Echo Cancellation, Art or Science? Part IV

  • On November 19, 2016
Background In the previous posts of this series we discussed the challenges of echo cancellation algorithms to efficiently handle the echo path,  the complexity introduced by  echo invalidation and the howling effect. In this post we will discuss another important aspect with regards to echo cancellation called Saturation.
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Echo Cancellation on Android – synchronizing the input

  • On November 19, 2016
Background In this post we will discuss the challenge of synchronizing the audio that is given as the input to the echo cancellation software running on Android. This post is a continuation to a blog series we published on echo cancellation and specifically on the post that deals with importance of synchronization in echo cancellation. […]
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Echo Cancellation, Art or Science? Part III

  • On November 18, 2016
Background In previous posts on echo cancellation we discussed the challenge of echo cancellation algorithms to efficiently handle the echo path, especially when it is long and volatile, and the complexity introduced by the invalidation phenomena.  In this post we will discuss another aspect in echo cancellation called Howling.
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Echo Cancellation, Art or Science? Part II

  • On November 18, 2016
Background In the previous post on acoustic echo cancellation we discussed the importance and the challenge in handling of the echo path. In this post we will discuss a different aspect that echo cancellation algorithm must handle. It is not rare that users change the setting of their audio device during a call. For example […]
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Echo Cancellation, Art or Science? Part I

  • On November 18, 2016
Background First, let us apologize that this post is going to be a bit technical. Don’t worry we will try to keep it as simple as possible.  Echo cancellation, and more specifically Acoustic Echo Cancellation (AEC) is theoretically a very simple algorithm. The AEC algorithm receives a reference signal (i.e. the audio played to the […]
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VoIP on Android – volume control

  • On January 16, 2016
Background In our previous posts we covered few of the difficulties that Android VoIP developers are facing – for example the challenge in providing high quality echo cancellation. In addition to the echo cancellation, the variety of hardware platforms that are running Android also introduces a challenge in controlling the volume of the voice.  
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How can echo suppression badly impact call quality ?

  • On January 16, 2016
Background Can phones/soft-phones with built-in echo suppression badly impact the audio quality? Surprising as it may sound the answer is positive. In other words, when a call center, or any other organization, purchase phones with built-in echo suppression it is jeopardizing the overall call quality.  In order to analyze the reason for this phenomena we […]
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Echo Cancellation on Android and AudioRecord

  • On June 5, 2015
Background When developing a VoIP application, most implementations use AudioRecord as the foundation class for capturing audio from the microphone.  Can this class be used to cancel echo as well ?  
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Echo Cancellation and silence

  • On March 11, 2015
Background Following our previous post on synchronization, in this post we would like to cover a specific aspect of un-synchronized input which causes the speakers to play silence that is not monitored and therefore unknown to the AEC.
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