Glossary of Technology Terminology?

itschris

itschris

Moderator
Is there one in our community? I"m still having some difficulty grasping certian things. Bitstreaming for example. What is it? Spdif? For Blu-Ray I thought everything goes through an HDMI cable... so is that including the bitstream and video? I"m just not sure how all these things relate and it's gettting confusing as I hone in on all this stuff.

For instance, with HTPC's the audio cars have Dolby 5.1 or 7.1 output. Does that mean the card is doing the actually surround sound processing or is it just sending the signal to the receiver or pre/pro to get processed? Are these sort of fundamental questions answered anywhere?

I don't want bug everyone with questions about stuff I should already know.
 
M

MDS

Audioholic Spartan
Digital audio formats are a bunch of numbers. A sequence of those numbers transported to somewhere else is therefore a stream of bits ('bitstream'). The bits are transported one after another, like a single file line.

There are raw formats like PCM where each number represents the amplitude of the original analog signal at various points in time (eg. 16 bit / 44.1 kHz PCM on a CD means there are 44,100 16 bit numbers for every second of the audio; that means to digitize the original analog signal it was 'examined' 44,100 times per second).

Other formats compress the raw data into another form to save space or to include more discrete channels of information in the same available space. Those are still transported one bit at a time but need additional processing ('decoding') to turn it back into the raw PCM. So a DD/DTS or other bitstream transported to your receiver requires the receiver to decode it to a raw sequence of numbers which can then be converted to analog and amplified.

S/PDIF is data format and communication protocol for transporting digital audio from a sender to a receiver (or source to sink, if you will). If you are using coax or optical digital connections from say a dvd player to an AV receiver you are using s/pdif. HDMI is the same principle but can carry audio, video, control signals, copy protection data, etc all at the same time.


Re computer sound cards: There are some cards that include the ability to output a digital signal only so that you could send it to a receiver for decoding 5.1 but many simply include the processor, either in the hardware or as part of the software (driver), to do the decoding and output each channel as an analog signal after decoding.
 
F

fmw

Audioholic Ninja
Is there one in our community? I"m still having some difficulty grasping certian things. Bitstreaming for example. What is it? Spdif? For Blu-Ray I thought everything goes through an HDMI cable... so is that including the bitstream and video? I"m just not sure how all these things relate and it's gettting confusing as I hone in on all this stuff.

For instance, with HTPC's the audio cars have Dolby 5.1 or 7.1 output. Does that mean the card is doing the actually surround sound processing or is it just sending the signal to the receiver or pre/pro to get processed? Are these sort of fundamental questions answered anywhere?

I don't want bug everyone with questions about stuff I should already know.
Wikipedia has a lot of definitions and might be a good place to look.
 
itschris

itschris

Moderator
Thanks guys. So... s/pdif or HDMI carry the bitstream... got it. I would assume in building an HTPC... you wouldn't want the audio card doing the decoding. Why would we even spend the big dollars on high end receivers and pre-pros at that point correct?
 
newsletter

  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top