Editing MPEG-1 Audio Layer II (section)

=== Live broadcasts ===
MPEG-1 Audio Layer II is the audio format used in [[Digital Audio Broadcast]] (DAB), a [[digital radio]] [[international standard|standard]] for [[broadcasting]] [[digital audio radio service]]s that has been adopted in many regions around the world. The [[BBC]] Research & Development department states that at least 192&nbsp;kbit/s is necessary for a [[high fidelity]] stereo broadcast:{{blockquote|A value of 256&nbsp;kbit/s has been judged to provide a high quality stereo broadcast signal. However, a small reduction, to 224&nbsp;kbit/s is often adequate, and in some cases it may be possible to accept a further reduction to 192&nbsp;kbit/s, especially if redundancy in the stereo signal is exploited by a process of 'joint stereo' encoding (i.e. some sounds appearing at the centre of the stereo image need not be sent twice). At 192&nbsp;kbit/s, it is relatively easy to hear imperfections in critical audio material.|BBC R&D White Paper WHP 061 June 2003<ref name=":1">{{cite web |url=http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP061.pdf |title=BBC R&D White Paper WHP 061 June 2003, DAB:An introduction to the EUREKA DAB System and a guide to how it works |publisher=BBC.co.uk |access-date=2007-05-08 |archive-date=2009-03-04 |archive-url=https://web.archive.org/web/20090304001258/http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP061.pdf |url-status=live }}</ref>}}

As of 2025, MPEG-1 Audio Layer II remains in widespread use in the United Kingdom for DAB broadcasts; the newer DAB+ standard which is now predominant elsewhere in Europe and in other regions does not use MP2 but [[HE-AAC]] instead.<ref>http://www.frequencyfinder.org.uk/Introduction_to_DAB.pdf</ref> MP2 was also adopted as the audio format used by [[Astra Digital Radio]] (ADR) broadcasts and by the [[Multimedia Home Platform]] (DVB-MHP) standard for set-top boxes. MP2 is also used alongside [[Dolby Digital|Dolby Digital (AC3)]] in the audio streams for some [[DVB]] broadcasts.<ref>{{Cite web |title=DVB · carfax |url=https://www.carfax.org.uk/docs/8/ |access-date=2025-04-17 |website=www.carfax.org.uk}}</ref>

MPEG-1 Audio Layer II is commonly used{{Update inline|date=April 2025}} within the broadcast industry for distributing live audio over satellite, ISDN and IP Network connections as well as for storage of audio in digital playout systems. An example is [[NPR]]'s [[Public Radio Satellite System|PRSS]] Content Depot programming distribution system. The Content Depot distributes MPEG-1 L2 audio in a Broadcast Wave File wrapper. MPEG2 with RIFF headers (used in <code>.wav</code>) is specified in the RIFF/WAV standards. As a result, Windows Media Player will directly play Content Depot files, however, less intelligent <code>.wav</code> players often do not. As the encoding and decoding process would have been a significant drain on CPU resources in the first generations of broadcast playout systems, professional broadcast playout systems typically implement the codec in hardware, such as by delegating the task of encoding and decoding to a compatible soundcard rather than the system CPU.