Are You Interested in the iPad Mini?

Ogg is a platform-independent copyright-free media container file format, analogous to QuickTime .mov or Windows Media .wma / .wmv files. Container file formats are not codecs in and of themselves. A container file format contains one or more streams which are encoded by a codec.

Vorbis is the “lossy” audio codec for the .Ogg file format. It uses much newer and better technology than .MP3, and better even than the improved .MP3pro, .MP4 AAC (Advanced Audio Codec), etc. This means that, compared to .MP3, you can get equal sound quality from a much smaller file (less than ½ the size or bitrate), or ½ the audibly perceivable sound degradation at the same file size or bitrate, or “split the difference” as you see fit.

FLAC (Free Lossless Audio Codec) is, as its name implies, lossless. This means that when it’s decompressed, every 1 and 0 is identical to what went into the codec at compression. While some other lossless codecs out there can produce slightly smaller files than FLAC, FLAC has the advantage of having consistently low CPU requirements for decompression no matter what compression settings were used. This means that it’s practical to store FLAC-encoded audio on a low-powered device, and only decompress it in real time as it’s playing, leaving it compressed in storage. FLAC is available both stand-alone and as an alternative codec for the Ogg container. FLAC can at best reduce a music file to somewhat over ½ its size, but that still means being able to hold more songs in limited memory and bandwidth without having to sacrifice even an iota of audio quality.

Speex is a very lossy codec for Ogg that is optimized for human speech (with no music, not even background music) and so would be great for telephony, dictation, lecture and court and police interview recording, etc. Speex can compress far more tightly than Vorbis (let alone .MP3) can while still maintaining audibly legible quality, but the presence of non-speech sounds in the mix can mess up the results. Vorbis, of course, compresses much more tightly than FLAC (or other lossless codecs).

Theora is an Ogg video codec that’s based on the formerly proprietary but now open-source On2 VP3 codec. It’s not as good as H.264, but is about on the level of H.263.

Ogg codecs are available (usually for free) for all major computer platforms and many portable devices. The Sansa and many other non-Apple portable media players come with Ogg Vorbis support built-in, and many others (including Apple) can download support for it.

A big thing about Ogg and all its codecs is that they are patent-free and licensing-free. The Motion Picture Experts Group (MPEG) codecs are all encumbered with patents and licensing fees, though they have loosened them up in recent years (partly due to the threat of competition from Ogg).

Anti-aliasing is a filtering process that does just what blurring filters do in, say, Photoshop. It’s not true blurring in the sense of making a lens go out of focus. It works by mixing the colors of adjacent pixels to form intermediate shades to try to hide the pixels from the human eye.

True anti-aliasing works by rendering line art (including outline text generated from outline font formats such as OpenType) and 3D objects to a multiple of the destination resolution, then sampling it down to the destination resolution with filtering to determine the amount by which to mix the colors for each edge pixel.

For instance, for 2× antialiasing, an object that will wind up being 100 pixels square would need to be rendered to a 200×200 raster buffer in memory somewhere, and from there two intermediate shades can be determined, for a total of four (full foreground, two-thirds foreground and one-third background, one-third foreground and two-thirds background, and full background). 4× anti-aliasing would require rendering to a 400×400 raster buffer but allow twice the total number of shades and thrice the intermediate shades (eight total, six intermediate). And so on.

You’re talking to someone who used to do manual pixel-by-pixel anti-aliasing of graphics on the Commodore 64 (tricky indeed with its fixed 16-color palette).

The “Retina” Display isn’t true retina-level even on the iPhone 4 and iPod Touch, let alone the Third Generation iPad, at least for people with 20/20 or better eyesight. But once they get to true retina quality, anti-aliasing would be no longer needed.