science

G.719

G.719 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 G.719 rather than just read about it. In short: G.719 is an ITU-T standard audio coding format providing high quality, moderate bit rate (32 to 128 kbit/s) wideband (20 Hz - 20 kHz audio bandwidth, 48 kHz audio sample rate) audio coding at low computational load. It was produced through a collaboration between Polycom and Ericsson.

Key takeaways

G.719 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect G.719 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of G.719 from memory before moving on to harder problems.

Reference excerpt

G.719 is an ITU-T standard audio coding format providing high quality, moderate bit rate (32 to 128 kbit/s) wideband (20 Hz - 20 kHz audio bandwidth, 48 kHz audio sample rate) audio coding at low computational load. It was produced through a collaboration between Polycom and Ericsson. G.719 is based on modified discrete cosine transform (MDCT) coding. It incorporates elements of Polycom's Siren22 codec (22 kHz) and Ericsson codec technology, as well as Polycom's Siren7 and Siren14 codecs (G.722.1 and G.722.1 Annex C), which have been used in videoconferencing systems for many years. As ITU-T Recommendation G.719, it was approved on June 13, 2008. G.719 is optimized for both speech and music. It is based on transform coding with adaptive time-resolution, adaptive bit-allocation and low complexity lattice vector quantization. The computational complexity is quite low (18 floating-point MIPS) for an efficient high-quality compressor. The codec operates on 20 ms frames, and the algorithmic delay end-to-end is 40 ms. The encoder input and decoder output are sampled at 48 kHz. In addition to the nominal bit rates of 32, 48 and 64 kbit/s, the G.719 codec has an inherent feature of flexible rate selection. In fact, it is possible to accommodate any rate between 32 kbit/s and 64 kbit/s by steps of 4 kbit/s. Moreover, the codec can also provide higher rates than 64 kbit/s and up to 128 kbit/s. Amendment 1 of the ITU-T G.719 specification defined the use of the ISO base media file format (ISO/IEC 14496-12 a.k.a. MPEG-4 Part 12) as container for the G.719 bitstream. It also defined stereo and multichannel use of G.719 bitstreams in the ISO base media file format. It addresses non-conversational use cases of the codec (e.g. call waiting music playback and recording of teleconferencing sessions, voice mail messages). Thus, media file formats such as MP4 (audio/mp4 or video/mp4) and 3GP (audio/3GPP and video/3GPP) can contain G.719-encoded audio. RFC 5404 defined media type audio/G719.

Licensing G.719 is licensed by Polycom, Inc. and by Ericsson; both licenses are necessary for use. Polycom licensees also receive the right to use G.722.1 (Siren7, Polycom's 7 kHz codec), and G.722.1 Annex C (Siren14, the 14 kHz equivalent).

See also Comparison of audio formats List of codecs

References

External links Official ITU-T G.719 standard RFC 5404 - RTP Payload Format for G.719

Worked examples

Example 1 — a first encounter with G.719

Start with the simplest possible case. Write down what G.719 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 G.719 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 G.719 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 G.719

In research: G.719 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 G.719 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: G.719 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audio codecs, ITU-T G Series Recommendations, ITU-T recommendations, so understanding it makes those chapters shorter.
In everyday life: Look for G.719 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 G.719 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what G.719 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 G.719 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is G.719 in simple terms?

Why does G.719 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 G.719?

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 G.719.