Interlaced Video

MPEG-1 and MPEG-ii Video Standards

Supavadee Aramvith , Ming-Ting Sunday , in Handbook of Image and Video Processing (Second Edition), 2005

ii.4.ane Interlaced vs. Progressive Video

Figure 10 shows the progressive and interlaced video scan. In the interlaced video, each displayed frame consists of ii interlaced fields. For example, frame i consists of field ane and field two, with the scanning lines in field ane located between the lines of field 2. On the contrary, the progressive video has all the lines of a moving-picture show displayed in one frame. There are no fields or half pictures as with the interlaced scan. Thus, progressive video requires a college motion picture rate than the frame rate of an interlaced video, to avoid a flickery brandish.

Effigy 10. (a) Progressive scan, (b) Interlaced scan.

The principal disadvantage of the Interlaced format is that when there are object movements, the moving object may announced distorted when we merge 2 fields into a frame. For example, Fig. x shows a moving ball. In the interlaced format, since the moving ball will be at different locations in the two fields, when we put the two fields into a frame, the brawl will look distorted. Using MPEG-1 to encode the distorted objects in the frames of the interlaced video will not produce the optimal results.

Read total chapter

URL:

https://world wide web.sciencedirect.com/science/article/pii/B9780121197926501121

Digital Video Processing

Keith Jack , in Digital Video and DSP, 2008

Interlaced-to-noninterlaced Conversion

In some applications, it is necessary to display an interlaced video signal on a noninterlaced brandish. Thus, some grade of deinterlacing or progressive scan conversion may be required.

Alert!

Note that deinterlacing must exist performed on component video signals (such every bit R′Grand′B′ or YCbCr). Composite color video signals (such equally NTSC or PAL) cannot be deinterlaced straight due to the presence of color subcarrier phase information, which would be meaningless after processing. These signals must exist decoded into component colour signals, such every bit R′G′B′ or YCbCr, prior to deinterlacing.

There are two fundamental deinterlacing algorithms: video mode and pic mode. Video manner deinterlacing tin can be further broken down into inter-field and intra-field processing.

The goal of a good deinterlacer is to correctly choose the best algorithm needed at a particular moment. In systems where the vertical resolution of the source and display do not match (due to, for example, displaying SDTV content on an HDTV), the deinterlacing and vertical scaling can be merged into a single process.

Video Mode: Intra-Field Processing

This is the simplest method for generating additional scan lines using merely data in the original field. The computer industry has coined this technique every bit bob.

Although at that place are two mutual techniques for implementing intra-field processing, scan line duplication and scan line interpolation, the resulting vertical resolution is always limited by the content of the original field.

Browse Line Duplication

Browse line duplication simply duplicates the previous agile scan line. Although the number of agile browse lines is doubled, in that location is no increment in the vertical resolution.

Scan Line Interpolation

Scan line interpolation generates interpolated scan lines between the original agile scan lines. Although the number of active scan lines is doubled, the vertical resolution is not.

The simplest implementation uses linear interpolation to generate a new scan line between two input scan lines. Better results, at additional cost, may be accomplished by using a FIR filter:

Fractional Ratio Interpolation

In many cases, at that place is a periodic, but non-integral, human relationship between the number of input browse lines and the number of output scan lines. In this example, fractional ratio interpolation may be necessary, similar to the polyphase filtering used for scaling only performed in the vertical direction. This technique combines deinterlacing and vertical scaling into a single procedure.

Variable Interpolation

In a few cases, there is no periodicity in the relationship between the number of input and output scan lines. Therefore, in theory, an space number of filter phases and coefficients are required. Since this is not feasible, the solution is to utilize a large, simply finite, number of filter phases. The number of filter phases determines the interpolation accuracy. This technique also combines deinterlacing and vertical scaling into a single procedure.

Video Mode: Inter-Field Processing

In this method, video data from more than than one field is used to generate a single progressive frame. This method tin provide higher vertical resolution since it uses content from more than a unmarried field.

