HDTV Magazine
Welcome, Anonymous  •  Sign In  •  Register  •  Help

Today’s Show:

Episode 541 is packed with information, from a CNet discussion on their favorite 3 (budget) receivers to the new STRIVA wi-fi headphones from Koss. Mixed in there is a list from Electronic House with 10 very unique remote controls that are sure to start as many conversations as movies in your home theater.

Home Theater Terms

  • Throw Ratio - When buying a projector, one of the key measurements you must know before you pay is the projector’s throw ratio.  The term throw by itself is the distance from the projector lens to the center of the screen.  The throw ratio is that throw distance to the screen divided by the width of the projected image, or essentially the width of screen it will support.  Since it is a ratio, there are no units associated with it; you can use feet, inches, meters, miles, whatever you like. Bottom line, the throw distance will narrow down which projectors are right for your room.  If you want to have a 200 inch screen, the projector will need to be able to do that from wherever you plan to mount it.  If you can only accommodate an 80 inch screen because of the wall space or room layout, you need to factor that in as well.  Because of zoom lenses, most projectors have a throw ratio range.  As long as your throw distance and desired screen size fall in that range, you’re all set.
  • Bitstream - Technically a bitstream is no more than digital information expressed in binary form (0’s and 1’s) moving from one device to another.  But when we use the term in a home theater context, we’re typically referring to a specific kind of information – namely audio information – moving from a source device, such as a blu-ray player, to an audio processing device, such as a standard AV receiver.  Audio in the bitstream state hasn’t been decoded yet; it is still in its encoded form: Dolby Digital, DTS, etc.  When the bitstream arrives at the receiver, the receiver is responsible for decoding it, converting it to analog and sending it to the speakers.  In cases where the receiver is incapable of decoding a particular audio format, the source device can decode it and instead of sending the bitstream, send the decoded audio as linear PCM.
  • Luminance - The part of a video stream that determines the brightness, or the black and white component, of the picture or video on screen.  The luminance value produces shades of grey that match brightness levels perceptible to the human eye.  In an analog component video cable the luminance value is kept separate from the color values, or chrominance, to produce a more pristine image.  Luminance values are carried on the green or ‘Y’ cable while the chrominance values are carried on the other two cables, the red (Pr) and blue (Pb) cables.  For analog video, component cables are typically considered the best compromise between compression and quality.  In digital video signals, such as HDMI and DVI, the video is in a digital format, so the luminance portion of the stream is simply encoded as part of the color values.


Download Episode #541

Posted by The HT Guys, July 26, 2012 11:53 PM

About The HT Guys

The HT Guys, Ara Derderian and Braden Russell, are Engineers who formerly worked for the Advanced Digital Systems Group (ADSG) of Sony Pictures Entertainment. ADSG was the R&D unit of the sound department producing products for movie theaters and movie studios.

Two of the products they worked on include the DCP-1000 and DADR-5000. The DCP is a digital cinema processor used in movie theaters around the world. The DADR-5000 is a disk-based audio dubber used on Hollywood sound stages.

ADSG was awarded a Technical Academy Award by the Academy of Motion Picture Arts and Sciences in 2000 for the development of the DADR-5000. Ara holds three patents for his development work in Digital Cinema and Digital Audio Recording.

Every week they put together a podcast about High Definition TV and Home Theater. Each episode brings news from the A/V world, helpful product reviews and insights and help in demystifying and simplifying HDTV and home theater.