Over the last few years, digital video has become widespread both on the Internet and at home. Internet television and various web sites regularly transmit video material. A digital video camera or a simple web camera is commonplace. No longer are you restricted to simply watching digital video on a DVD.

With a PC and some software, you can record video from different sources, such as Internet web sites (e.g. Internet television), video displayed on your screen, digital and Web cameras, TV tuners, VHS video recorders, and many others. Recorded video can be edited, saved, and used for creating your own collections. With recent software developments, you do not require any special skills to work with video.

The main requirement to work with digital video is a powerful PC. To record from a VHS video recorder, analog video camera, or a DVD player, your computer should have either an external video capture device (e.g. connected through a USB or FireWire port), or a special video capture card. Alternatively, a computer's video card or TV tuner can be equipped with corresponding video input to connect these devices. To capture digital video from a digital DV camera without any loss in quality, a computer should support IEEE 1394 (FireWire) input.

System requirements for working with video

Video files can take up a lot of space, and this requires that your computer is configured accordingly. Using a codec to compress or decrease the size of a video file requires a high-powered processor. Otherwise, the compression can take many hours, or may not even be possible (for example, when recording in real time).

Digital video being captured without compression consumes huge amounts of hard drive space (76 GB or greater for every hour of footage). Therefore, it is recommended you apply a video codec when capturing video. It is better for the codec to have a small compression factor and allow minimal quality loss. The faster the processor, the more complex type of compression can be applied "on the fly", which saves more space on your hard drive. However, even very high-powered computers may be unable to encode video "on the fly" when using some codecs, especially for high-resolution video recordings. Further processing will also depend on your computer's configuration.

The process of capturing video does not make any special demands on a computer's RAM. However, some modern encoders (and decoders) require this to be taken into account.

For capturing video without compression at a resolution of 768x576 pixels and a frame frequency of 25 frames per second, one second of footage will occupy about 22 MB of hard disk space. Similarly, 1 hour will occupy about 76 GB. To record such a video stream requires a hard drive with a high capacity and a high data transfer rate.

To work with Total Recorder's Video Add-on, you also require Windows with DirectX version 9.0, or later, installed. You can download the latest version of DirectX from the Microsoft website.

General recommendations for recording (capturing) video

To capture video, you need to specify several video parameters, including the resolution (size) of the captured region, frame frequency, and recording format for audio and video.

When capturing video from a device (e.g. capture card, TV tuner, web camera, etc.), the video resolution and frame frequency are specified in the device's settings. When capturing from a screen, resolution is defined by the size of the captured region you specify in the Video parameters dialog box. For more information about setting resolution, frame frequency, or video recording format in Total Recorder's Video Add-on, see How to Record Video from Video Devices and How to Record Video from a Screen or Software Player Using Total Recorder's Video Add-on.

Video resolution (size of capture area) for digitization

When digitizing interlaced video that you plan to play on a TV screen (e.g. video from a TV tuner, a DV camera, or the analog input of a video card), it is very important to set full vertical resolution: 576 lines for PAL or 480 lines for NTSC. To capture a recording with a lower quality, you can use half the vertical resolution: 288 and 240 lines respectively. Using any other vertical resolution will not allow you to play back the recording with an acceptable level of quality or to later apply a deinterlace function to the recorded file. For more information on "Interlace" problems, see Troubleshooting Tips when Working with Video.

When capturing video from a screen, where you are allowed to select the resolution, it is recommended you set both the width and height of the captured area to be a multiple of 16 or 32 pixels since many codecs have special requirements for these parameters. It should be at least a multiple of 4. Odd values should be avoided all together.

It is not recommended you use a resolution higher than 768x576 unless absolutely necessary since this leads to a high load on your processor and requires an enormous amount of hard drive space during the capturing process. Choosing a lower image resolution (e.g. 320õ240 or less) can reduce the load on your processor and hard drive. For standard quality video recordings, it is usually sufficient to set the resolution to about 320õ240. This corresponds approximately to the quality of a VHS video recording. For video recordings of a higher quality, use a resolution of about 640õ480. This corresponds approximately to the quality of a DVD video.

Frame frequency

For a high-quality video capture, the frame frequency is usually set to 25 or 30 frames per second. It is not recommended you set the frame frequency higher than 30 frames per second since this leads to a drastic increase on processor load and hard drive requirements.

If the quality of a recording is not very important, you can use 15 frames per second. This will reduce the size of the target file and the load on your processor but the recorded video can lose some fluency.

About video formats

Captured video is stored in a file on your hard drive. The format of this file is referred to as a "container". There are many types of containers, including the following: AVI (Audio and Video Interleaved), ASF (Advanced Streaming Format), MPEG1/2 (with file extensions mpg/mpe/vob), OGG Media (ogg), Real Media (rm/rv/ram), QuickTime (mov/qt), and others.

Total Recorder supports two popular containers: AVI (with a file extension of "avi") and ASF (with file extensions of "asf" or "wmv"). For more information on selecting a container for the Video Add-on, see How to Record Video from Video Devices and How to Convert Video Using Total Recorder's Video Add-on.

AVI container. This format is used for recording both video streams compressed by different codecs, including the most popular MPEG-4 codecs (e.g. DivX), and video files captured directly from a DV (Digital Video) camera without any loss of quality.