Field Merging

This technique merges two consecutive fields together to produce a frame of video. At each field fourth dimension, the active browse lines of that field are merged with the active scan lines of the previous field. The event is that for each input field time, a pair of fields combine to generate a frame. Although simple to implement, the vertical resolution is doubled only in regions of no movement.

Moving objects will have artifacts, likewise called combing, due to the fourth dimension departure between 2 fields—a moving object is located in a different position from 1 field to the adjacent. When the 2 fields are merged, moving objects will accept a double image.

It is common to soften the paradigm slightly in the vertical management to attempt to reduce the visibility of combing. When implemented, it causes a loss of vertical resolution and jitter on motion and pans.

Insider Info

The estimator industry refers to this technique every bit weave, simply weave likewise includes the changed telecine process to remove any three:2 pull-downwardly present in the source. Theoretically, this eliminates the double image artifacts since two identical fields are now being merged.

Motion Adaptive Deinterlacing

A good deinterlacing solution is to use field merging for notwithstanding areas of the pic and scan line interpolation for areas of motion. To accomplish this, movement, on a sample-by-sample footing, must be detected over the unabridged motion picture in real time, requiring processing several fields of video.

As 2 fields are combined, total vertical resolution is maintained in still areas of the picture, where the eye is most sensitive to detail. The sample differences may have whatever value, from 0 (no motion and dissonance-free) to maximum (for case, a change from full intensity to blackness). A choice must be made when to use a sample from the previous field (which is in the incorrect location due to motion) or to interpolate a new sample from adjacent scan lines in the current field. Sudden switching betwixt methods is visible, then crossfading (too chosen soft switching) is used. At some magnitude of sample difference, the loss of resolution due to a double image is equal to the loss of resolution due to interpolation. That corporeality of motion should consequence in the crossfader beingness at the l% point. Less motion will result in a fade towards field merging and more motion in a fade towards the interpolated values.

Insider Info

Rather than "per pixel" motion adaptive deinterlacing, which makes decisions for every sample, some low-cost solutions use "per field" motility adaptive deinterlacing. In this case, the algorithm is selected each field, based on the amount of motion betwixt the fields. "Per pixel" motion adaptive deinterlacing, although difficult to implement, looks quite good when properly done. "Per field" motion adaptive deinterlacing rarely looks much meliorate than vertical interpolation.

Motion-Compensated Deinterlacing

Motility-compensated (or motion vector steered) deinterlacing is several orders of magnitude more complex than motion adaptive deinterlacing, and is commonly institute in pro-video format converters.

Move-compensated processing requires computing move vectors between fields for each sample, and interpolating along each sample'south motion trajectory. Motility vectors must also be found that laissez passer through each of whatsoever missing samples. Areas of the picture may be covered or uncovered as y'all move betwixt frames. The motion vectors must besides take sub-pixel accuracy, and exist determined in ii temporal directions between frames.

The motion vector errors used by MPEG are self-correcting since the residual divergence betwixt the predicted macroblocks is encoded. As motion-compensated deinterlacing is a single-ended organization, motion vector errors will produce artifacts, so different search and verification algorithms must exist used.

Read full chapter

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/B9780750689755000054

MPEG-iv, H.264/AVC, and MPEG-vii: New Standards for the Digital Video Manufacture

Berna Erol , ... Gary Sullivan , in Handbook of Image and Video Processing (Second Edition), 2005

3.2.1-7 Frame/Field Adaptive Coding.

H.264/AVC includes tools for efficiently handling the special backdrop of interlaced video, since the two fields that compose an interlaced frame are captured at unlike instances of time. In areas of high motion, this can lead to less statistical correlation betwixt adjacent rows within the frame, and greater correlation within individual fields, making field coding (where lines from only a single field compose a macroblock) a more efficient choice. In improver to regular frame coding in which lines from both fields are included in each macro-block, H.264/AVC provides two options for special handling of interlaced video: field picture coding and macroblock-adaptive field/frame coding (MB-AFF).

