How does interframe compression work?
Interframe compression uses a variety of techniques to encode the changes from one frame to the next. A motion vector tells the codec to take some pixels from one frame, and move them a little bit for the next frame. In doing so, the codec avoids wasting bits sending the same data twice.
What is spatial compression?
Spatial-compression meaning Filters. Reducing digital video file sizes by compressing the pixels within each frame independently. Also known as the “intraframe” method. Contrast with temporal compression.
What is temporal compression?
Temporal compression is a technique of reducing compressed video size by not encoding each frame as a complete image. The frames that are encoded completely (like a static image) are called key frames.
What is interframe redundancy?
Interpixel temporal redundancy is the statistical correlation between pixels from successive frames in video sequence. Temporal redundancy is also called interframe redundancy. Temporal redundancy can be exploited using motion compensated predictive coding.
What is the difference between intraframe and interframe coding?
Intra-frame means that all the compression is done within that single frame and generates what is sometimes referred to as an i-frame. Inter-frame refers to compression that takes place across two or more frames, where the encoding scheme only keeps the information that changes between frames.
What is the difference between temporal and spatial video compression?
Spatial (or intraframe) compression takes place on each individual frame of the video, compressing the pixel information as though it were a still image. Temporal compression relies on the placement of key frames interspersed throughout the frames sequence.
What is lossless and lossy compression?
Compression can be lossy or lossless . Lossless compression means that as the file size is compressed, the picture quality remains the same – it does not get worse. Also, the file can be decompressed to its original quality. Lossy compression permanently removes data.
What is spatial and temporal compression?
Is interframe coding lossless?
The term intra-frame coding refers to the fact that the various lossless and lossy compression techniques are performed relative to information that is contained only within the current frame, and not relative to any other frame in the video sequence. Inter frame has been specified by the CCITT in 1988–1990 by H.
What is an inter frame in video compression?
An inter frame is a frame in a video compression stream which is expressed in terms of one or more neighboring frames. The “inter” part of the term refers to the use of Inter frame prediction. This kind of prediction tries to take advantage from temporal redundancy between neighboring frames enabling higher compression rates.
Does interframe coding compress data?
Interframe coding often provides substantial compression because in many motion sequences, only a small percentage of the pixels are actually different from one frame to another. However, it depends entirely on the content. A room full of people dancing will compress less than a person sitting in a chair talking.
What is an interframe space (IFS)?
What is an Interframe Space (IFS)? An interframe space, or IFS for short, is part of a greater process which is used to avoid a collision with other frames. It is basically a period of time that every Wi-Fi device (station) must wait before it transmits an 802.11 frame.
What is PCF Interframe Space (PIFS)?
The Point Coordination Function (PCF) Interframe Space (PIFS) was for use specifically in PCF implementations. According to the 802.11-2016 standard, “The PCF mechanism is obsolete.” At this time, it is not all that useful to understand so will not be covered here.