Too Much Music?
By Mark Ireton, Cirrus Logic -- document.write(get_publication('Electronic News'));Electronic News, 6/24/2003
you ever try to memorize all the contents of an “Album” with 450 tracks? Did you ever press the next button 350 times because you listened to track 20, and then decided that you wanted to listen to track 370 next? Ouch!
A single CD can contain over 450 WMA tracks, for a hard drive player with a 20GB drive this increases to over 13,000 tracks! For MP3/WMA CD players to be successful it is vital that a music lover can conveniently locate the music that he wants.
Typical CD players have a simple segmented LCD display that shows only the current track number. In many 1st generation CD-MP3 players this display format was continued, leading to many disappointing 1st generation products. This is somewhat surprising given the almost ubiquitous use of character displays on solid state MP3 players, but was driven by both cost, and the desire to continue use of the same micro-controllers and user interface software from CD players.
Conveniently accessing the more than 450 tracks that can be stored on a single CD requires the use of a text based UI that can represent both the organization of the music and the specifics for each particular track. The simplistic 1st generation text based UIs replicate a PC centric directory/file representation of the music. This is usable, but is far from ideal. Use of a more powerful micro-controller for the MP3 player enables the comprehensive information stored in ID3 and other meta-data tags to be utilized to create an interface where the music lover can brows the available music by Artist, by Album, by Genre, by Composer, etc..
The display module is a critical component in the creation of an easy to use user interface. Displays on consumer music players are often viewed from a distance and readability is dictated by a number of factors. Your display module selection will depend on a matrix of requirements but the following characteristics must be considered.
First off, never forget “fashion”. This is a consumer product, and retail value is often determined as much by “coolness” as it is by player functionality. If you are making a portable music player, expect your customers to wear it. Display brightness and contrast determine the readability of the display from a distance and the viewing angle dictates the ease with which the display can be read from various points within a room. Just as important is the selection of either a color or a mono display as this has a direct impact on the design of the visual interface.
The implications of supporting hundreds, or thousands, of tracks on a portable music player extend well beyond the selection of an appropriate display.
Organizing the music data in real time to enable the music lover to browse the content without irritating delays requires the considerable processing power that can be provided by a 90+MHz 32-bit RISC microprocessor. Sophisticated firmware and large content database require access to extensive system memory that can be provided at low cost by the SDRAM that is included in an MP3-CD system to support Electronic Shock Protection (ESP).
The primary user interface requirement is “The UI should make selection of the music I want to hear, easy and quick.” A CD-MP3 player is an entertainment system. The UI should add to the entertainment experience, should make listening to the music more exciting – more interesting.
In the future, the UI must support three modes of listening: passive, active, and explorative. Passive listening is where the music lover is primarily doing something else, and the music is in the background. Passive listening is supported by selecting “categories” of music; an Artist, and Album, a Genre and enabling random, repeat, etc. playback.
During active listening, the music lover is actively browsing the music on the player and selecting tracks. A “playing now” playlist supports this activity. Selected tracks are appended to the playing-now playlist and the player navigate functions enable movement among the selected tracks.
“Explorative listening” is an entirely new mode of listening to music that has not been possible with past generations of music players. During explorative listening the music lover is accessing on-line information about the artist, album etc while listening to the music. As the music lover browses this information, the music system is recommending music tracks to listen to, and if selected appending them to the now playing playlist. Entertainment is key. Listening to music is entertainment, and explorative listening adds to that entertainment experience.
The “language” of a user interface evolves over time as successful paradigms become universally adopted. For compressed audio music players we are still fortunately far from this Nirvana. This creates an opportunity. Create a product and get the UI right and you have the potential for a market dominating music player.
Author Information
Based at Cirrus Logic's headquarters in Austin, Texas, Dr. Mark Ireton holds a Ph.D. in digital signal processing for speech compression and has been active in the field of compressed digital audio for over 17 years. Dr. Ireton can be reach at mark.ireton@cirrus.com
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