Field coding provides the option of coding pictures containing lines from just a single video field (i.due east., a picture composed of simply top field lines or only lesser field lines). Depending on the characteristics of the frame, an encoder tin can cull to code each input moving-picture show as two field pictures, or as a complete frame pic. In the case of field coding, an alternate zig-zag coefficient scan pattern is used, and private reference fields are selected for motion compensated prediction. Thus, frame/field adaptivity tin occur at the flick level. Field coding is virtually effective when there is significant motion throughout the video scene for interlaced input video, as in the case of camera panning.

On the other hand, in MB-AFF coding, the adaptivity betwixt frame and field coding occurs at a level known as the macroblock pair level. A macroblock pair consists of a region of the frame that has a height of 32 luma samples and width of xvi luma samples and contains two macroblocks. This coding method is nearly useful when there is meaning motion in some parts of an interlaced video frame and little or no move in other parts. For regions with little or no motion, frame coding is typically used for macroblock pairs. In this style, each macroblock consists of sixteen consecutive luma rows from the frame, thus lines from both fields are mixed in the same macroblock. In moving regions, field macroblock pair coding can be used to separate each macroblock pair into 2 macroblocks that each include rows from only a single field. Frame and field macroblock pairs are illustrated in Fig. 19. The unshaded rows compose the first (or top) macroblock in each pair, and the shaded rows compose the second (or bottom) macroblock. Effigy nineteen(a) shows a frame macro-cake pair, in which samples from both fields are combined in each coded macroblock. Figure 19(b) shows a field macro-block pair, in which all of the samples in each of the two macroblocks are derived from a unmarried field. With MB-AFF coding, the internal macroblock coding remains largely the same every bit in ordinary frame coding or field coding. However, the spatial relationships that are used for motility vector prediction and other context decision become significantly more complicated in lodge to handle the low-level switching between field and frame based operation.

Figure nineteen. Illustration of macroblock pairs.

Read full chapter

URL:

https://world wide web.sciencedirect.com/scientific discipline/commodity/pii/B9780121197926501133

Video coding standards and formats

David R. Bull , Fan Zhang , in Intelligent Prototype and Video Pinch (Second Edition), 2021

MPEG-4 part ii advanced elementary profile (ASP)

The Advanced Elementary profile was the well-nigh commonly used MPEG-four profile, offering support for interlaced video, B-pictures, quarter-pixel motion compensation, and global motion compensation. The quarter-pixel accuracy was after adopted in H.264/AVC whereas the global move bounty feature was non more often than not supported in well-nigh implementations. As the reader will find, ASP does non offer a lot that is not present in H.263; in fact the uptake of H.263 was far more than widespread than that of ASP.

Soon subsequently the introduction of ASP, MPEG-iv visual work refocused on part ten and this became a joint activity with ITU-T under the H.264/AVC banner. This major step forrad is the topic of the adjacent section.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780128203538000219

Digital Video Overview

Anthony C. Caputo , in Digital Video Surveillance and Security (2d Edition), 2014

Progressive Scanning

Digital encoders provide a deinterlacing filter, or a progressive scanning selection, to avoid the jaggedness from interlaced video (which is a throwback to the original analog video). Deinterlacing or progressive scan (see Figure ii.4) requires more than processing power and is specially important at the highest resolutions, since the distortion tin can be more easily recognized. All cameras with slower shutter speeds can create blurred images of motion. This is emphasized even more with interlaced distortion considering it is simply not fast enough to capture the motion.

FIGURE 2.four. Deinterlacing eliminates the jagged lines.

Progressive scan, as opposed to interlaced, scans the unabridged picture line past line, in sequential order, every sixteenth of a second, without segregating the scene into two separate fields. Digital applied science does not need interlaced scanning for video presentation. Digital video eliminates the "flickering" effect as long as the display monitor is also of suitable quality, and more important, the digital devices provide the capability for deinterlacing and/or progressive scanning.

