Ultimate Guide to Playing and Transcoding Downloaded Videos

Posted 12/16/2009 at 9:30am | by Paul Lilly

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Split Large AVI Files with VirtualDub

Maybe you're trying to transfer a ginormous video file from one PC to another that's not connected on a LAN. Or maybe you're trying to back up your movie to multiple CDs or even a USB stick without sacrificing any video quality. Whatever the reason might be, it's pretty simple to split oversized AVI files into multiple chunks, each one playable on its own. Here's how.

You'll need to download and unpack VirtualDub, which you can snag from here. Once up and running, click on File>Open video file and locate your AVI file.

Next, click on Video and select Direct stream copy. This will prevent VirtualDub from re-encoding the entire video, which can take a long time and have a negative impact on quality. Also be sure that Direct stream copy is selected from the Audio menu (it should already be selected by default).

To splice your video in half, take note of numbers running along the bottom, particularly the one all the way to the right. These numbers represent how many frames are in your video, and in our example, there are 7953 frames. To cut our video in half, we'll need to splice it at approximately the 3976 mark. To do this, make sure the slider is all the way on the left-hand side. Click the Set selection start button, as indicated by the arrow above. Next, move the slider to the frame where you want the video to end and click the Set selection end button (directly to the right of the button you just pressed). The slider selection should not be blue.

With your selection in place, go to File>Save as AVI and name your file something like "BirthdayVideo_Part1." Once VirtualDub finishes, repeat the above steps for the second half of your video.

All About Audio

Video playback isn't just about visuals, it's also about the audio. And if you're not an audiophile, this is where things can get a little confusing. Let's go over some common topics.

Mono vs Stereo vs 5.1/7.1

Stereo sound is often used to describe 2-channel audio. Each channel is independent from the other, unlike mono sound, in which audio is pushed through a single channel through two or more speakers. By utilizing two independent audio signals, it becomes possible to recreate the aural perspective and localization of instruments on a stage, whereas that wouldn't be possible with mono.

Image Credit: smartbuyspeakers.com

When you start talking about surround sound, that's where 5.1 audio comes in. This consists of five channels of sound (left, center, right, left surround, and right surround) and one channel for LFE (Low frequency effects), typically handled by a subwoofer. The benefit of this over Stereo or Mono is that you're in the middle of the action. When properly utilized, you would, for example, be able to hear footsteps creeping behind you and hear bullets whizzing by.

Image Credit: smartbuyspeakers.com

As you might have guessed, 7.1 surround sound adds two more audio channels to the mix -- and two more speakers to your home theater setup -- as it splits the surround and rear channel audio into four channels. In this type of setup, you would have two surround speakers ideally placed on each side of you and slightly behind, and two more rear surround speakers placed behind you at an angle.

DTS

Image Credit: firstdtsstudio.hit.bg

You've probably seen DVDs and home theater equipment boasting DTS playback, but what exactly is DTS? It technically stands for Digital Theater Systems, but is used to describe the competing surround sound codec to Dolby Digital. DTS offers up to 5.1 channels of audio. On the technical side, DTS uses a maximum bitrate of 1.5Mbps, which requires less compression and can theoretically product higher quality audio.

Dolby Digital

The competing audio format to DTS, Dolby Digital (DD), otherwise known as AC- 3, is arguably the most popular digital format. Like DTS, DD utilizes lossy data reduction algorithms. The difference is, DTS offers a higher bitrate, but that doesn't necessarily mean DTS sounds better (this is actually a point of heated debate). Dolby contends that its encoding method is more efficient than DTS, and therefore the bitrate doesn't need to be as high. Both standards work on the principal of removing information that is inaudible or otherwise won't be missed.

Like DTS, there are many forms of Dolby Digital, including EX, Surround EX, Live, Plus, and TrueHD.

Fun Fact: On film, Dolby Digital uses the space between the sprocket holes to encode information.

Multiple Language Tracks

The reason some videos allow you to choose between English, French, Spanish, and other languages is because they include multiple language tracks. A language track is a separate stream from the surround sound effects, and is also how additional commentary -- usually by the director -- is thrown in.