What is the "Text to Speech" add-on and how can I use it?

This extension is meant to read the active document for you. All you need to do is to select the part of the document that is needed and then press the toolbar button once to allow the extension to bring the TTS popup up. The extension parses the selected document and starts reading it. The current paragraph is going to be highlighted and scrolled into the viewable port. You can always jump to the previous or the next section using the onscreen buttons. Note that in the TTS popup, there is a dropdown list to change the active TTS engine. You can use local or remote resources. Also, you can alter the reading speed, or the volume to fit your needs.

What's new in this version?

Please check the Logs section.

What is the difference between the local and remote TTS engines?

There are two different sources for TTS. Either your operating system provides the engine and your browser just sends the content to this engine or the browser has its engines. Most of the engines that are offered by your operating system are local TTS engines which means that the text is converted to voice without any server interaction, or all the conversion process is local to your machine. This type is useful when there is a privacy concern about the content that is being remotely shared. However, these local engines are not that powerful and the converted text does not feel like a human-generated voice. The remote engines use a remote service that takes the text content and converts it into a human-quality voice. Usually, these engines use the neural network or machine learning to improve the quality of the generated voice and hence the quality of the output is usually more acceptable.

How does this extension treat the local and remote engines?

This extension internally uses the text-to-speech library by @belaviyo. In this engine, a when a local TTS core is used, the entire content is sent to the engine in one request since the engine does not use any server interaction and hence there is no limit on the length of the content. Since the engine has access to the entire content, it can decide how to pause between the sections. However, when a remote resource is selected, the extension needs to split the entire content into a set of small segments that the length of each section would be in a range of acceptable length by the TTS engine. Hence the library tries to split the content from its breaking points (like dots for instance). If there are still some lengthy segments, there is no option other than splitting the segments from the middle of sentences.

My operating system does not support any TTS engine. Can I still use this extension?

Yes, the TTS library offers a few remote TTS engines. Currently, IMB Watson and Google Translate TTS engines are supports. In this extension, we only support the Watson engine in different languages, since there is no free API for the Google Translate one.

How can I know if the extension is enabled?

When the extension is enabled, the toolbar button is colorful and if your mouse is placed over the toolbar button, you will get the status in the tooltip area.