computer science

RF64

RF64 is a computer 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 RF64 rather than just read about it. In short: RF64 is a BWF-compatible multichannel audio file format enabling file sizes to exceed 4 GiB. It has been specified by the European Broadcasting Union.

Key takeaways

RF64 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RF64 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RF64 from memory before moving on to harder problems.

Reference excerpt

RF64 is a BWF-compatible multichannel audio file format enabling file sizes to exceed 4 GiB. It has been specified by the European Broadcasting Union. The file format is designed to meet the requirements for multichannel sound in broadcasting and audio archiving. It is based on the Microsoft RIFF/WAVE format and Wave Format Extensible for multichannel parameters. Additions are made to the basic specification to allow for more than 4 GB file sizes when needed (the new maximum filesize is now approximately 16 exabytes). The format is transparent to the BWF and all its supplements and chunks. RF64 WAV files typically use the .wav file extension. RF64 is the basis for ITU recommendation ITU-R BS.2088, which defines a substantially similar standard, BW64, which replaces binary format metadata chunks with extensible XML metadata. EBU Tech 3306 Version 2 (2018) now recommends the use of BW64 format exclusively, to avoid duplication of standards.

Capability RF64 specifies a maximum of 18 surround channels, stereo down mix channel and bit stream signals with non-PCM coded data can also be stored in the file format. RF64 can be used in the entire programme chain from capture to editing and play out and for short or long term archiving of multichannel files. Due to the inconsistent usage of CUE data definition, the additional requirement that CUE chunk names be stored in an additional LABL chunk, along with the inherent 32-bit limitation of the CUE chunk pointer index, the 2009 RF64 format also defines a new 'r64m' marker chunk.

Format In its basic form, the 32-bit chunk size field at offset 4 in the file is set to -1 (0xFFFFFFFF), and immediately following that a new 'ds64' chunk is inserted (before the FMT chunk). This new ds64 chunk will contain the 64-bit sizes of the DATA chunk(s), using a simple sequential table mechanism to point to additional DATA chunks. The first 4 bytes of the file are then changed from 'RIFF' to 'RF64'. RF64 files define the following extra chunks:

"RF64" replaces "RIFF" chunk identifier of BWF/WAV formats ds64, data size 64, first chunk under RF64 JUNK, a placeholder for ds64 An RF64 file with a 'bext' chunk becomes an MBWF-file. 'bext' is defined in BWF (ITU-R BS.1352-3). ITU-R BS.2088, BW64 is mostly compatible with RF64, with the following changes:

"BW64" replaces "RF64" chunk identifier axml, from BWF bxml, like "axml" in BWF (ITU-R BS.1352-3), but compressed sxml, sound-related XML data chna, channel info The replacement of bext and ubxt chunks with XML metadata.

Worked examples

Example 1 — a first encounter with RF64

Start with the simplest possible case. Write down what RF64 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer 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 RF64 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 RF64 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 RF64

In research: RF64 appears in computer 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 RF64 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: RF64 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer file formats, Digital audio, so understanding it makes those chapters shorter.
In everyday life: Look for RF64 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 RF64 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RF64 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 RF64 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RF64 in simple terms?

RF64 is a BWF-compatible multichannel audio file format enabling file sizes to exceed 4 GiB. It has been specified by the European Broadcasting Union.

Why does RF64 matter?

Because it connects several computer 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 RF64?

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 RF64.