ability to pause, rewind and play the movie independently of each other.
Storage is very cheap these days. For around $90 you can get a 1TB drive such as this one! With this you can load up an entire library of videos for everyone to choose from!
The same solution could be used at home, in hotels, etc.

This works amazingly well! The kids won't be able to tell the movies are not local on their own device.

Interested? Read on...

Step 1: Requirements

The minimum requirements for this setup are as follows:

A WiFi Router. I use an old Linksys WRT54G, but almost anything should work. Depending on the router you choose to use, you may also need a RG45 cable to connect directly to it for configuration.
Air Video Server (Windows or Mac). Available for free from http://www.inmethod.com/
Air Video Client (iOS App). Available in the iTunes app store (trial and paid versions)
A Laptop (PC or Mac) to host the movies and act as the streaming server. It doesn't need to be a powerhouse, but it should have at least an Intel Core 2 duo or equivalent CPU. For this Instructable I used a lower end MacBook Pro but I have also used Windows based laptops to do this in the past.
Movies or videos in electronic form (AVI, MP4, WMV, etc.)
- Movies can be either stored on master system hard drive or external USB storage drive
- Again, videos do NOT need to be converted first because Air Video can convert on the fly
- Converting physical DVDs to electronic form is out of scope for this Instructable
Basic A/C inverter, capable of powering your laptop, wifi router and if necessary, the USB storage drive at the same time
- Something like this should work just fine if you don't already have one

And finally, if you don't have an iPod Touch, iPhone, or iPad to stream videos to, I'm sorry to say that you might as well just stop here. Air Video is the magic sauce in this setup and it only streams to iOS devices at this time.

Step 2: Hardware Setup

The beautiful thing about this setup is that it can all be done in advance of your trip.

WiFi Router
I use a Linksys WRT54G Router setup as a basic WiFi access point (AP). While I run the open source “dd-wrt” firmware on this router, the stock firmware should also work just fine as we’re not doing anything special with the configuration. Any router setup as an access point should work. Ideally, you should setup the access point so it has the same SSID, encryption, and password as what you use at home. This way every device will just “work” without any additional configuration provided you have already set them up on your home network. Follow the instructions for your particular router to set it up.

Step 3: Software Setup

AirVideo
Your central video serving device must be running “Air Video” server. This is a free software available from http://www.inmethod.com/. It works on both Mac and PC platforms. It is recommended that you setup the server with a secure password required to access your videos (under the Settings tab).

Each remote device must have the Air Video client installed. It is recommended that you purchase the “professional” version which is very reasonably priced. If all of your devices share the same iTunes account then this means just one purchase for all devices. See the requirements step for links.

Your video library can be completely loaded on your laptop or attached in a USB storage device (or both). You can have multiple locations to serve videos, as in multiple external USB drives, or multiple folder locations on your centralized server. You must configure Air Video server to point to these locations to serve the videos (follow the Air Video install instructions to do this). The process for converting videos from physical DVD to electronic form is out of scope for this tutorial.

Congratulations. You’ve now setup a local area network within your car. Granted, none of the machines can actually access the Internet*, but they can all see each other on the network which is all we need for this setup to work.

* Note: It is possible to set this up to all machines have access to the Internet as well, providing at least one device can be setup with Internet tethering. That is out of scope for this article but if you’re interested let me know as I’ve done this before as well.

Step 4: Go!

Fire it up!
Power on your WiFi router in the car. Note that nothing needs to be connected to the router assuming you’ve already configured it to be an access point. The only cable going in to your router is the power.

Power on your “centralized” PC or Mac. Connect to the WiFi access point in your car and then make sure Air Video server is running (it does not launch automatically on Mac, but can be configured to do so on Windows). It is recommended that your PC or Mac have the power supply connected, just so it does not attempt to go in to “sleep mode” while on battery.

Each user can then connect to the same WiFi access point and launch the Air Video client program. They can easily “search” for available servers on the local network. The machine name of your host should show up (if it doesn't see the last step for troubleshooting). Upon selecting it, the user will be prompted for a password if one was configured. Passwords are saved so they will not need to be entered every time. You can set this up in advance and then your kids will not be promoted for a password going forward.

Upon connecting you can browse the movie folder structure just as if you were on the PC or Mac. Select the movie you want to play. If the movie is not in a Apple “native” format, it will allow you to “Play with Live Conversion”. I’ve had great success with this. If you do convert movies it will require a little less CPU next time you play it, but that also makes an additional copy of the newly converted movie. I don’t bother converting movies because converting them on the fly works extremely well, even with multiple clients doing so at the same time.

And there you have it. Each person can now connect to your centralized server, select the movie THEY want to watch, and watch, pause, stop, or even switch movies without affecting anyone else. I've tested this with FOUR iOS devices all pulling separate videos simultaneously and converting them on the fly. It worked flawlessly with no video or audio hesitation on any of the devices. My Air Video Server was a Mac Book Pro with a 2.3 GHz Intel Core i5 and 4 GB of memory.

I hope this little tutorial has been helpful for everyone. I know this setup is a huge hit with my family and works like a charm every time.

Step 5: Additional Stuff

Other options and improvements that can be made on your “portable” media network are as follows.

AppleTV
Adding an AppleTV allows even more flexibility in your secluded network.

Use “AirPlay” to play movies from your MacBook or PC to the AppleTV
Airplay allows kids to play music and videos from their iPod Touches or iPhones
AppleTVs are great to use in hotels provided you bring along a HDMI cable. You will more than likely not be able to rent or stream videos from sources like Netflix due to restricted bandwidth, but you can stream videos from your centralized PC, iPod, iPhone, or iPad using AirPlay quite well.

Shared Hotel Access
Isn’t it annoying how most hotels require each device to sign-in, sometimes every day, or the few left that charge for access will charge by device connection? Well you can use the same method to get multiple devices on the network within minutes. Simply connect to hotel network using a physical came and your laptop. Once connected (and you have agreed to any terms of service required), unplug the network cable and plug it into the WAN port of your router. If all goes well, you can now connect every device in your hotel room to your secure wireless access point. It is very important that you secure your connection in this case (with WPA2 or greater with a secure password) so that other hotel guests do not simply hop on your connection and start consuming your already limited hotel bandwidth.

Step 6: Tips, Tricks, and Troubleshooting

Below are various tips, tricks, and troubleshooting notes in case you're having trouble.

While not necessary, it is highly recommended that you use the same SSID, security (such as WPA2), and passwords as that which you use at home. This way most of your devices will simply connect without any additional interaction beyond the AirVideo server password.
If you have space on the hard drive of your central PC or Mac, copy the movies there, even if temporary. This will require less power to operate, thus putting less strain on your inverter. Plus, it’s one less device to manage while traveling.
Use descriptive file names for your movies. This way users can quickly and easily determine what the movie is prior to clicking on it.
If you're having trouble connecting to the Air Video server, temporarily disable your Windows or Mac firewall. This is fairly safe to do while on your own password protected private network (assuming you trust all your devices), but just don't forget to re-enable when you reach your destination!
If you have a phone that normally connects to your home network, you should turn off WiFi while traveling because it will be unable to access the internet to get mail while on the road. While connected to your in-car WiFi network it will not attempt to use your cell phone providers network. If that is not an issue to you then don’t worry about it. You'll still get calls just fine.
I recommend limiting the use of electronic devices while traveling with kids. If you don't, they won't be taking in some of the sights from your trip which can be part of lasting memories!