Change Album Art; About Encoded Audio; Bitrates; Variable Bitrate - Nokia N91 User Manual

Change album art

1 Select a song.
2 Select Options
3 Select Options
4 Scroll through images from your Gallery, and select
Select:.
5 To restore the original album art, select

About encoded audio

Applications like Windows Media player and Nokia Audio
Manager encode audio files with codecs like WMA or MP3
to save storage space. The encoding is done by removing
those parts of the audio signal that are not audible or only
barely audible by human ear.
Regardless of the encoder and codec quality, the sound
quality of the resulting file is not as good as the original.
The basic codecs supported by this device are AAC, WMA,
and MP3. All of these have different variations.

Bitrates

When encoding audio, the quality of the resulting sound
depends on the sample rate and bit rate used for the encoding.
Sample rate is expressed as thousands of samples per
second (kHz), and for CD music the sample rate is fixed at
44.1 kHz. Bit rate is expressed as kilobits per second (kb/s).
The higher the bitrate, the better the sound quality.
26
> Album art.
> Change.
Restore
The required quality level may depend on your demands,
the headphones used, and the surrounding noise. For MP3s
a bitrate between 128 and 192 kb/s usually gives results
good enough for listening to pop music with your device.
WMA or AAC generally gives a similar result as MP3 with
one step lower bitrate (96-160 kb/s). Variations of AAC,
such as AAC+ and enhanced AAC+ (eAAC+) provide CD
quality audio at bitrates as low as 48 kb/s. Classical music
original.
and music with nuances usually require a higher bitrate
than basic pop music.
For speech or other sources where the quality of the sound
is less important than saving storage space, you can use
bitrates between 8 and 64 kb/s. At low bitrates WMA
or AAC generally gives better results than MP3.

Variable bitrate

Your device also supports variable bitrate (VBR). Variable
bitrate means that the bit rate of the encoding varies with
the complexity of the encoded material. When using VBR,
the encoding is optimized to preserve a constant audio
quality throughout the track, rather than losing quality
for complex music sections as with constant bitrate
(CBR) encoding.