ASF container. This format is developed by Microsoft Corporation. There are a number of Windows Media Video codecs for this container. This format is abbreviated to WMV.

Ways of encoding video

When setting video recording parameters, you can select the type of compression (codec). Video is recorded directly to the final file. Although the size of this file will not be too large, you will need a very high-powered computer. Otherwise, the quality of the file will not be satisfactory.

It is recommended you divide the process of capturing and encoding into two stages: intermediate video compression during capturing, and final video compression performed after the video data has been captured and an AVI file is saved on your hard disk. If you have a high powered computer, or the quality of the recorded video is not very important, you can omit the first stage and use only final video compression.

If you capture video that has already been compressed (e.g. from a DV camera), there is no need to apply any compression during recording. The initial quality of the material is preserved when transferring it onto a hard drive. You can then decrease the size of the recording by applying a codec with a higher degree of compression.

Intermediate video compression

As mentioned previously, when capturing uncompressed video with a resolution of 768x576 pixels and a frame frequency of 25 frames per second, one hour of footage occupies about 76 GB of hard disk space. Intermediate compression, with the help of special video codecs, can make this size several times less. The main advantages of intermediate video compression are a small demand for computer resources, minor effects on the image quality, and fast and easy access to key frames for editing.

For intermediate compression, the AVI container is normally used and one of the following codecs applied:

HuffYUV

HuffYUV is a lossless video codec, and it is available free of charge. The latest version of the codec can be downloaded from this page.

The degree of compression of the HuffYUV codec is not very high. It allows you to only halve the video size. Since the codec employs a lossless algorithm, it does not decrease the video quality.

To apply the codec, you can normally use its default settings.

MJPEG

Codecs of this type encode each frame independently. Frames are compressed by applying a lossy algorithm using JPEG compression, which is widely used to compress photographs. If you deal with perfect-quality video, these codecs allow you to compress a stream by a factor of 3 or 4. The most popular software employing this algorithm are the codecs from Pegasus Imaging Corp and Morgan Multimedia. These codecs are not available free of charge.

For the codec from Pegasus (PICVideo MJPEG), it is recommended you set the quality level to be equal to 19 and leave the other parameters as defaults.

The latest versions of codecs from "Morgan Multimedia" let you apply a deinterlace filter to an analog video during the capturing process.

Other codecs, such as DivX or XviD, are not recommended to be applied in real time, since they require many more computer resources. Applying these codecs directly during the capturing process may lead to a large number of dropped frames or they could actually result in lower quality video. These codecs are intended for performing final video compression with a high image quality and are not able to work in real time.

If you are going to capture video with intermediate compression, it is better to first capture the audio in an uncompressed format. You can then edit the resulting file with greater precision. Also, recording in uncompressed format reduces the load on your processor, since there is no need to compress sound in real time. This is very important when capturing video. You can compress the edited audio stream afterwards during the final compression of the video file.

Final compression of video and audio

After video data has been captured and an AVI file is saved on your hard disk, you can edit it (for example, to delete all fragments that you don't need) and perform final compression of audio and video. You can choose either the AVI or WMA container for final compression. If you choose the AVI container, we recommend you use MP3 for audio compression. If you choose the WMV container, we recommend you use Windows Media Audio for audio compression.

For AVI format, MPEG-4 codecs are the most popular since they guarantee high-quality video with a relatively small file size. For final video compression, you can use one of the free codecs supplied with Windows, such as "Intel Indeo Video R3.2". However, for the same size file, the image quality using these codecs is less than the quality using MPEG-4 codecs, such as DivX or XviD. Also, one of the important advantages of the DivX and XviD codecs is their compatibility with domestic DVD players.

The VP6 and VP7 codecs from On2 Technologies have recently become widespread. These codecs provide high-quality encoding (no worse than DivX and XviD) and are especially suited for low bit-rate encoding.

As a rule, all codecs that guarantee a high image quality also support two-pass encoding in which an initial file is processed by a codec two times. Although two-pass encoding takes more time, it results in much better encoding quality. For more information on applying two-pass encoding, see How to Convert Video Using Total Recorder's Video Add-on.

The following are some popular video codecs for AVI:

DivX

The latest version of the DivX codec can be downloaded from its developer site. The codec provides a deinterlace function you can use if you capture interlaced video. It is highly compatible with domestic DVD players. For more information on this codec, see How to Convert Video Using Total Recorder's Video Add-on.

XviD

The link to download the latest version of the XviD codec can be found at the its developer site or at the Free Xvid Codec Download. The codec is compatible with domestic DVD players and it is distributed free of charge.

VP6

VP6, and the newer VP7 codec, can be found at the following links:
http://www.free-codecs.com/download/VP6.htm
http://www.free-codecs.com/download/VP7.htm

The codec provides a deinterlace function and it is currently distributed free of charge. The disadvantage of this codec is its incompatibility with domestic DVD players.

About WMV format

To encode in WMV format, Microsoft recommends you use the latest versions of the Windows Media Video codecs since they provide maximum video quality. Currently, these are the Windows Media Video 9 Series codecs. However, if your computer is not powerful enough, you can use the WMV 7 or WMV 8 Series codecs.

WMV codecs support a deinterlace function but they not very compatible with home DVD players. For detailed information about the latest versions of Windows Media Video codecs, refer to Microsoft's official website.