- Audio role in Multimedia
- Attracts your attention/shocks/excites
- Change moods
- Feeling as you are in dream
- Give pleasure
- Inform
- Inform with style and impact
2. Audio is applied to
- Narration
- Dialogs, Conversation
- Background music
- Music mixed with narration
- Transition effects in audio
- Noise
- Real/Informative sounds
3. Selection of audio for multimedia
- Topic of multimedia presentation
- Sound related to information
- Objective of presentation
- Desire effect for presentation
- Target Audience
4. Factors which affects quality of recording
- Breathing
- Air conditioner noise
- Movement
- Suitability of recording settings
- Input volume level
- Consistency of settings
- Quality of source audio
- Quality and connectivity of cables
5. Sound Card
- 8bit, 16bit, 32bit
6. Layout of sound card
- Microphone connector
- Line in Jack
- Microphone in Jack
- Speaker out/Line out Jack
- Joystick/MIDI connector
- IDE connector
1.      Audio File formats (mentioning only few)
- AU files: (.au) are the most commonly used format format for cross-platform applications (the µ-law format, is also called AU from the file extension used for these files)
- AIFF files: Audio Interchange file format files (.aiff, .aif, and .aifc) are widely used on Macintosh and silicon graphics computers
- WAV files: WAV files(.wav) are used with Microsoft Windows applications
- MP3 files: By eliminating portions of the audio file that are essentially inaudible, mp3 files are compressed roughly one-tenth of audio formats such as WAV(uncompressed)etc.
- WMA files: Window Media Audio
- RA files: Real audio file format designed for streaming audio over the internet
- RIFF files: Resource Interchange File Format. Developed by Micorsoft
- SND/Sound files : This file format was developed by Apple and is l, imited to a sampling rate of 8bits
- MID/MIDI/MFF files: Musical Instrument Digital Interface, stores MIDI data
- VOC files: Voice, developed for Sound Blaster card by Creative Technology. Supports sampling rates of 8 and 16 bits, with or without compression
8. Qualities of Sound
- Nature of sound: Oscillatory movement of air particles forming directional longitudinal waves
- Waveform: Describes measurement of speed of the sound
- Amplitude: Relative loudness of the sound
- Volume: The amplitude determines the sounds volume, measured in decibels. Human hearing range from 1 to 120 decibels
9. Basic Qualities of Sound
- Valley and Crest: The lowest part of a waveform is reffered as valley and the peak point as the crest
- Frequency: No of crests that occur in one second is the frequency also called as Pitch
- Mono: Sound using only one channel
- Stereo: Sound using multimedia channels. Digital stereo uses two channels namely Left and Right
10. Analog and Digital Audio
- Analog: Continuous stream of the waveforms
- Digital: Finite numerical combinations representing the waveform
- Requirement of conversion: To handle the sound using computer(digital device) it needs to be converted into digital form
- Conversion Methods: Use of ADC (Analog signals => electrical impulses => ADC => Digital Sound)
11. Benifts of Digital Sound
- 100% reproduction
- Easily Editable
- Long Lasting
- Timely Retrieval on Demand
- Availability of Reliable Storage Media
12. Sampling/Resolution
- Sampling: The process of digitization of the analog sound
- Sampling rate: Number of samples per second
- Typical rate can range from 5000 to 100000 samples per second
- The number of bots used to store each sample is known as the resolution of the sound
MIDI: Musical Instruments Digital Interface
- MIDI is a simple digital protocol
- By connecting a computer to a keyboard through a MIDI connection, music can be recorded
- Many programs are supporting MIDI for communicating with synthesizers. MIDI files are widely used for exchanging computer music
References for content and images: Internet and multimedia books