When most people think of digitised music, they think MP3. Yet once the MP3 music starts playing, it's clear to most listeners that the quality offered by MP3's low data rates is not particularly good. Other formats like Advanced Audio Coding (AAC) can provide better sound. Even better are what is known as loss-free codecs like FLAC. These have a cost too, through relatively large file sizes. Choosing the right codec is a question of determining how the music will be used.
"MP 3 grew up with the Internet and was a very good codec in its day," says Gerhard Stoll, an engineer for audio system technology at the Institute for Radio Technology in Munich. Yet significantly better standards are available today, including the AAC format, itself an advancement of the MP3 standard.
The improvement can be traced, among other factors, to the fact that quality no longer sinks proportionately to data rates, Stoll explains. AAC achieves CD quality at just 128 kilobits per second (kbit/s). Both MP3 and AAC involve cutting out the portions of the audio range inaudible to the human ear from the music. For this reason the processes are known as lossy.
Another lossy format, AAC Plus or HE-AAC, was developed specifically for low-bandwidth streaming over the Internet, radio or cellular phone systems. An AAC Plus data rate of 48 kbit/s is comparable with 128 kbit/s in an MP3 file. "An MP3 file by contrast is unlistenable at 48 kbit/s," Stoll says.
Most current MP3 players can handle the MP3, AAC and WMA formats, Stoll continues. WMA stands for Windows Media Audio, Microsoft's lossy answer to MP3 and the standard format for many download or streaming music portals on the Internet. Apple's iTunes shop by contrast works with AAC, and that move is not without consequences.
"AAC became dominant among Apple users and is already more widely distributed than MP3," says Christine Tantschinez, test editor at Stuttgart-based Audio magazine. MP3 will not completely disappear, she thinks, but playback devices will be able to handle more and more formats in the future. "In terms of sound and efficiency, AAC has the better future prospects, though."
To avoid distortions, music should not be transcoded into the MP3 format at rates of less than 192 kbit/s. "You can even consider data rates of 256 kbit/s or more, although almost very little difference can be heard in that range," is the recommendation from the Fraunhofer-Institute for Integrated Circuitry in Erlangen. To discourage users from trying to wring out savings on the wrong end of the spectrum, however, the free codecs Musepack (MPC) and Ogg Vorbis only start at around 160 kbit/s.
Lossless codecs are the choice for those who refuse to tamper with the music. They work by compressing the existing data into itself. This retains the original sound but can cut data size by half, Stoll says. In principal the codecs differ from one another only in terms of compression and decompression speeds. The open source Free Lossless Audio Codec (FLAC) has a slight edge in that department.
"MP 3 grew up with the Internet and was a very good codec in its day," says Gerhard Stoll, an engineer for audio system technology at the Institute for Radio Technology in Munich. Yet significantly better standards are available today, including the AAC format, itself an advancement of the MP3 standard.
The improvement can be traced, among other factors, to the fact that quality no longer sinks proportionately to data rates, Stoll explains. AAC achieves CD quality at just 128 kilobits per second (kbit/s). Both MP3 and AAC involve cutting out the portions of the audio range inaudible to the human ear from the music. For this reason the processes are known as lossy.
Another lossy format, AAC Plus or HE-AAC, was developed specifically for low-bandwidth streaming over the Internet, radio or cellular phone systems. An AAC Plus data rate of 48 kbit/s is comparable with 128 kbit/s in an MP3 file. "An MP3 file by contrast is unlistenable at 48 kbit/s," Stoll says.
Most current MP3 players can handle the MP3, AAC and WMA formats, Stoll continues. WMA stands for Windows Media Audio, Microsoft's lossy answer to MP3 and the standard format for many download or streaming music portals on the Internet. Apple's iTunes shop by contrast works with AAC, and that move is not without consequences.
"AAC became dominant among Apple users and is already more widely distributed than MP3," says Christine Tantschinez, test editor at Stuttgart-based Audio magazine. MP3 will not completely disappear, she thinks, but playback devices will be able to handle more and more formats in the future. "In terms of sound and efficiency, AAC has the better future prospects, though."
To avoid distortions, music should not be transcoded into the MP3 format at rates of less than 192 kbit/s. "You can even consider data rates of 256 kbit/s or more, although almost very little difference can be heard in that range," is the recommendation from the Fraunhofer-Institute for Integrated Circuitry in Erlangen. To discourage users from trying to wring out savings on the wrong end of the spectrum, however, the free codecs Musepack (MPC) and Ogg Vorbis only start at around 160 kbit/s.
Lossless codecs are the choice for those who refuse to tamper with the music. They work by compressing the existing data into itself. This retains the original sound but can cut data size by half, Stoll says. In principal the codecs differ from one another only in terms of compression and decompression speeds. The open source Free Lossless Audio Codec (FLAC) has a slight edge in that department.