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Written by Administrator   
Thursday, 17 October 2024 18:28

Keyboard shortcuts

 

Press CTL-ALT-CMD (⌃⌥⌘) simultaneously

+ S = Toggles the subtitle overlay on or off

+ UP = Increases the size of the subtitle font

+ DOWN = Decreases the size of the font

Background and use.

The app was initially created as an aid for people with hearing disabilities but proved to be very useful for hearing people as well.

For hearing disabled people, It allows you to keep looking at the screen while having a conversation where other people's speech is picked up by a microphone connected to your Mac.

For all, so bad/non-hearing and hearing people, with an audio loopback driver (like BlackHole (1) or LoopBack (2)) selected, video applications such as Facetime or Quicktime or podcasts, movies and live TV via a web browser can be subtitled live without the need for physical speakers to be switched on and maintain silence in the room.

Working.

Audio picked up by a microphone or driver is broken into chunks and sent of the internet to Apple's speech services. On some powerful and properly configured Macs the conversion might be performed locally. The speech is converted into readable text and projected as an overlay on top of all other windows, usually even if they are in fullscreen mode. However, some other apps may forcefully grab full focus of a screen pushing the subtitles to an invisible background.

A built-in LED bar can be used to visualize whether there is sound on the input channel at all. Just next to it a percentage of "confidence" pops up sometimes. Be aware that this is not the accuracy of the transcription but the confidence level of the machine transcribing. It can happen that the output, the transcription is 100% correct but the confidence surprisingly low and vice versa. It's more an indicator of the quality of the input which the machine is trying to understand.

Currently the user still needs to select the language the spoken text is in. The app can not detect the language automatically (yet). In the preferences this language can be set next to a number of other settings like the view characteristics of the subtitles.

Be aware that when the subtitles are turned on, the overlay blocks the area on the screen for interaction with other apps. You can either turn the subtitles off (CTL-ALT-CMD-S) temporarily of just grab the subtitle area with your mouse and drag it to anywhere else on the screen. Since it is in fact a window with invisible borders, you could still resize the window by grabbing its sides. In the preferences-system there is check to turn the window borders on in the same color the subtitle text is. Useful for learning how to use the app but not recommended for experienced users.

And finally, it is highly recommended to switch the subs off (CTL-ALT-CMD-S) when you don't need them. Since it is an overlapping window, handling of content of underlying windows can be more complicated or even impossible. The app "lives" in the top bar of your screen so it always listens to your toggle.

What if it does not work out of the box?

The first thing you need to check is the input source found in you Mac's preferences. For example, if you want to grab speech around you, the input source should be a microphone. If you are watching a podcast or movie, the input source should be a driver which feeds sounds to the input. Make sure that with some 3rd party drivers you have to feed the output not to the speakers but to the driver as well. You could also use real audio so sound from the speakers you have is picked up by the Mac's microphone. However, this can cause unwanted audio feedback loops. So testing what are the most convenient and practical use cases, is not a waste of time.

Some defaults.

The defaults are set to your own preference. However there are some recommendations:

  • Alignment LEFT. Why? Because it is more stable and therefore less distracting. Remember that in movie complete sentences are displayed at once and even just before the speaker starts. In that case a CENTER alignment is the better choice. However with real time subtitling we display word for word to follow the speed of the speaker. Waiting for a sentence to complete would be much too slow.
  • Color GREEN. Why? Because green is avoided on TV and movies. "Green-screens" are used to create artificial backgrounds so exposing a solid green color would make things complicated for the movie editor. Of course you can make a different choice.
  • Border OFF. Why? You can move the subtitles to anywhere and any size on your screen but sometime it is handy to see what you are doing. More experienced users know where the corners of the subs are but to learn what is most useful for you, switching the border on temporarily to move or resize the subs can be convenient.

Privacy and security.

This app does not store audio or transcribed text for more than a few seconds. However, unless a powerful Mac transcribes speech locally, pieces of audio are sent to Apple's servers to convert speech to text. Just like that also happens for Siri. The app has no means to avoid or manage that. It does not use or track any sound or transcription.

The only data that is stored are the app defaults in the preferences.

Keep in mind that, for example, if you watch a video stream with a virtual loopback microphone and with physical speakers turned off, someone else in the room may be looking over your shoulder and reading the closed captions on your screen.

Disclaimer.

Transcribing spoken text is a difficult task and is certainly not 100% error free. It is best performed by powerful machines of big service providers like Apple and Google. Nevertheless the results may vary depending on:

  • The quality of the input like the loudness, accent and articulation of the speaker and the background noise;
  • The speed and quality of the local network and internet;
  • The language. English is by far the language which is transcribed best. Simply because the majority of research and development in speech recognition is done in and with the English language. The “smaller” languages like Dutch get less attention so the quality of the transcription will be a lot less as a result. It makes the need for excellent input quality even more important.

That said, the subtitles you see can never be better than given the quality of the input and what Apple's services can provide. This app can't do anything to improve that.

However, results are expected to get better over time, even already in the near future. Since the rapid rise of AI applications, speech recognition has gained momentum.

we are not connected to or endorsing other software developers like from BlackHole or LoopBack. They are just examples of loopback drivers which may  or may not work on your specific Mac. We are never responsible for the working or performance of these drivers. However, using a driver like these would make this app a lot  more versatile.

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(as per October 2024)

(1) BlackHole from https://existential.audio/blackhole/

(2) LoopBack from https://rogueamoeba.com/

Last Updated on Thursday, 17 October 2024 18:36