Dictionary
Some terms used in the area of Audio/Video and their meaning.
Aspect Ratio
The ratio of width to height of a video.
Bitrate
The number of bits of data to be played per second.
Chroma
Greek for color, the part of a video file or signal that encodes the color portion.
Codec
A part of the program which understands a type of video or audio (short for Compression/Decompression)
Decode
To understand and play a file, VideoLAN needs to decode it. It does this with a decoder.
Deinterlacing
Deinterlacing is the process of converting interlaced video (a sequence of fields) into a non-interlaced form (a sequence of frames). This is a fundamentally impossible process that must always produce some image degradation, since it ideally requires "temporal interpolation" which involves guessing the movement of every object in the image and applying motion correction to every object.
Demuxing
Encode
ES
An Elementry Stream, a single channel of audio, video or subtitles (without a container).
FourCC
Framerate
The number of frames of video displayed (or encoded to be displayed) per unit time, usually expressed in frames per second (fps) or Hertz (Hz). One Hertz is equivilant to one frame per second.
IDCT
Keyframe
A frame of video which is stored as a complete image, not just as the changes from the previous image.
Motion Compensation
Part of the video compression process. New frames normally store changes in the image since the previous frame. If the scene is moving as a whole (such as panning), motion compensation moves the reference frame to line up with the new frame. This means that there are less changes to be stored since the previous frame, and so less data needs to be stored.
Muxing
Overlay
Displaying an image on top of the video
Packetizing
Post Processing
PCR
PS
Abbreviation for Program Stream.
PTS
Sample rate
Usually used with audio, the frequency at which a signal is digitally sampled, usually expressed in Hertz (Hz) or kiloHertz (kHz). One Hertz is equivilant to one sample per second, One kiloHertz is a thousand (1000) Hertz.
Transcode
Transcoding is changing the format of a file.
TS
Abbreviation for Transport Stream.
