The screen size on a portable DVD player can range from 7 to 15 inches. As you might imagine, the bigger the screen size, the heavier and bulkier the DVD player. Portable DVD players with 15-inch screens are generally about the same size as a small laptop.

So which screen size should you choose? That depends, in large part, on how you plan to use the DVD player. If you want to use it at home as a backup entertainment device when you have guests, a large screen would probably suit you. But if you want a screen to watch while travelling in a car or on a plane, a smaller size would be more portable and thus more convenient.

A portable DVD player with dual screens gives you two options. You could play the same movie on both screens, or you could watch a different movie on each screen. Families in which two or more children may argue about what to watch can benefit from a dual-screen configuration. Conveniently, headphone jacks are included for both screens.

All DVD players come with one or two headphone jacks. If you plan to use your device to entertain a crowd, be sure to purchase one with built-in speakers as well. For the audiophiles out there, there are some portable DVD players that also have surround sound capabilities.

Portable DVD players with virtual surround sound outputs allow a connection to an entertainment system. Some include the cords to make the connection; others don’t. In the case of the latter, the cords would have to be purchased separately.

If you’re planning to connect the DVD player to a home entertainment system, keep in mind that devices with S-video or component and digital audio outputs offer the best playback. High-definition TVs will require a portable DVD player with an HDMI port, which is a common feature on mid-range to expensive models.

Purchased or rented DVDs will play on any portable DVD player. However, not all models can play back DVDs that you create yourself. If you plan to watch DVDs that you or someone else created (or "burned"), buy a DVD player that can play DVD-R, DVD-RW, and DVD+R formats.

There are now some models that can play both DVD and Blu-ray formats. If you collect Blu-ray discs, be sure to choose a model that explicitly says it plays Blu-ray. Likewise, some players support the CD-R format, which makes it possible for the DVD player to act as a CD player as well.

Some newer models even have an SD card slot, which allows you to view image files or other media stored on an SD card. DVD players with this capability are excellent choices for business presentations or personal slideshows.

All portable DVD players come with a power cord of some kind: AC adapter, USB cord, car adapter. But one of the things that makes a portable DVD player so convenient is its ability to run strictly on battery power. Battery life is an important consideration because it can greatly increase portability. Battery life typically runs from one to five hours, after which you must plug the device in to recharge. The battery will lose power faster the more features you use, especially if the device has wireless capabilities.

Depending on your situation, there are some other features you might appreciate in a portable DVD player. Consider the following.

• Protective carrying case: Some portable DVD players come with a light bag for storage and carrying. Others come with a padded, well-structured case that can hold your DVDs, power cord, and other accessories to make travel easier,

• Headrest mount: Flat-screen DVD players (or those that can fold down flat) fit into these mounts, which can be attached to the back of a headrest.

• Swivel screen: Some portable DVD players come with a swivel screen that can turn a full 360 degrees for easy viewing. This type can often fold down like a tablet as well.

• Versatile viewing options: Some portable DVD players offer several different viewing options. The possibilities include regular viewing, flat tablet-like viewing, and tent viewing. This type of versatility allows you to get a good angle of viewing no matter where you are.  

• Mounting straps: These handy straps hold the DVD player to the back of a car headrest for backseat viewers.

• Gaming: With the purchase of some portable DVD players, you get the ability to download video games through the company website. This type of DVD player should include a removable game controller.

• Remote control: A remote control makes it easy to control the DVD while in the car, especially from the back seat.

• WiFi connectivity: Portable DVD players aren’t always limited to just movies on DVD. With some devices, you can enjoy Netflix and other streaming services when connected to WiFi.

• Bluetooth capabilities: This is a great feature if you want to connect to a wireless speaker.

• Touchscreen: A portable DVD player with a touch screen looks and functions like a tablet. 

• For under $50, you can find a portable DVD player with a seven- to nine-inch screen and a few extras, such as a swivel or flat screen. In this price range, you can usually expect to get three to four hours of battery life per charge.

• Between $50 and $100, you can get a portable DVD player with a screen between 10 and 14 inches. The package may include a remote, swivel screen, SD card slot, USB port, and three to five hours of battery life. You may also see a few inexpensive dual-screen DVD players in this price range, but they tend to not perform as well.

• In the $100 to $200 range, you will find portable DVD players with a variety of features and a wide range of screen sizes. There are high-quality 10-inch dual screens with ultra-thin designs and single-screen models with screens of up to 15 inches. Touchscreen technology, HDMI ports, Blu-Ray, WiFi, and Bluetooth capabilities are more common at this price point.

• For $200 and up, you can find premium portable DVD players that look and act much like tablets in their design and capabilities. Touchscreen, Bluetooth, Airplay, HDMI, FM radio, WiFi, and more can be found at this price range, and battery life tends to hover between three and five hours.

Q. Can I play streaming video on a portable DVD player?

A. Yes, as long as your DVD player has the right capabilities. Of course, it must be WiFi-capable, but if you want to play streaming videos while traveling, you might want a model that can also do AirPlay. To use this feature, you turn a cellphone into a hotspot and connect the DVD player to it. Then, turn on AirPlay mirroring; the material that streams on your cell phone will also stream on your DVD player.

Q. How long does it take to charge a portable DVD player?

A. The length of time it takes for a portable DVD player to charge varies; brand and size play a role in this variation. In general, however, you can expect it to take anywhere from three to six hours.

Q. Do I have to buy a carrying case or headrest mount separately?

A. It all depends on what’s included with your package. Some DVD players come with both a carrying case and a headrest mount, some come with one or the other, and some come with neither.

If you must purchase a case separately, look for something that’s sturdy and/or padded to protect the DVD player while traveling. Check the size of your DVD player before purchasing either a case or headrest mount to be sure it will fit.