Location Aware Music Player

By

Kevin West

David Zhao

Basic Concept

A music player that knows where you are. Play different music in different parts of your

house. Finish the song you are listening to right as

you reach your destination. Great for students traveling in between

classes, who hate being interrupted.

Basic Scenario

People listen to different types of music when they are at different places.

A person may want to listen to heavy music when he’s working out at the gym.

He may want to listen to classical music when he’s studying in his room.

Basic Scenario (continued)

Solution: Detect the current location and play different

types of music according to the location.

Basic Scenario (continued)

A student is listening to his mp3 player between classes. By the time he reaches his next class though, he still has over a minute to go on his favorite song. He’ll have to stop it to listen to the professor.

What if the song had already ended?

Basic Scenario (continued)

Solution: Figure out how much time until user reaches

next destination. Alter the speed of music playback subtly to finish the track when the user arrives.

Architecture - Components

Music Player Location-Detection: Placelab Location analyzer Sound speed adjuster

Expected Effort

Pieces to be built: Placelab Analyzer: Interpreting Placelab data

to determine a location, and a velocity towards next location.

Audio Speed Adjuster: Speeding up and slowing down the audio stream without significant loss of quality.

Expected Effort (continued)

Minimum Functionality: Determining a location and playing the

correct music. Determining the velocity and adjusting the

stream to finish as the user gets to his location.

Expected Effort (continued)

Desired Functionality: Fading in between different streams as you

enter a new location. Adjusting the audio speed in such a way that

the change is invisible to the user.

Unknowns

How accurate is Placelab? Can we get a good velocity reading?

Can we change the audio speed without pitch shifting or losing significant quality?

Algorithmic Design

The Problem: Given a set of songs with specific lengths, minimize the speed changes in the audio.

Example: Song 1 = 3 min, Song 2 = 3 min, We will arrive in 5 min. We can adjust Song 1 to be 5 min, or adjust both to be 2.5 min.

Burning Questions

Will we be able to do speed adjustment of audio quickly enough to be unnoticed?

Can placelab provide accurate information on velocity?

Evaluation

Performance Tests Quality of speed-altered sound Accuracy of estimated arrival time

Usefulness How much does the user care for location-aware

functionality?