Module 11: Let's Digitize


Before Entering This Module


Introduction

In this module, you will walk through the steps in the digitization process and learn about editing techniques for your audio. As you digitize your audio-cassettes (or other materials), you will also begin to document and record their relevant information in your digitization log. This module also provides information of best practices for maintaining and adding to your digitization log.

This module heavily references information presented in previous modules including Module 6 about metadata and Module 1 about file naming conventions. If you would like a refresher on either of these topics, please follow these links to review these lessons:

 

Your Copy Files

While you progress through the digitization process, you will begin to save and categorize different copies of your recordings. It is important to know what each type of copy file will be used for and to keep them organized. In the module, there are descriptions of each type of copy file you will generate and save. This information is presented here for quick reference and your convenience:

Copy File

Description

File Type

Copy File

Description

File Type

Preservation Master

The preservation master is a file that will be saved in the lossless format of WAV. It is as close a copy of the original recording as possible. It will have a checksum embedded, along with other metadata. It will be accessed only when the access master has become corrupted or lost.

WAV

Access Master

The access master is also a high quality, lossless format of WAV. Improvement to sound quality, normalization, or removal of silence can be done to the access master or at the preservation master level.

WAV

Access Copy

The access copy is created from your access master and is a file that is most easily shared and uploaded to websites or other platforms. In addition noise reduction and other effects can be added to the access copy for ease of listening.

MP3

You will be using BWF MetaEdit to embed MD5 checksums. These are a unique set of 32 numbers that get added at the beginning of the audio file. If there is a change to the data in the file then it will generate a new checksum, and you will be able to see that a change was made using BWF MetaEdit.

Editing Audio

It may be necessary to edit your audio file as an access master (or even preservation master). Common processes include the removal of silence, usually at the beginning and end of your recording, and normalization.

Removing or trimming silence is done primarily to reduce the file size of recordings. The removal of silence should be consistently applied to all media that you digitize if you decide to make this edit. If you decide to trim silence on the preservation master, you should also trim the silence on the access master. However, if you only trim the silence on the access master, trimming it on the preservation master is optional.

Normalization is a function performed over sections of your recording to even out and reduce any spikes in the waveform. These spikes are also known as 'transients' or 'transient bursts'. If the spikes exceed the sample rate of your recording, the audio will be clipped. Normalization applies a level gain amount to an audio recording to make the waveform more consistent. It is recommended that you normalize only the access master. The preservation master should remain as close to the original recording as possible, and normalization will observably change your recording.

In this module, there are videos and knowledge checkpoint exercises to acquaint you with these processes and assess your understanding of how they are applied to your files.

If you are interested in other methods of editing audio quality, you can go through this related article and its tutorials, located on the FirstVoices Knowledge Base: https://firstvoices.atlassian.net/wiki/spaces/FIR1/pages/1704440

Exporting from Audacity

When you are ready to export your data, you will need to perform the process three times to get your three copies: one preservation master, one access master, and one access copy.

It is important that you follow naming conventions consistently when you export and name your copy files. When exporting the preservation master and access master, you will export as WAV while you will export a MP3 in the case of your access copy.

When you stop recording in Audacity, the file will not automatically save. If you need to step away from your computer, you can 'save as' an audacity file using the 'save as' option under the File menu. You will still need to export the file to create WAVs and MP3s when you return to your workstation.

This module contains tutorials and step-by-step instructions to successfully export WAV and MP3 files from Audacity. There are also examples for naming your various copy files to identify which side of the cassette tape they might contain and the type of copy file they are.

Embedding in BWF MetaEdit

Once you have successfully exported your preservation master and access master copy files, you can import them into BWF MetaEdit.

BWF MetaEdit will incorporate and embed checksums on WAV files; it will not allow you to import your access copies into it. In BWF MetaEdit, you will be able to add information into the various columns it assigns to your files that you selected while installing it and choosing its settings.

If you encounter any error messages in the program, navigate to the Help tab on the top of the BWF MetaEdit pop-out window. Proceed to click the Help option with the "?" icon. You then will be taken to the BWF MetaEdit Help page. If you select Errors on the top of the window, the page will provide you information about error messages and what they mean if they appear in the application. You also will have the option to read more about checksums and possible workflows embedding for metadata by selecting these respective tabs on the same page.

This module contains tutorials and step-by-step instructions to successfully upload and embed additional metadata in BWF MetaEdit. If you have additional questions about messages or warnings you encounter in the program and cannot find the answers on the BWF MetaEdit Help page, please contact Ben (ben@fpcc.ca) or James (james@fpcc.ca).

Throughout the digitization process, you should perform regular self-checks to make sure you have documented and recorded the correct metadata in your digitization log for each of your copy files.

Link to Interactive Module

Please follow this link to take you to the interactive module:

https://digi-training.s3.ca-central-1.amazonaws.com/lets-digitize/index.html

Relevant Documents

Digitization has provided some resources for you to review on how to normalize transients in your audio and the process from beginning to end of creating your copy files. There is also a digitization log template supplied. This information is also downloadable and available within the module itself.

Editing Transients

Digitization Workflow

Digitization Log Template

 

After completing this module, please feel free to review it again or continue onto the next one.