science

HDV

HDV is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand HDV rather than just read about it. In short: HDV is a format for recording of high-definition video on DV videocassette tape. Conceived as an affordable high definition format for digital camcorders, HDV quickly caught on with many amateur and professional videographers due to its low cost, portability, and image quality acceptable for many professional productions.

Key takeaways

HDV belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HDV to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HDV from memory before moving on to harder problems.

Reference excerpt

HDV is a format for recording of high-definition video on DV videocassette tape. Conceived as an affordable high definition format for digital camcorders, HDV quickly caught on with many amateur and professional videographers due to its low cost, portability, and image quality acceptable for many professional productions. The format was marketed mainly in the mid and late 2000s. HDV and the HDV logo are trademarks of JVC and Sony.

History The format was originally developed by JVC and supported by Sony, Canon, and Sharp. The four companies formed the HDV Consortium in September 2003. JVC released its latest HDV camcorder — the GY-HD250 — in 2006. In September 2011 this model was discontinued on the U.S. market. The "B" modification of the older GY-HD200 was released in 2008 and discontinued in November 2009. The latest HDV camcorder made by Canon — the HV40 — was released in 2009, but it traces back to the HV20 developed in 2007, and was phased out of production during 2011, though stocks have lasted through 2012. The latest Sony consumer HDV model is the HDR-HC9, originally released in 2008 and discontinued on the North American market in 2011. 2008 was also the year when Sony presented the latest "advanced amateur" and professional HDV camcorders, namely the HDR-FX1000 and the HVR-Z5. All the three major manufacturers of HDV equipment — JVC, Canon and Sony — heavily invested in development of MPEG-2 video compression scheme and continued to rely on it in their professional tapeless camcorder lineups: XDCAM HD (Sony), XDCAM EX (Sony and JVC), XDCAM HD422 (Sony), XF Codec (Canon). At the same time Sony, Canon and later JVC joined Panasonic in marketing of AVCHD recording format, which is claimed to deliver visual quality similar to HDV at half the datarate. Consumer high definition camcorders released by these companies since 2009 employ AVCHD format. In 2010 industry analysts did not expect new HDV products, but believed that manufacturers would continue to support HDV for their existing users, while at the same time transitioning to file-based workflow. When accessed in 2017, the Broadcast & Production Cameras section on Sony's website does not mention HDV technology. The HDV page does not list any equipment or whitepapers.

Video and audio coding

HDV video and audio are encoded in digital form, using lossy inter frame compression. Video is encoded with the H.262/MPEG-2 Part 2 compression scheme, using 8-bit chroma and luma samples with 4:2:0 chroma subsampling. Stereo audio is encoded with the MPEG-1 Layer 2 compression scheme. The compressed audio and video are multiplexed into an MPEG-2 transport stream, which is typically recorded onto magnetic tape, but can also be stored in a computer file. The data rate for both the audio and video is constant and is roughly the same as DV data rate. The relatively low video data rate can cause bit rate starvation in scenes that have much fine detail, rapid movement or other complex activity like flashing lights, and may result in visible artifacts, such as blockiness and blurring. In contrast to the video, HDV audio bitrate is relatively generous. At the coded bitrate of 384 kbit/s, MPEG-1 Layer 2 audio is regarded as perceptually lossless.

Recording formats Two major versions of HDV are HDV 720p and HDV 1080i. The former is used by JVC and is informally known as HDV1. The latter is preferred by Sony and Canon and is sometimes referred to as HDV2. The HDV 1080i defines optional progressive recording modes, and in recent publications is sometimes called HDV 1080 or 1080-line HDV as progressive 1080-line recording becomes commonplace.

HDV 720p HDV 720p format allows recording high definition video (HDV-HD) as well as progressive-scan standard definition video (HDV-SD). HDV-HD closely matches broadcast 720p progressive scan video standard in terms of scanning type, frame size, aspect ratio and data rate. Earlier HDV 720p camcorders could shoot only at 24, 25 and 30 frames per second. Later models offer both film-like (24p, 25p, 30p) and reality-like (50p, 60p) frame rates. HDV-SD is a mode for recording progressive-scan standard definition video. Such a video is sometimes called enhanced definition video (EDTV), but is considered high definition video in Australia. Depending on region, HDV-SD video is recorded either as 576p50 or as 480p60. Like DVCPRO Progressive, HDV-SD was meant as an intermediate format during the transition time from standard definition to high definition video. Later models of HDV 720p camcorders do not record in this mode. JVC was the only manufacturer of HDV 720p camcorders. JVC was the first to release an HDV camcorder, the handheld GR-HD1. Later JVC shifted its HDV development to shoulder-mounted cameras. A common misconception is that JVC developed a proprietary extension to HDV called ProHD, featuring film-like 24-frame/s progressive recording mode and LPCM audio, for professional use. JVC has clarified that ProHD is not a video recording format, but "an approach for delivering affordable HD products" and a common name for "bandwidth efficient professional HD models".

HDV 1080i

… excerpt ends here. Continue reading the full article.

Illustrations

HDV: When interlaced video is watched on a progressive monitor without proper deinterlacing, it exhibits combing when there is movement between two fields of one frame. — When interlaced video is watched on a progressive monitor without proper deinterlacing, it exhibits combing when there is movement between two fields of one frame.

Native Progressive logo (Canon)

Worked examples

Example 1 — a first encounter with HDV

Start with the simplest possible case. Write down what HDV claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to HDV before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about HDV ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of HDV

In research: HDV appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses HDV in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: HDV is common in secondary-school and first-year university syllabi. It links to neighbouring topics Television terminology, Video storage, so understanding it makes those chapters shorter.
In everyday life: Look for HDV outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study HDV in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HDV means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain HDV out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HDV in simple terms?

Why does HDV matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study HDV?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on HDV.

HDV