Lecture 5 - Capturing and Editing Digital Audio PDF

Lecture 5 Capturing and Editing Digital Audio Copyright © 2016 Pearson Education, Inc. All Rights Reserved Learning Objectives 5.1 How to acquire sampled digital audio. 5.2 The basic workspace of digital audio editing programs. 5.3 The basic techniques of digital audio touc...

Lecture 5 Capturing and Editing Digital Audio Copyright © 2016 Pearson Education, Inc. All Rights Reserved Learning Objectives 5.1 How to acquire sampled digital audio. 5.2 The basic workspace of digital audio editing programs. 5.3 The basic techniques of digital audio touch-up. 5.4 The common techniques of digital audio alterations. 5.5 How to embed audio on Web pages. Copyright © 2016 Pearson Education, Inc. All Rights Reserved Ways to Acquire Digital Audio Record Digitize analog medium Hardware Software Copyright © 2016 Pearson Education, Inc. All Rights Reserved Recording: Hardware / Software Requirements Computer with a sound card Microphone – Unidirectional – Omnidirectional Digital audio recording program Some common programs: – Adobe Audition – Sony Sound Forge – Audacity (free, open-source) Copyright © 2016 Pearson Education, Inc. All Rights Reserved General Steps For Recording With a Digital Audio Program 1. Start a new file 2. Specify settings: – sampling rate – bit depth – number of channels 3. If possible, – run through or rehearse the audio you want to record while observing the sound input level – adjust the sound input level so it stays below the red area for the whole audio run-through 4. Hit the record button to start recording, stop button to stop Copyright © 2016 Pearson Education, Inc. All Rights Reserved New File Dialog in Audition/ Sound Forge/ Audacity Copyright © 2016 Pearson Education, Inc. All Rights Reserved Field/Outdoor Recording (2 of 2) Voice recorder apps on cell phones: – Not intended for high quality audio – Usually mono – File format: Lossy compression to produce smaller file size suitable for email and uploading to Web from the phone Handheld recorders: – Sony PCM-D100 – High quality stereo recording – Recorded to internal memory or memory card – Also support USB transfer to computer – File format: WAV and MP3 Copyright © 2016 Pearson Education, Inc. All Rights Reserved Digitizing Analog Medium Connect the line-out port of your analog medium playback device to the line-in port on your computer Rehearse the playback of the analog medium to determine the best input level Start recording using digital audio recording program before start playing the analog medium Copyright © 2016 Pearson Education, Inc. All Rights Reserved Basic Audio Editing Basic workspace elements: Waveform display – X-axis: time – Y-axis: audio amplitude – mono: 1 waveform – stereo: 2 waveforms on top of each other Transport controls (play, record, rewind, fast forward buttons) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Audio Mixing: Working with Multiple Audio (1 of 2) Example applications: Record audio clips separately and mix them later mix multiple instrumental playback where each is recorded as a separate audio compose audio with multiple clips voice-over with background music Audacity: – Add audio track by choosing File > Import > Audio... Copyright © 2016 Pearson Education, Inc. All Rights Reserved Audacity (2 of 2) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Spectral View (1 of 2) Another representation of the digital audio in addition to waveform Useful in: analyzing the frequency range of the audio selecting the frequency range of the audio identifying audio distortion due to frequency anomaly blank x-axis y-axis color waveform view time amplitude -- spectral view time frequency of the amplitude audio Copyright © 2016 Pearson Education, Inc. All Rights Reserved Audacity Spectrogram Copyright © 2016 Pearson Education, Inc. All Rights Reserved  Parallels between Basic Digital Image and Digital Audio Editing Basic Digital Image Editing Basic Digital Audio Editing Reassemble image content by cutting, Reassemble audio waveform by cutting, copying, and pasting copying, and pasting Adjust tonal value Adjust volume Clean up dirt, dust, and scratches Noise reduction Resize the image Resample the audio Reduce the image’s color depth Reduce the audio’s bit depth Apply filters for special effects Apply filters for special effects, such as fade-in/fade-out, reverb and pitch changes If you want to save your file as JPEG If you want to save your file as MP3 for the for the Web, wait until the last step Web, wait until the last step because MP3 because JPEG uses lossy compression uses lossy compression Copyright © 2016 Pearson Education, Inc. All Rights Reserved General Steps of Digital Audio-Recording Touch-up 1. Noise reduction 2. Trimming 3. Adjusting volume level Copyright © 2016 Pearson Education, Inc. All Rights Reserved Uses of Digital Audio Video Multimedia authoring Playback on the Web Audio CD Podcast Copyright © 2016 Pearson Education, Inc. All Rights Reserved Video Export audio and import it into the video editing program Most video editing program support: –.wav – mp3 Some audio editing program, such as Adobe Audition, let you import video – can synchronize audio with the video Copyright © 2016 Pearson Education, Inc. All Rights Reserved Playback on the Web Best if small file size for less wait time HTML5 audio Streaming format Progressive download Copyright © 2016 Pearson Education, Inc. All Rights Reserved Methods to Play Back on the Web Embedding the audio on the Web page – HTML5 audio Played using the browser’s built-in player – Non-HTML5 audio Played using plug-in or external player Linking to the audio file – will cause the file to play in an external player window Copyright © 2016 Pearson Education, Inc. All Rights Reserved HTML5 Audio Supported formats: MP3, ACC (MP4), OGG Vorbis, and WAV HTML5 tag: Example usage: An introduction of HTML5 video and audio is covered in future lectures Copyright © 2016 Pearson Education, Inc. All Rights Reserved Podcast Podcast: – a collection of files available on a Web server – usually audio files – can be any types of files: Web pages, text, PDF, images,... Episode: Each file in the podcast Feed: – The text file that lists the internet addresses of the files in a podcast. – Posted on a Web server – People subscribe to the feed Copyright © 2016 Pearson Education, Inc. All Rights Reserved General Steps to Podcast Audio (1 of 2) 1. Create Your Audio Content in MP3 2. Put Your MP3 Files on a Web Server 3. Create Your Podcast Feed File: An XML file that lists these information of each episode: – title – internet address – author – description – length and type of the audio – publication date Copyright © 2016 Pearson Education, Inc. All Rights Reserved General Steps to Podcast Audio (2 of 2) 4. Publish Your Podcast Feed – Post your feed file to a Web server and make a link to the feed file like you would post and link any other content. – Icons used for the link: Copyright © 2016 Pearson Education, Inc. All Rights Reserved