Most DVD players now employ progressive browse at 480p, since the majority of homes have a standard boob tube set limited to the 480i resolution. If a DVD picture is displayed on HDTV, the DVD player can "upconvert" or "upsample" the 480p to the maximum resolution on the HDTV (eastward.yard., 1080i). Depending on the DVD player and HDTV, this can be an automated procedure or something that needs to be accomplished manually.

Therein lies the deviation betwixt viewing HDTV on a 1080i (interlaced scan) display versus a 1080p (progressive scan) display. Traditional analog goggle box has a maximum of 480 browse lines, which is the maximum output for analog video. Digital cable or satellite television offers high-definition 1080 progressive scan resolution, but just with HDTV. If HDTV, computer monitor (CRT or LCD), or projector is limited in color depth, resolution (less than 1080), and/or progressive scanning capabilities, it will then catechumen the 1080p into 1080 interlaced scan lines.

Read total chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780124200425000022

Motion-picture show Formats: Media, Resolution and Attribute Ratios

RON BRINKMANN , in The Art and Science of Digital Compositing (Second Edition), 2008

Converting and Combining Formats

We've tried to requite a very broad overview of the broad variety of formats that you may meet. Depending on your particular situation, you lot may never need to deal with nearly of these formats. On the other hand, you lot may notice yourself working on a composite in which you demand to combine several different formats at the same fourth dimension. Usually this doesn't present much of a problem, since the different images tin can simply exist scaled as needed. A mixture of squeezed and unsqueezed images will apparently require you to determine a working aspect ratio then to conform everything to that standard. In that location may even be times when you wish to combine film and video in the same image.

You may likewise exist required to output to several unlike formats every bit part of what you deliver. And this support for multiple formats is more than than only a file-format conversion. Consider the case where the dissimilar formats have significantly different aspect ratios—for instance if yous accept cloth that was shot in a 16:ix aspect ratio but needs to be displayed at an aspect ratio of 4:3. In this situation at that place is an artful decision to be made for how the imagery is converted. We more often than not cannot simply resize the first epitome to fit into the attribute ratio of the second since this would introduce an undesirable squeeze to the image.

Consider the paradigm shown in Figure 10.12. This is the full frame of the image that we looked at before, and information technology has an attribute ratio of 4:three. Creating wider aspect ratios of this epitome are easy enough—we tin can simply crop some area off the height or lesser. Figure x.13a shows a xvi:ix extraction from the original and Figure ten.13b shows a 2.35 extraction. (Both of these examples were extracted from the heart of the image, also known as eye extraction.) Already we can see that sure decisions need to exist made when converting from one aspect ratio to some other. We are obviously throwing away paradigm data and consequently the nature of the image changes. Peculiarly with the more extreme 2.35 extraction we accept produced an prototype that isn't nearly as well framed as the original. We could certainly cull a different extraction—Effigy ten.13c is also a 2.35 extraction but at least it keeps all the blades of the windmill in the frame and might thus be considered more acceptable.

Figure x.12. An original image with a 4:3 aspect ratio.

Effigy x.13a. A 16:nine extraction from Effigy 10.12.

Figure 10.13b. A two.35 extraction from Figure 10.12.

Figure ten.13c. A unlike 2.35 extraction, with better framing of the subject.

It gets even more than interesting if nosotros need to convert from a wider format to a more square one. If, for instance, nosotros had shot this image originally on High-Definition video it would look much like what we saw in Figure 10.13a—an epitome with a xvi:9 aspect ratio. If nosotros now want to convert it to a four:three format, we could crop information from the sides of the epitome instead, giving us something like we run across in Figure x.fourteen.

Effigy 10.14. A 4:three extraction from the 16:9 frame in Figure 10.13a.

But, again, this has caused a fairly significant alter to the image. It may non be especially problematic in an image such as this, only consider the scenario of a wide-screen prototype where two characters are speaking to each other while standing at either side of the frame. Cropping a less-broad aspect ratio image out of this source may very well remove one, or fifty-fifty both, of the characters—probably not what the director/cinematographer intended!

