science

Time shifting

Time shifting 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 Time shifting rather than just read about it. In short: In broadcasting, time shifting is the recording of programming to a storage medium to be viewed or listened to after the live broadcasting. Typically, this refers to TV programming but it can also refer to radio shows via podcasts.

Key takeaways

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

Reference excerpt

In broadcasting, time shifting is the recording of programming to a storage medium to be viewed or listened to after the live broadcasting. Typically, this refers to TV programming but it can also refer to radio shows via podcasts. In recent years, the advent of the digital video recorder (DVR) has made time shifting easier, by using an electronic program guide (EPG) and recording shows onto a hard disk. Some DVRs have other possible time-shifting methods, such as being able to start watching the recorded show from the beginning even if the recording is not yet complete. In the past, time shifting was done with a video cassette recorder (VCR) and its timer function, in which the VCR tunes into the appropriate station and records the show onto video tape. Certain broadcasters transmit timeshifted versions of their channels, usually carrying programming from one hour in the past, to enable those without recording abilities to resolve conflicts and those with recording abilities more flexibility in scheduling conflicting recordings. (See timeshift channel.)

In the United Kingdom and Ireland Freesat+, Freeview+, Sky+, V+, TiVo, YouView and BT Vision services in Ireland and the UK allow one to timeshift.

Africa DStv, based in South Africa, offers PVR set-top boxes to countries across Africa which allow time shifting of live and recorded television, using a remote.

History in the United States The idea of a consumer pausing a live television broadcast was depicted in popular media as early as November 1966 at the end of Season 2, Episode 12 of I Dream of Jeannie, when character Major Nelson asked his genie to pause a live broadcast of a football game so that they could continue to watch it from that point after a grocery shopping trip. With the advent of digital video recorders ReplayTV and TiVo, launched at the 1999 Consumer Electronics Show in Las Vegas, Nevada, it became possible in practice for consumers to purchase devices that supported pausing live television broadcasts and "chase play" (playing back a delayed version of a recorded live stream while simultaneously continuing to record the live stream). The major legal issue involved in time shifting concerns "fair use" law and the possibility of copyright infringement. This legal issue was first raised in the landmark court case of Sony Corp. of America v. Universal City Studios, Inc. or the "Betamax case". In the 1970s, Universal and Disney sued Sony, claiming its timed recording capability amounted to copyright infringement. The Supreme Court of the United States found in favor of Sony; the majority decision held that time shifting was a fair use, represented no substantial harm to the copyright holder and would not contribute to a diminished marketplace for its product. RCA mentioned time shifting in its marketing as a reason to buy VCRs, even while an on-screen disclaimer mentioned the Betamax case and cautioned that "Such recordings should not be made". By 1985 cable movie channels encouraged time shifting by broadcasting films subscribers wanted for their home libraries overnight, so their VCRs could record them while they slept. Some providers, such as satellite TV companies, have introduced digital video recorder (DVR) features, thereby allowing consumers to skip over advertising entirely when watching a program which has been recorded to their DVR. The legality of this service, for which an extra fee can be assessed, has been challenged by television broadcasters, who assert that this form of time shifting is a violation of their copyright.

Analysis A study published in 2019 found that time shifting does not affect the size of the audience for a program which watches it live. Time shifting did, however, increase the size of the overall viewership of a program.

See also Timeshift channel Effects of time zones on North American broadcasting Space shifting (also known as place shifting) Format shifting Personal video recorder

References

External links

Recording for the purposes of time-shifting – UK Statutory Instrument 2003 No. 2498

Worked examples

Example 1 — a first encounter with Time shifting

Start with the simplest possible case. Write down what Time shifting 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 Time shifting 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 Time shifting 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 Time shifting

In research: Time shifting 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 Time shifting 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: Time shifting is common in secondary-school and first-year university syllabi. It links to neighbouring topics Copyright law, Digital rights, Digital television, so understanding it makes those chapters shorter.
In everyday life: Look for Time shifting 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 Time shifting in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Time shifting 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 Time shifting out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Time shifting in simple terms?

Why does Time shifting 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 Time shifting?

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 Time shifting.