solve below. the 600-Hz to 6000-Hz range and is produced by a…
Question Answered step-by-step solve below. the 600-Hz to 6000-Hz range and is produced by a… solve below. the 600-Hz to 6000-Hz range and is produced by a mechanical process that depends on the speaker’s vocal tract, tongue, and jaw. Some vocoders make use ofmodels of the vocal system to reduce speech to a few parameters (e.g., the sizesand shapes of various cavities) and a data rate of as little as 2.4 kbps. How thesevocoders work is beyond the scope of this book, however.We will concentrate on audio as sent over the Internet, which is typicallycloser to CD-quality. It is also desirable to reduce the data rates for this kind ofaudio. At 1.411 Mbps, stereo audio would tie up many broadband links, leavingless room for video and other Web traffic. Its data rate with compression can bereduced by an order of magnitude with little to no perceived loss of quality.Compression and decompression require signal processing. Fortunately, digitized sound and movies can be easily processed by computers in software. In fact,dozens of programs exist to let users record, display, edit, mix, and store mediafrom multiple sources. This has led to large amounts of music and movies beingavailable on the Internetnot all of it legalwhich has resulted in numerous lawsuits from the artists and copyright owners.Many audio compression algorithms have been developed. Probably the mostpopular formats are MP3 (MPEG audio layer 3) and AAC (Advanced AudioCoding) as carried in MP4 (MPEG-4) files. To avoid confusion, note thatMPEG provides audio and video compression. MP3 refers to the audio compression portion (part 3) of the MPEG-1 standard, not the third version of MPEG. Infact, no third version of MPEG was released, only MPEG-1, MPEG-2, andMPEG-4. AAC is the successor to MP3 and the default audio encoding used inMPEG-4. MPEG-2 allows both MP3 and AAC audio. Is that clear now? The nicething about standards is that there are so many to choose from. And if you do notlike any of them, just wait a year or two.Audio compression can be done in two ways. In waveform coding, the signal is transformed mathematically by a Fourier transform into its frequency components. In Chap. 2, we showed an example function of time and its Fourier amplitudes in Fig. 2-1(a). The amplitude of each component is then encoded in aminimal way. The goal is to reproduce the waveform fairly accurately at theother end in as few bits as possible.The other way, perceptual coding, exploits certain flaws in the human auditory system to encode a signal in such a way that it sounds the same to a humanlistener, even if it looks quite different on an oscilloscope. Perceptual coding isbased on the science of psychoacousticshow people perceive sound. BothMP3 and AAC are based on perceptual coding.The key property of perceptual coding is that some sounds can mask othersounds. Imagine you are broadcasting a live flute concert on a warm summer day.Then all of a sudden, out of the blue, a crew of workmen nearby turn on theirjackhammers and start tearing up the street. No one can hear the flute any more.Its sounds have been masked by the jackhammers. For transmission purposes, itis now sufficient to encode just the frequency band used by the jackhammersImage transcription textMatching a. source code b. integer C. compiler d. validation e. .computer programmer 26. collection of computer instructionswritten using a human-readable programming langua… Show more… Show moreImage transcription text10. Consider the following twomachine designs with their respectiveCPIs for various instructi… Show more… Show moreImage transcription textWe Create Inc. is an electronicscompany. It designs, produces, andassembles desktop gadg… Show more… Show more Computer Science Engineering & Technology Java Programming COMPUTER computer Share QuestionEmailCopy link Comments (0)