There is another method that can exist used instead, and it involves scaling the entire image down to fit into the frame nosotros need to work with and so padding the extra areas with blackness. This second method is typically known every bit letterboxing, and an instance of taking our 16:ix image and placing information technology into a 4:3 frame using this method is shown in Figure ten.15. All of the imagery from the original frame is there simply the picture is smaller and we now take blackness bars at the top and bottom.

Figure x.15. Letterboxing the 16:9 frame to produce an paradigm with a iv:3 aspect ratio.

Since this method, likewise, isn't always desirable there is actually a 3rd technique that comes into play. Known as pan and browse, this method creates an blithe ingather region that moves back and forth over the frame as appropriate. In the instance we're looking at, the crop might offset showing a 4:three crop from the left one-half of the image (shown in Effigy 10.16a) and, over a flow of time, volition motion to the framing shown in Effigy 10.16b. The success of this technique is extremely dependent on the nature of the original footage. When done well information technology can be nearly invisible, giving the impression that the original camera operator was moving the camera in such a style when the footage was originally shot. But many shots volition already have a camera movement that tin can disharmonize with whatsoever additional pan and browse or happen also speedily to be appropriate for such a process.

Effigy 10.16a. A pan-and-scan four:3 extraction from the 16:9 frame—kickoff frame.

Figure 10.16b. A pan-and-scan iv:3 extraction from the xvi:9 frame—end frame.

Given these issues, many films are intentionally shot with multiple commitment formats in mind. Framing will often be done a bit more "loose" (wider) then that there will exist more options when converting to a dissimilar format. For instance, oft a moving-picture show will be photographed with the intention to project in a widescreen format but the camera will actually capture additional (unimportant) image at the top or bottom or both. These extra areas will still need to be free from the typical lights, stands and cables plant on a film set and as such they are referred to as "protected" areas of the epitome. In many cases, animated films will even be rendered to the largest necessary format, allowing for eventual scaling and resizing into the various distribution formats.

Converting Between Moving-picture show and Video

Although this chapter gave a number of examples of how formats might exist converted throughout the compositing procedure, there is a particular conversion that bears further scrutiny: the film-to-video conversion and its reverse, video to film. This conversion is problematic primarily considering of the different frame rates that the formats in question utilise, particularly when converting between NTSC video at 30 fps and standard film at 24 fps.

In Chapter 7 we discussed some general-purpose methods for converting between dissimilar frame rates, but the specific conversion between film and interlaced video occurs often enough that a well-defined standard process has emerged. It involves taking a flick frame and converting it to two fields of video, and then taking the next film frame and converting it to three fields of video. This alternating cosmos of two and then three fields in social club to synchronize motion picture timing to video (NTSC) timing is known as a two:3 pulldown. 14 A diagram of this process is shown in Effigy 10.17.

Figure 10.17. The 2:3 pulldown conversion.

Film frame A is used to create both fields of our first video frame. Film frame B is used to create both fields of video frame 2, and also the get-go field of video frame iii. Film frame C is then used to create the second field of video frame 3, and also the first field of video frame four. Finally, film frame D is used to create the second field of video frame 4 as well as both fields of video frame 5. Equally you tin can run across, iv picture show frames volition brand up exactly 5 video frames, and thus 24 film frames will make up 30 video frames.

Converting between film at 24 fps and PAL video (25 fps) can exist washed in one of two means. The simplest method is to do a straight frame-for-frame transfer between the two, so that any given pic frame corresponds direct to a sure video frame. This volition obviously change the speed of whatsoever motility in the footage that is existence transferred, simply the speedup is but virtually 4% and is fairly subtle—subtle enough that the simplicity of the process makes it worthwhile. (Not to mention the fact that any movie that is transferred to video for television receiver broadcast will exist 4% shorter, giving more than room for commercials!) Only if a more accurate transfer is needed, a 25th video frame will need to be generated from the 24 film frames. Only duplicating one of the frames would exist visually noticeable, so instead two additional video fields are created, one from the 12th film frame and the other from the 24th.

