Media Editing Terminology
These are some of the terms related to media editing and capturing which are used throughout this document.
A Timeline is a graphical representation of media files, video effects or video transitions on a time scale. The time scale runs horizontally on the Timeline. A Timeline consists of multiple tracks.
A Group categorizes tracks. There are four types of groups in Video Edit Magic:
- Video Group
- Audio Group
- Effects Group
- Transition Group
Sources in tracks that belong to the same group are represented by distinct colors in the Timeline.
A Track is a linear sequence of clips, effects, or transitions. Each track is associated with a particular group. A track consists of one or more sources.
A source is any media file, video effect or video transition added to and represented in a track of the Timeline. A source is added to a track of a particular group. For instance a video file that consists of both video and audio is added separately to a video track and an audio track (This one file might be called two sources.). Sources can be edited individually.
Video and audio are called "media". A media file may contain both video and audio, or only one.
A stream is video or audio data that composes a media file. A single media file may contain one or more video and/or audio streams.
- Dimension: Measured in pixels, the dimensions of a video are the height and width. For example, a video of 320 x 240 pixels is 320 pixels wide (width) and 240 pixels tall (height).
- Color Depth: Measured in bits per pixel (bpp), color depth of a video is the amount of color information it stores per pixel. High color videos are typically of 24bpp. Lower color depth can make pictures and video look "cartoon" and less realistic.
- Frame Rate: Measured in frames per second (fps), frame rate of a video is the number of individual video frames that are displayed per second. Higher frame rates are used to shoot high motion videos.
- Bit Rate: Measured in bits per second (bps) or kilobits per second (Kbps), bit rate of a video is the amount of data that can be transferred in one second. Bit rates are directly related to frame rates.
- Key Frame Rate: The key frame rate of a video is the number of non-key frames that are allowed before a key frame is required. For instance, a key frame rate of 40 means that at least every 40'th frame must be a key frame. Key Frames affects video seeking capabilities and are also used in some high-end compression techniques. In general, more key frames will improve quality at the expense of somewhat larger files.
- Frequency: Measured in Hertz (Hz) or Kilohertz (KHz), frequency of an audio is the number of audio samples transferred in one second.
- Bit Rate: Measured in bits per second (bps) or Kilobits per second (Kbps), bit rate of audio is the amount of audio data that can be transferred in one second.
- Channels: An audio channel forms a part of an audio stream. Mono channel audio have 1 channel per audio stream while stereo has 2.
AVI (Audio Video Interleaved)
AVI is a simple format that is best suited for editing purposes. Video Edit Magic is capable of making movies in AVI format.
Media files that save uncompressed video, though good in quality, can take up huge amounts of disk space. Using a Compressor/Codec significantly reduces the size of AVI files. Video Edit Magic lists all the Compressors/Codecs installed on a PC. These Compressors/Codecs can then be used to compress AVI files. The compression level achieved depends on the properties of the video being compressed and the Compressor/Codec in use. (Codec="COmpressor/DECompressor)
WMV/WMA (Windows Media Format)
Windows Media Format is a high end video format that is characterized by small size and streaming capabilities. Video files saved in Windows Media Format have the extension WMV (Windows Media Video) and Audio files saved in Windows Media Format have the extension WMA (Windows Media Audio). Some Windows Media Format files may also have the extension ASF (Advanced Streaming Format).
MBR (Multi Bit Rate)
Multi Bit Rate is a type of Windows Medai Format file that contains multiple video and/or audio streams encoded at varying bit rates. This enables MBR media files to be viewed optimally over a wider range of bandwidth. For example a video with 7 video streams encoded at bit rates from 16Kbps to 128Kbps can be viewed by audience with internet connection speeds from 16Kbps to 128Kbps. A streaming server and client (like Windows Media Player and Windows Media Server) will pick the best speed to stream the MBR file at—the speed that will give the best possible quality at the available bandwidth, without the pauses you would get if too high a bit rate was chosen. Files created for playback on the local computer (not across a network) are typically not MBR.
A Video/Audio Profile is a file that describes how to create media files with particular properties. When making Windows Media Format files, an appropriate profile is selected. The profiles is read and a file is made following the definition in it. Each profile is intended for a particular audience, and videos made using a profile targets the intended audience. Video Edit Magic is able to list both system and custom profiles in a PC.
Capture Devices is a collective term used for devices connected to your PC that capture video or sound. Web Cameras (WebCam), DV Cameras, etc. qualify as video capture devices while microphones are audio capture devices. Video Edit Magic can use and capture from all capture devices.