Skill Area 214: Use a Multimedia Application (SWA)
Skill Area 214: Use a Multimedia 214.4 Produce Audio Files
What is digital audio? Audio is another meaning for sound. Digital audio refers to a digital representation of the audio waveform for processing, storage or transmission in digital format.
Audio in Multimedia To enhance graphics, images, text, narrations, voiceovers etc. Consequently, the power of communication and interactivity via the audio interface will bring us an even closer relationship with the computer. It is the result of interactions between images, music, the spoken text, sound effects etc.
Audio in Multimedia Good audiovisual is therefore a language of synthesis. (Ferrés P., Joan.1998:118) A good synthesis, where the expressive elements interact well, are demonstrated by the fact that the receiver has a unified experience. (Ferrés P., Joan.1998:118)
How does it work? Digital recording and reproduction converts the analog sound signal picked up by the microphone to a digital form by a process of digitization, allowing it to be stored and transmitted by a wider variety of media. Digital recording stores audio as a series of binary numbers representing samples of the amplitude of the audio signal at equal time intervals, at a sample rate high enough to convey all sounds capable of being heard.
How does it work? Digital recordings are considered higher quality than analog recordings not necessarily because they have higher fidelity (wider frequency response or dynamic range), but because the digital format can prevent much loss of quality found in analog recording due to noise and electromagnetic interference in playback, and mechanical deterioration or damage to the storage medium.
How does it work? A digital audio signal must be reconverted to analog form during playback before it is applied to a loudspeaker or earphones.
How does it work? Analog Signal Digital Signal Analog Signal Converter Converter microphone RECORD PROCESS (CONVERSION) Radio PLAYBACK
Audio Format Audio Formats can be broken down into three main categories: 1. Uncompressed format 2. Lossless compression format 3. Lossy compression format
Uncompressed Format Often referred to as PCM formats Formats that use no compression. This means all the data is available, at the risk of large file sizes. A WAV audio file is an example of an uncompressed audio file.
Loseless Compression Format Applies compression to an uncompressed audio file. It does not lose information or degrade the quality of the digital audio file. The WMA audio file format uses lossless compression.
Lossy Compression Format Results in some loss of data as the compression algorithm eliminates redundant or unnecessary information. However, lossy compression has become popular online because of its small file size. It is easier to transmit over the Internet. MP3 and Real Audio files uses a lossy compression.
Audio Format Types Uncompressed format Loseless Compression Format WAV FLAC MP3 AIFF Monkey's Audio (APE) Vorbis AU WavPack (WV) Musepack PCM TTA AAC ATRAC Advanced Lossless Lossy Compression Format ATRAC Apple Lossless (m4a) MPEG Windows Media Audio Lossless (WMA Lossless) Windows Media Audio Lossy (WMA lossy) Shorten (SHN)
Windows Compatible Audio MP3 (.mp3) MP3 is the name of the file extension and also the name of the type of file for MPEG audio layer 3. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 removes all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal). The result in real terms is layer 3 shrinks the original sound data from a CD (with a bit rate of 1411.2 kilobits per one second of stereo music) by a factor of 12 (down to 112-128kbps) without sacrificing sound quality. Format
Windows Compatible Audio Format WMA - Windows Media Audio (.wma) Short for Windows Media Audio, WMA. A Microsoft file format for encoding digital audio files similar to MP3 though can compress files at a higher rate than MP3. WMA files, which use the.wma file extension, can be of any size compressed to match many different connection speeds, or bandwidths.
Windows Compatible Audio WAV (.wav) Format WAV is the format used for storing sound in files developed jointly by Microsoft and IBM. It is a de facto standard for sound on PCs. WAV sound files end with a.wav extension and can be played by nearly all Windows applications that support sound.
Windows Compatible Audio Format Real Audio (.ra.ram.rm) Real Audio is a proprietary format, and is used for streaming audio that enables you to play digital audio files in real-time. To use this type of file you must have RealPlayer (for Windows or Mac), which you can download for free. Real Audio was developed by RealNetworks.
Windows Compatible Audio Format MIDI - Musical Instrument Digital Interface (.mid) Short for musical instrument digital interface. MIDI is a standard adopted by the electronic music industry for controlling devices, such as synthesizers and sound cards, that emit music. At minimum, a MIDI representation of a sound includes values for the note's pitch, length, and volume. It can also include additional characteristics, such as attack and delay time.
Windows Compatible Audio Ogg (.ogg) Format Ogg is an audio compression format, comparable to other formats used to store and play digital music, Differs in that it is free, open and unpatented. It uses Vorbis, a specific audio compression scheme that's designed to be contained in Ogg.
Microphone Audio recording & editing software Speaker Monitor Mouse Basic requirements for audio Sound card Audio mixer (optional) recording setup Earphones or headset (optional)
Audio recording applications Audio MP3 Sound Recorder Easy MP3 Recorder Audacity Nero Wave Editor 4 Macromedia Sound Edit
Summary Digital audio refers to a digital representation of the audio waveform for processing, storage or transmission in digital format Audio can be converted from analog signal to digital signal and vice versa There are 3 kinds of audio format: uncompressed format, lossless compression format, lossy compression format There are specific equipment requirements that is necessary to an audio recording setup An audio recording/editing application is necessary to produce an audio file
Thank You!