These frame-rate conversions are usually accomplished by special telecine hardware that deals with both the digitization of the film and the pulldown. The procedure of going from video to film is much less common, but would follow the aforementioned logic for the speed alter, in this instance deinterlacing video fields in order to produce flick frames. For the case of NTSC to film, the process is known every bit a 2:3 pullup.

If picture is being shot with the sole intention of transferring it to video, then the motion-picture show camera can oftentimes just exist adapted to shoot at the advisable frame charge per unit, 30 fps or 25 fps, and whatsoever pulldown conversions tin therefore exist avoided. Many picture show cameras can actually be set to shoot at exactly 29.97 fps to perfectly friction match NTSC's charge per unit.

Although the utilize of pulldown and pullup techniques to catechumen between frame rates is even so adequately common, it is speedily being displaced by more sophisticated methods that apply optical flow technologies. As mentioned in Chapter 7, these tools can analyze the motion of all pixels in an image and create intermediate frames based on selective warping. The same sort of algorithms can likewise exist extended to deal with field-to-frame conversions in a much meliorate fashion.

Read full affiliate

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/B9780123706386000109

From MPEG to H.264 Video Compression

Suhel Dhanani , Michael Parker , in Digital Video Processing for Engineers, 2013

fifteen.1.i.3 MPEG-2 Frame and Field DCT

MPEG-ane uses a frame-type DCT; that is the DCT is performed on 8   × eight arrays of pixels in the same frame. This would be sub-optimal when using interlaced video, equally differences betwixt the interlaced pixel rows in the frame could innovate substantial high-frequency content into the DCT coefficients, leading to poor compression.

MPEG-ii has an option to apply field DCT. When using field DCT, each of the four 8   ×   eight blocks in the 16   ×   xvi macrocell array has the DCT performed independently, resulting in four DCT coefficient arrays of viii   ×   viii each. For interlaced video, the sixteen   ×   xvi macrocell is divided into two 8 broad by 16 tall pixel arrays. An 8   ×   eight DCT transform is performed on the odd rows (ane, 3, five, 7) of each viii   ×   8 pixel array. This results in the acme array of viii   ×   viii DCT coefficients. A second eight   ×   viii DCT transform is then performed on the even rows (2, iv, six, 8) of each 8   ×   8 pixel assortment, and is used to compute the bottom array of eight   ×   8 DCT coefficients.

In this way, the interlaced sets of rows, which correspond to the two different instants in time of the video frame, are transformed and quantized separately.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780124157606000155

Raster scanning

In Digital Video and HD (Second Edition), 2012

Interlaced format

To refer to fields as odd and even invites confusion. Apply first field and second field instead. Some people refer to scanning first the odd lines and so the fifty-fifty; however, scan lines in interlaced video were historically numbered in temporal order, not spatial order: Scan lines are not numbered equally if they were rows in the frame'southward image matrix. Confusion on this betoken amid reckoner engineers – and confusion regarding tiptop and bottom fields – has led to lots of improperly encoded video where the summit and bottom offsets are wrong.

Interlacing is a scheme which – for given viewing distance, flicker sensitivity, and data rate – offered some increase in static spatial resolution over progressive scanning in historical CRT displays, which exhibited flicker. The total height of the image is scanned leaving gaps in the vertical management. Then, i/50 or ane/60 southward afterward, the full image tiptop is scanned again, but offset vertically so as to fill in the gaps. A frame thereby comprises ii fields, denoted first and 2d. The scanning machinery is depicted in Figure 8.5. Historically, the same scanning standard was used across an entire television receiver arrangement, so interlace was used not merely for display merely for the whole chain, including conquering,recording, processing, distribution, and transmission.

Effigy 8.5. Interlaced format represents a complete picture -the frame – from two fields, each containing one-half of the total number of prototype rows. The 2nd field is delayed past half the frame time from the first. This example shows x paradigm rows. In analog scanning, interlace is effected by having an odd number of full scan lines (e.,g., 525, 625, or 1125).

