William Stanek here, continuing with the in-depth look at e-readers and e-books. In my earlier blog entries, I introduced EPDs, discussed how the technology works, and delved briefly into ways they're being used. Now, I'm examining the Sony Reader as a case study in how e-readers work. My hope is that if you are better informed, you can decide whether an e-reader is right for you. And who knows, an e-reader may just replace your MP3 player as your favorite device.
So back to the Sony Reader discussion of the PRS 505 and the PRS-700...
In addition to being able to display tables, charts, graphs and figures in documents, the Sony PRS-505 and the PRS-700 can be used to display graphics as either stand-alone images or slideshows. The supported formats are:
Bitmap This file format is used with screen captures and other bitmapped files. Related files end with the .bmp extension.
JPEG The Joint Pictures Expert Group (JPEG) format supports high-resolution graphics and compression. Compression reduces the size of JPEG files. However, the higher the compression the more image data that is lost and the lower the quality. Related files end with the .jpg or .jpeg extension.
GIF The Graphics Interchange File (GIF) format is best used with low resolution to moderate resolution graphics as well as with graphics that have lots of text. Related files end with the .gif extension. By reducing the colors in the color palette and using options such as dithering, GIF images can be squeezed into smaller size files.
PNG The Portable Network Graphics (PNG) format supports lossless compression ensuring images can be squeezed into smaller files without reducing quality. Related files end with the .png extension.
These graphic formats are the popular formats used on the World Wide Web. GIF is a good format to use with standard graphics or graphics containing text. JPEG is a good format to use for high-resolution graphics and pictures. PNG is a good format to use to squeeze high-quality graphics into smaller size files. The least efficient of these file formats is BMP. Typically BMP files are much larger than the same files converted to GIF, JPEG, or PNG.
Audio playback is a great extra feature of the reader. You can play unsecured audio files in the following formats:
MP3 The MPEG Layer 3 audio encoding (MP3) format is a quality audio format. Related files end with the .mp3 extension. The reader supports MP3 files with a bit rate of 32 kilobits-per-second (kbps) to 320 kbps and a sampling frequency of 22.05 kilohertz (kHz) or 44.1 kHz.
AAC The Advanced Audio Coding (AAC) format is a quality audio format. Related files end with the .mp4, .m4a, .mov or .qt file extension. The reader supports AAC files with a bit rate of 40 kbps to 320 kbps and a sampling frequency of 24.0 kHz, 44.1 kHz or 48.0 kHz.
As an interesting aside, AAC files are also referred to as MP4 files. Although MP3 is the audio format most everyone recognizes, AAC actually is nearly as widely used as AAC is the default format for the Apple iPod. AAC is one of several audio coding formats defined by the International Standards Organization (ISO) for MPEG. AAC was first specified as MPEG-2 AAC, and then enhanced and extended within MPEG-4. Apple's popular iTunes music service uses the AAC format.
AAC uses a perceptual coding technique to compress digital audio files. AAC is similar to MP3, but offers a number of advantages designed to improve audio quality, including higher-efficiency compression and better handling of audio frequencies above 16 kHz. The improved efficiency of AAC files makes AAC a better choice than MP3.
With bits rates, the higher the bit rate, the higher the audio quality and the larger the file size. Bit rates on the low end of the scale are suitable for voice-only recordings, such as spoken-word audio books while higher bits rates are better suited to music. For example, a bit rate of 128 kbps provide fair quality for music while a bit rate of 192 kbps provides good quality for music.
As an interesting aside, the sampling frequency determines the number of times per second the music waveforms are captured digitally. The higher the sampling frequency, the higher the quality and the larger the file size. A sampling frequency of 44.1 kHz provides CD quality audio. A sampling frequency of 48.0 kHz provides studio quality audio.
With MP3, a 60-minute audio CD encoded at 128 kbps uses about 57 MB while the same CD encoded at 192 kbps uses about 86 MB. When converting audio, don't choose a bit rate or sampling frequency that is higher than the bit rate or sampling frequency used to store the audio originally. You'll waste space and won't get fidelity improvements.
Because audio playback is separate from the display features for reading, you can play audio while you display pages of a book. On the bottom of the reader, you'll find a headphone jack that you use to connect headphones and a two-way volume button for adjusting the volume up or down when you are playing audio through headphones.
Cool tip: When you are playing audio, you can mute the sound by pressing and holding either edge of the volume button. To restore the sound, simply press the volume button again in either direction.
Thank you for reading! Hope you'll take a look at my new book Windows 7: The Definitive Guide.
William R. Stanek
williamstanek at aol dot com