AUDIO MEDIA 1

Created } “Borrowed” } Microphone MIDI keyboard CD’s & flash drives Internet Audio Sources 2

When dealing with audio media, there are two different approaches to recording, saving, and playing these media: Recorded Sound sound voice music 3

When dealing with audio media, there are two different approaches to recording, saving, and playing these media: Recorded Sound sound voice music 4 Synthesized Music music

When dealing with audio media, there are two different approaches to recording, saving, and playing these media: Recorded Sound sound voice music 5 Synthesized Music music

. WAVe (PC) .AIFf (Mac) .AUdio (Sun - Unix & PC)  Others Synthesized Formats .MIDi (PC & Mac) .RMI (PC) Waveform Formats 6

1. # of channels 2. Sampling rate 3. # of bits of sound When dealing with waveform sounds, there are 3 factors: 7 Let’s look at each of these in detail. Let’s look at each of these in detail.

Mono - 1 channel (track) Stereo - 2 channels (tracks) 8 Sound # of channels

1 second Continuous (analog) 9 Sound Sampling rate

1 second Sampled 25/sec. (digital) 10 Sound Sampling rate

Human hearing ,000 cps (Hz) 8 bits of sound 2 8 = 256 different frequencies 19,980 / 256 = 78 cps steps bits of sound 2 16 = 65,536 different freq. 19,980 / 65,536 =.3 cps steps Sound # of bits of sound

.WAVe files (record/play sound waves) voice - 11,025 times/sec. sampling rate 8 bit sound mono 3.5” floppy diskette holds 134 sec. 12 Sound # of bits of sound

.WAVe files (record/play sound waves) CD - 44,100 times/sec. sampling rate 16 bit sound stereo 3.5” floppy diskette holds 8 sec. 13 Sound # of bits of sound

.MIDi files (synthesize musical instruments) Like sheet music frequency (note) duration “voice” - (piano, drums, guitar, sax) 94 second score is only 28k 14 Music synthesized

WAVe vs. MIDi Although waveform files allow the recording, editing, and playback of sound, voice, and music, they usually require large file sizes. A typical voice recording in mono and with an 11 K sampling rate requires approximately 11,000 bytes/second and a CD quality recording in stereo with a 44k sampling rate requires approximately 176,000 bytes/second. Whereas, a typical MIDI file requires approximately 200 bytes/second! However, MIDI files can only contain the instructions to play music, and the creation of a MIDI file requires a MIDI device (keyboard) and musical talent. However, you can find MIDI editors on the Internet. 15

8 11 KHz / Mono lowest standard that should be used 8 11 KHz / Stereo no advantage in using stereo 8 22 KHz / Mono sounds like AM radio KHz / Mono okay for narrations KHz / Stereo CD-quality sound # of bits sampling rate uses File Size Considerations 16

Similar to what we saw with graphics files, depending on the format that is used, audio files can use different amounts of space. As an example, Diesel.au requires 380Kbytes while Diesel.wav requires 760 Kbytes. Although, AU files require less space, many applications, including VB, are unable to use sound files in this format. 17 File Size Considerations compressed vs. uncompressed

mp3 a challenge to CD’s? 18

mp3, m4a (used by Apple), and wma (used by Windows) are compressed audio files, but unlike jpg graphics files, these are not lossy compressions. That is, the audio files are compressed, but when uncompressed, they are restored to full quality. The compression/decompression is usually done by software and are known as codecs. 19 mp3 a challenge to CD’s?

As an example of the amount of compression, I have two versions of Freebird. Freebird.m4a is a 8.6 MB file While Freebird.wav is a 93.8 MB file The m4a file is only 9% the size of the wav file 20 mp3 a challenge to CD’s? A portion of Freebird.wav is used in our next assignment. A portion of Freebird.wav is used in our next assignment.

AUDIO SOFTWARE 21

Audio Software Media Player (Windows) - player for WAV, WMA, MID, and many other audio file types. Sound Recorder (Windows) - recorder for WMA files. Goldwave ( - editor, player, recorder, and converter for numerous audio file types. Audio Studio ( - editor, player, recorder, and converter for numerous audio file types. 22

Consider the following example: 23 Several years ago when I was using PowerPoint 97, I wanted to use DIESEL.AU, a file that I found on the Internet, as a sound effect in my presentation. However, PowerPoint 97 (and VB 2010!) only play WAVe files, and the file was too long (48 seconds).

24 Consider the following example:

48 seconds 25 Consider the following example:

14 seconds 26 Consider the following example:

27 Consider the following example:

Download vs. Streaming 28

Received first, then played Software is needed to: create play Initial download “Buffered” ongoing download with simultaneous play back Software is needed to: create serve play 29 Download vs. Streaming

30 Amount downloaded Amount played

Audio Sound.WAV.SND.AU … etc. Music.MIDi.MP3/.M4A.RA/.RAM.ASF.MP3/.M4A (Downloaded) (Streamed) 31

For this course, we will learn how to integrate existing wave files into VB programs. 32

My.Computer.Audio 33 Other than a brief reference to My.Computer on pages 88 and 89, the text does discuss this topic. However, consider the following references: us/library/cf1shcah(VS.90).aspx us/library/microsoft.visualbasic.devices.audio.stop.aspx

Read the Description of Assigment-9 34