How to control the auto speech acceleration feature for my presentation?

How to control the auto speech acceleration feature for my presentation?

Do you need to create a simple voice over for your presentation?

This is why we exposed 2 new controls on the Dubbing Editor’s screen.

The first is the Max Auto Speech Acceleration:

Voice Acceleration Control

Using this slider, you can lower the automatic acceleration to a minimum or even remove it all together. The value you select (0-20%) enables the engine to accelerate, but only if needed (meaning only when the timing provided for the subtitle, isn’t enough to pronounce the whole sentence, at its default speed).

This means that if you allow 10%, then (only when needed) the engine will auto accelerate to match the subtitle’s timing, at a maximum of 10%. If it’s still not enough, the engine will start lagging, till it will have enough space between the subtitles to catch up. This is basically the same behaviour any professional narrator will do, if the amount of content needed to voices, exceeds the timing available, e.g. when dubbing a German video with the original is in English, the speaker will need to accelerate in most sentences, because German is approximately 20% longer than English…

Here’s a story, which I mentioned in an earlier blog post that signifies the importance of this issue: During the 60s, the Americans started exporting movies to West Berlin and were dubbed to German. Since German language is around 20% longer than English, the narrators had to speak 20% faster… In the 80s, when the Berlin wall was teared down, you could differentiate a West Berliner to an East Berliner, just by the natural speed of their speech…

So, when creating a voice over for a presentation, having the voice accelerate or slow down, might not be useful, so you can simply reduce it to 0%, and run the project again, to hear the result.

This is relevant if you created the voice over on top of a video, on top of a music track, or simply ran just subtitles of transcription, without any media. Check out the ‘How does it work?’ section, to review all of the possible work flows that our engine can cover.

Do you need to add a simple voice over with a music background to your presentation?

Another feature we recently added is the original actor’s volume while voice-over slider, which gives you the ability to modify the background voice volume after the project was run.

Voice Removal Filter

Several users complained that viewing the video dubbed, helped them understand what should be the exact amount that should be used of the background voice removal filter.

Since our filter is focused mostly on human voice frequencies, it usually affects very little the background music or effects (M&E) at the higher values (80-90%), while dramatically lowers the volume of the original actors in the video’s sound track. Only once you select a value lower than 60%, you start noticing the affect on the M&E. Of course, if you have a piano playing at the same frequencies of human voice, it will be affected as well.

To sum up, here are our rules of thumb for this filter:

  • If you want to keep the music and effects unharmed, or if you have a clean M&E track (i.e. music and effects background without any human voice), keep the value at 100%. Our engine will not filter any of the audio, keep that value above 90%
  • Below 50% you will remove some the music and effects from the sound track, till 0% which will produce clean silence as a background to the digitised voices
  • If you want to keep the original voice at a lower volume while having the digitised voices stronger than the background volume, keep the value between 60%-90%. Our engine will its best to keep the music and effects in the background while focusing on removing most of the human voice

Remember that both filters will affect the audio only once you click the ‘Save & Get a Preview’ button at the bottom of the Dubbing Editor screen.

If you would like to know how to paste text, without syncing to time, which could be useful for presentations, read our previous blog post about our special transcript pasting feature.

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