Skip to content

Latest commit

 

History

History
69 lines (48 loc) · 3.06 KB

backend-task.md

File metadata and controls

69 lines (48 loc) · 3.06 KB
Raw

Waveform Generator (Backend Take-home Task)

The task solves a real-world problem related to converting an audio file into a useful waveform structure. Waveforms are a key way for our customers to visualize speech data.

We recommend writing answers in whatever language you’re most comfortable in. Like our own code, we expect testing instructions: whether it’s an automated test framework, or simple manual steps.

Brief

Write a program to consume the raw output from an audio silence detection filter and convert it into a useful format for consumption by other APIs. The ffmpeg command has been run for a sample call and we've linked the raw data for both the user channel, and the customer channel.

The files contain data about a real conversation between two parties on a conference call with the following structure:

[silencedetect @ 0x7fa7edd0c160] silence_start: 1.84
[silencedetect @ 0x7fa7edd0c160] silence_end: 4.48 | silence_duration: 2.64
[silencedetect @ 0x7fa7edd0c160] silence_start: 26.928

For simplicity, the largest point in the dataset represents the total duration of the call.

Requirements

  1. For each channel, the data needs inverting to show when audio was active and stored as a series of points. This is based off silence_start and silence_end values. The unit of these values are seconds. For example, the above would translate to [0, 1.84], [4.48, 26.928]

  2. Determine the longest un-interrupted speech (monologue) for each channel (stored as longest_user_monologue and longest_customer_monologue.

  3. Determine the percentage of time the user talked over the entire call duration (stored as user_talk_percentage).

  4. You'll return the following JSON structure:

{
  "longest_user_monologue": 416.18,
  "longest_customer_monologue": 1152.82,
  "user_talk_percentage": 41.92,
  "user":[
    [0,3.504],[6.656,14],[19.712,20.144],[27.264,36.528],[41.728,47.28],[49.792,61.104],[65.024,79.024],
    [ ... and many more ...]
  ],
  "customer":[
    [0,1.84],[4.48,26.928],[29.184,29.36],[31.744,56.624],[58.624,66.992],[69.632,91.184],
    [ ... and many more ...]
  ]
}

Coding Standards

  • Use git to version control the application
  • Scaffolding should not be used to generate any code
  • Not using a web framework is an advantage
  • Include instructions in a README on how to run the application

The solution would be reviewed with best practices in mind. These would include but won't be limited to the following:

  • PSR compliance
  • strict types, property types, return types, etc
  • composer (autoloading, platform requirements, dependencies)
  • Unit tests /w test doubles
  • IoC friendly code

Make sure your solution is able to run on a supported version of PHP.

Submission

Please publish your submission to GitHub/GitLab/BitBucket in a non-publicly available repository.