Gizmodo: compression

Comcast Compressing HDTV Signals to Fit Three Shows into Two Shows' Bandwidth

Jason Chen — Mon, 31 Mar 2008 14:45:00 EDT

Comcast has begun compressing HDTV shows in order to deliver more HD channels to you while using the same amount of bandwidth. They didn't use to do this before, but now, when compared to Verizon FiOS, the channels are grainy and blocky and full of artifacts—a result of shoving three channels into a space where only two previously occupied. A guy at AVSForum measured how the new bitrate stacks up against Verizon.

DVice has a side-by-side of the FiOS vs. Comcast comparison as well, and things look pretty damn ugly.

The forum poster says that the compression isn't too horrible with still images, but gets really bad when stuff moves around.

The greatest differences are seen with movement. With slow movement on Comcast, the first thing you notice is added noise and a softer image, as fine detail is filtered from the picture signal. The greater the rate of movement, the more detail you lose and the more noise you see. With intense movement, you see more blocking and skipped frames. In VideoRedo, I noticed that a number of frames in the FiOS signal simply did not exist in the Comcast signal during motion intensive scenes. This may be responsible for the stutter and excessive motion blur seen with some video sequences on Comcast.
To Comcast's credit, I saw little to no difference on movie channels such as HBO, Cinemax, and Starz. I did see some blurring and reduced detail during fast movement on Starz, but the recordings from Cinemax and HBO were virtually identical, even on action movies such as 300 and Gladiator. When there was blocking on the Comcast feed of Cinemax, that blocking was also on the FiOS feed.

[AVSforum via DVice]

ADS InstantVideo To-Go Accelerates iPod and PSP Video Encoding

Charlie White — Mon, 20 Nov 2006 08:43:11 EST

ADS announced InstantVideo To-Go, a nifty little $79.95 widget that supercharges compression of video into that oh-so-sweet H.264 format. The company calls it the first hardware-based H.264 conversion device for PCs. This little USB key is a video transfer accelerator that lets you convert any video into that butta-smooth format specifically for playback on an iPod or PSP, and lets you accomplish that feat five times faster than real time.

So what this means is you can take a DVD's worth of video and crunch it down for 320x240 playback on your iPod or PSP in 20 minutes, something that can take five hours to do with software encoding. And this baby can do that with a slew of media formats, too, including MP4, MP3, AVI, WMV, MOV, RM, JPG, and TIFF. Yeah, ADS. This we gotta try. – Charlie White

Products Page [ADS Tech]

Apple Lossless On the Way to iTunes?

Charlie White — Fri, 23 Jun 2006 13:22:49 EDT

Although some of us here at Gizmodo are near-deaf from spending way too much time in musical environments exceeding 130dB, we're still happy to hear the rumor that Apple will soon distribute tracks compressed in its Apple Lossless compression format on the iTunes Music Store.

Audiophiles rejoice, because those rumors just might be true. In a private release of iTunes Producer 1.4, the application used by record companies to compress music for submission to the iTunes music store, the software is newly capable of encoding music using the Apple Lossless format. This is a really good thing, because heck, even with our addled ears, we don't much like the sound of Apple's Advanced Audio Coding (AAC) format. – Charlie White

Apple Lossless format coming to iTMS? [Apple Insider]