Noninterlaced (progressive) scanning is universal in desktop computers and in calculating; also, progressive scanning has been introduced for digital television and Hard disk. However, the interlace technique remains universal in SD, and is widely used in circulate HD. Interlace-to-progressive (I-P) conversion, also called deinterlacing, is an unfortunate but necessary by-production of interlaced scanning.

CRTs are now obsolete. The dominant display technologies now used for video – LCD and plasma panels have relatively long duty cycles, and they don't flicker. The raison d'être for interlace has vanished. Nonetheless, interlace remains in wide use.

Read full chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9780123919267500084

Metadata

In Digital Video and HD (Second Edition), 2012

Metadata Instance 2: .yuv files

The ".yuv" file format was introduced by Abekas in the late 1980s to shop uncompressed video. Given samples of viii-bit Y′C B C R , 4:ii:ii interlaced video in raster order, the file format definition is essentially as follows:

Shop successive image rows, where each row is a sequence of 4-byte elements [C B0, Y 0 ′, C R0, Y 1 ′] where subscript 0 signifies an fifty-fifty-numbered luma sample location and subscript 1 signifies odd.

In that location is no header in a .yuv file – in particular, there is no provision for storing the count of frames, image rows, or prototype columns. The format was introduced to store 720 ×480 video. Afterward, it was practical to 720 ×576. It could potentially exist applied to 720 ×481, 720×483, 720×486, or 704 ×480. It has been used in the codec inquiry community for 1280×720p and 1920 ×1080 i.

Consider the reading of .yuv files constrained to be 720×480 or 720 ×576. Most of the time the format tin exist determined by dividing the file's bytecount by 1440, then dividing by 480 and 576 in turn to run across which quotient is an integer. But that approach doesn't always work. For instance, a iv,147,200-byte file could be six frames of 480i or five frames of 576 i.

Reliable file interpretation is attained but by agreement between sender and receiver – or expressed more properly in terms of files, betwixt writer and reader – that is, outside the scope of transfer of the file itself.

Imagine extending the .yuv file format past prepending a file header comprising three 32-bit words: a count of the number of frames, a count of the number of paradigm rows, and a count of the number of image columns. Is the header data or metadata? If your "system" is defined in advance every bit being 480 i, and then the counts in the header are inessential, auxiliary information – telephone call information technology metadata. Only if your "arrangement" is multiformat, so the counts are nigh certainly data, because reliable estimation of the image portion of the file is incommunicable without the numbers in the header.

The conclusion is this: What comprises "metadata" depends upon what yous consider to be your "system." The larger, more than inclusive, and more general your system – the less you lot depend upon context – the more than your metadata turns into information.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780123919267500187

Avant-garde Video Coding: Principles and Techniques

King Northward. Ngan , ... Douglas Chai , in Advances in Image Advice, 1999

Half Sample Search

Half sample search is performed using the previous reconstructed VOP on the luminance component of the macroblock, for 16   ×   sixteen and 8   ×   8 vectors as well as for 16   × 8 field motion vectors in the instance of interlaced video. The search surface area is ±  1 half sample effectually the region pointed to past the move vectors V0, V1, V2, V3, V4 or the field motion vector (fxp,q, fyp,q ). The half sample values are calculated by bilinear interpolation horizontally and vertically as shown in Fig. half-dozen.17 below:

Effigy 6.17. Bilinear interpolation scheme. ©ISO/IEC 1998

The vector resulting in the best match during the half sample search is named MV. MV consists of horizontal and vertical components (MVten, MVy ), both measured in one-half sample units.

For interlaced video, the half sample search used to refine the field motion vectors is conducted by vertically interpolating between lines of the aforementioned field. The field movement vectors are calculated in frame coordinates; that is the vertical coordinates of the integer samples differ by two.

Read full chapter

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/S0928147999800084