Intra-frame coding is a data compression technique used within a video frame, enabling smaller file sizes and lower bitrates, with little or no loss in quality. Since neighboring pixels within an image are often very similar, rather than storing each pixel independently, the frame image is divided into blocks and the typically minor difference between each pixel can be encoded using fewer bits.
Intra-frame prediction exploits spatial redundancy, i.e. correlation among pixels within one frame, by calculating prediction values through extrapolation from already coded pixels for effective delta coding. It is one of the two classes of predictive coding methods in video coding. Its counterpart is inter-frame prediction which exploits temporal redundancy. Temporally independently coded so-called intra frames use only intra coding. The temporally coded predicted frames (e.g. MPEG's P- and B-frames) may use intra- as well as inter-frame prediction.
Usually known adjacent samples (or blocks) are above, above left, above right, and left (A–D).
Usually only few of the spatially closest known samples are used for the extrapolation. Formats that operate sample by sample like Portable Network Graphics (PNG) can usually use one of four adjacent pixels (above, above left, above right, left) or some function of them like e.g. their average. Block-based (frequency transform) formats prefill whole blocks with prediction values extrapolated from usually one or two straight lines of pixels that run along their top and left borders.
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. In other words, no temporal processing is performed outside of the current picture or frame. Non-intra coding techniques are extensions to these basics. It turns out that this block diagram[clarification needed] is very similar to that of a JPEG still image video encoder, with only slight implementation detail differences.
Inter frame has been specified by the CCITT in 1988–1990 by H.261 for the first time. H.261 was meant for teleconferencing and ISDN telephoning.
Data is usually read from a video camera or a video card in the YCbCr data format (often informally called YUV for brevity). The coding process varies greatly depending on which type of encoder is used (e.g., JPEG or H.264), but the most common steps usually include: partitioning into macroblocks, transformation (e.g., using a DCT or wavelet), quantization and entropy encoding.
intra, frame, coding, other, uses, iframe, disambiguation, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, needs, additional, citations, verification, pl. For other uses see IFrame disambiguation This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Intra frame coding news newspapers books scholar JSTOR March 2017 Learn how and when to remove this template message This article may be too technical for most readers to understand Please help improve it to make it understandable to non experts without removing the technical details June 2019 Learn how and when to remove this template message Learn how and when to remove this template message Intra frame coding is a data compression technique used within a video frame enabling smaller file sizes and lower bitrates with little or no loss in quality Since neighboring pixels within an image are often very similar rather than storing each pixel independently the frame image is divided into blocks and the typically minor difference between each pixel can be encoded using fewer bits Intra frame prediction exploits spatial redundancy i e correlation among pixels within one frame by calculating prediction values through extrapolation from already coded pixels for effective delta coding It is one of the two classes of predictive coding methods in video coding Its counterpart is inter frame prediction which exploits temporal redundancy Temporally independently coded so called intra frames use only intra coding The temporally coded predicted frames e g MPEG s P and B frames may use intra as well as inter frame prediction Usually known adjacent samples or blocks are above above left above right and left A D Usually only few of the spatially closest known samples are used for the extrapolation Formats that operate sample by sample like Portable Network Graphics PNG can usually use one of four adjacent pixels above above left above right left or some function of them like e g their average Block based frequency transform formats prefill whole blocks with prediction values extrapolated from usually one or two straight lines of pixels that run along their top and left borders 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 In other words no temporal processing is performed outside of the current picture or frame Non intra coding techniques are extensions to these basics It turns out that this block diagram clarification needed is very similar to that of a JPEG still image video encoder with only slight implementation detail differences Inter frame has been specified by the CCITT in 1988 1990 by H 261 for the first time H 261 was meant for teleconferencing and ISDN telephoning Contents 1 Coding process 2 Applications 3 See also 4 External linksCoding process EditData is usually read from a video camera or a video card in the YCbCr data format often informally called YUV for brevity The coding process varies greatly depending on which type of encoder is used e g JPEG or H 264 but the most common steps usually include partitioning into macroblocks transformation e g using a DCT or wavelet quantization and entropy encoding Applications EditIt is used in codecs like ProRes a group of pictures codec without inter frames See also EditVideo compression I Frame Delay Inter frame Group of pictures application of frame types Motion compensationExternal links Edit nbsp Wikimedia Commons has media related to Intra frame coding http www cs cf ac uk Dave Multimedia node248 html nbsp This computing article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Intra frame coding amp oldid 1069597421, wikipedia, wiki, book, books, library,
