Dear Lifehacker,
I know a lot of video players (like PotPlayer) can play any video file out there, but why are there so many video formats in the first place? Is there a real difference between DivX and XviD, or MP4, and MKV? When I rip a DVD, or go hunting for downloads, which format is the best to use?

Sincerely,
Confused About Codecs

Dear Confused,
The world of video formats can be pretty confusing, but there are only a few things you really need to know. First, it's important to note that a video format is more than just its file extension. Extensions like AVI are not, in fact, video codecs—they're containers. A container is the file format which can use multiple different codecs—such as DivX or x264—to compress a certain standard of video—such as MPEG-4 or H.264, respectively—into a hard-drive friendly amount of space. Here's what you need to know about both codecs and containers, and what that means for the videos you rip yourself.

What Is a Codec?

Most of the video you'll come across is compressed, meaning its been altered to take up less space on your computer. For example, a regular Blu-Ray disc usually takes up around 30 or 50GB of space—which is a lot for a normal person to download or store on their hard drive. So, we compress movies to make them more manageable, usually with some loss in video quality.

A codec compresses and decompresses data. It interprets the video file and determines how to play it on your screen. Your computer comes with many codecs pre-installed, though you can install codec packs for wider support, or a program like VLC or PotPlayer (which we prefer to codec packs). Some examples include:

• FFmpeg (which includes formats like MPEG-2, the format in which DVDs are stored, and MPEG-4, which is the video format Apple uses in the iTunes store)
• DivX, which works with a certain type of MPEG-4 file, and was often used to rip DVDs in the pre-HD era
• XviD, an open source version of DivX, popular among movie pirates
• x264, which compresses H.264 videos (Also known as MPEG-4 AVC), and is very popular for high definition videos

There are a lot of different codecs out there, and it can get really confusing with all the different versions of MPEG standards. These days, you really only need to concern yourself with a few—which we'll talk about in a couple minutes.

What Is a Container?

A container is, essentially, a bundle of files. Usually a container consists of a video codec and an audio codec, though it can also contain things like subtitles. Containers allow you to choose one codec for your video and one for your audio, which is nice—that way, you can choose to use the high-quality DTS audio, or compress your audio to something like MP3 for even more space savings. It just gives you a bit more control over how you record your videos or rip your movies. Popular containers include:

• AVI
• Matroska (which uses the extension MKV)
• MP4 (which has been popularized by Apple in the iTunes Store—note that this can also come with the M4V extension, but the container is the exact same)
• MOV (which was created by Apple)

The main difference between different containers is not only the codecs they support but what other features they support—like subtitles or chapters. These days, MKV is an extremely popular container, mainly because it supports nearly any video codec under the sun, as well as a ton of extra features (plus it's open source).

So Which Should You Use?

These days, you'll only really come across a few different codecs and containers as you browse the web for video. DivX and XviD (DivX's open source counterpart) are popular for standard-definition videos, like ripped DVDs, but are mostly outdated, so I wouldn't use them to rip your own DVDs. Handbrake, our favorite DVD ripper and video encoder, supports three video codecs (which you can see under the "Video" tab) and two containers (which you'll find under "Output Settings"). H.264, which Handbrake uses by default, will give you the best quality, though if you don't care about quality, MPEG-4 will probably compress faster. As for containers, both MKV and MP4 support high quality H.264 video, but in general we prefer MKV for almost everything, since it has a few more extra features, supports higher quality audio, and is open source. The one downside of MKV is that it isn't as well supported by certain programs and devices. So, if you're putting these videos on your iPad, Apple TV, or Xbox 360, for example, you'll want to go with the more widely supported MP4. If you're watching them in VLC, PotPlayer, XBMC, or another video player that supports MKV, then MKV is the way to go.

That's a lot of information to throw at you in a few paragraphs, but like we said—despite how big and confusing the world of video is, a lot of those codecs are outdated, and you only really need to concern yourself with a few. If you want a more detailed comparison, check out Wikipedia's Comparison of Video Codecs, Comparison of Container Formats, and its entry on MPEG for more info on all the different variations of the MPEG standards of video compression.

Sincerely,
Lifehacker

Photo remixed from Péter Gudella.

VLC 2.0 is awesome, but if you've tried to rip DVDs with Handbrake after installing it on a Mac, you've probably found that it no longer works. Here's how to fix it.

Handbrake can't rip DVDs on its own; you need VLC installed to provide the necessary DVD decrypting libraries. However, VLC 2.0 changes the code libraries it uses for decrypting, which means Handbrake won't be able to find them—and will throw you an error saying it can't find your VLC installation. The solution, luckily, is very simple: just download the missing library manually. Head to this page and download the libdvdcss.pkg file and run the installer. When it's done, you should be able to rip DVDs again. Alternatively, you can download the libdvdcss.2.dylib file from that page and manually place it in the /usr/lib folder on your Mac. Hit the link to read more.

Fix HandBrake DVD ripping if you've installed VLC 2.0 | Macworld

Upon receiving her new MacBook Air, my mother asked me how she's supposed to watch movies on the plane without a DVD drive. If you've got people asking you similar questions, here are some easy-to-follow instructions for ripping a DVD to your computer.

Ripping a movie to your hard drive can seem like a complicated task, but it's actually pretty simple. There are a lot of ways to do it and a lot of different programs out there, but our favorite method uses a program called Handbrake. It's pretty easy to use, and available on both Windows and Mac. The video above should walk you through the process, but you can follow along with these instructions.

1. Head to Handbrake's homepage and download the program. If you're on Windows, you'll need copy a .DLL file into Handbrake's directory, while Mac users will just need to install VLC on their computer (even if you don't use it to watch videos).
2. Open up Handbrake, and click the Source button. Pick your DVD drive from the list. It will start scanning your DVD, which could take a few minutes, so let it do its thing.
3. When it's done, head to the "Title" drop-down menu in the upper left hand corner of the window. This is where you'll select which part of the DVD you want to rip. In the case of movies, it's usually the longest title, so just pick that one. If you're ripping episodes of a TV show, it's usually the 22 or 44 minute ones, and you'll have to rip them separately.
4. Click the Browse button on the right side of the window. Navigate to where you want to save your movie file, and type in a file name in the box. Click OK.
5. Next, head to the bar on the right labeled "Presets". This is where you'll choose what format the resulting file will be in. If you just want to watch it on your computer, the "Normal" preset is fine. If you want to watch it on something like your iPod or iPhone, though, pick the correct preset on the left.
6. Hit the Start button at the top of the window. This will take awhile, so you'll probably want to find something else to do for a bit.
7. When it's done, you'll get a popup notification. From there, you can watch your movie from where you saved it, or, if you want to sync it to an iPhone or other similar device, just drag it into iTunes' left sidebar, sync your phone, and enjoy the movie!

It seems like a lot of steps at first, but it really isn't very difficult. It's just a matter of picking the right chapter from the DVD and ripping it to the right format. Note that if you're going to be ripping a lot of DVDs, you can head to Tools > Options (or Handbrake > Preferences, if you're on a Mac), and hit "Browse" next to "Default Path" to choose a location for all the other movies you rip in the future. That way, every time you rip, you can skip step 4, and your movie files will always end up in the same place.

Windows/Mac: If you missed your chance to grab MacX DVD Ripper Pro while it was free in October, your second chance came up. The How-To Geek is hosting a give-away special with a license key, so you can grab the app that rips DVDs straight to easily play-able files (and directly to your devices, if you'd like) without paying a dime. Hit the link to grab a serial number and other download details. [How-To Geek]