I wondered for a long time about the various bit-rates required for different types of "streaming technologies" (which just means "play it while you download it"). It's never been really clear to me which ones put data through at what speed, and what that translates to in terms of "How fast a connection do I need to listen to this or watch that?"

I put together the info on this page from a few sources, but mostly Wikipedia. Great resource that Wikipedia. The last bit, Peripherals, comes from this page, a case of what is possibly the highest usefulness-to-everybody/degree-of-complexity ratio of any page in the universe. Note the handy comparison of bytes to bits in that table as well. While marketers regularly use these terms interchangeably, they're very much not.

For now, there's two imperative things to understand: local data versus remote data. To understand the difference between the two, it's important to understand/remember how "non-computer" people see things. It's part of the reason that this "in the cloud" thing is a little more hype than substance. Hopefully I can shed a little light on that too.

For the initiated it may seem incredibly elementary, but in fact, the initiated are inerred to the more natural and intuitive understanding that your grandmother might have, i.e. there is no difference between local and remote data. As far as she's concerned, the screen is here, the computer is here, the AOL is here, the Hulu where she watches her stories is all right here.

You are always here

When i was a kid, my dad used to tease us with the "We're never gonna get there, 'cause even when you do, you're still here." As a 6 year old, the humor of the comment was lost on me, rather it was my dad being himself.  It is however, apropos here, because it's about the best way i know for people to get a handle on the difference between remote data and local data. It's the same reason it's stupid for a company to tell you you can't copy their product but you can watch it; you can't do either one without the other no matter how much anyone wishes otherwise.

When you have a movie on a DVD or your hard drive or on Netflix or on iTunes or Hulu or anywhere else you might find a movie to watch, you copy it to your machine for processing. The process of viewing is EXACTLY the same in all cases. The only differences are

1. How you get it into your machine for processing.
2. What your machine does with it after processing.

Once your machine has the data ready for processing, it's been read from a temporary file on the local hard drive, which is ostensibly the fastest place to keep data. There is an intermediate step where the data is "in RAM" - meaning that it's stored in the machine's memory. Memory, or "RAM" is considerably faster than a hard drive, but far more precious. Most machines have several hundred times as much hard drive space as memory space, so the machine uses the hard drive to store things before processing them using RAM.

This article contains information about how data moves once it's local. I don't think i'll go into how it travels inside your machine, but this should give you a basic comparison of the speed requirements of various media formats, as well as the speed capabilities of various data-transfer formats. I italicized the most common connections for us home users.

Stuff

Audio (MP3)

• 32 kbit/s – MW (AM) quality
• 96 kbit/s – FM quality - This is questionable since FM broadcast is transmitted in analog 30hz-15khz...Similarly one cannot compare directly an LP record to CD using kbit/s.
• 128–160 kbit/s – Standard Bitrate quality; difference can sometimes be obvious (e.g. lack of low frequency quality and high frequency "swashy" effects)
  
• 192 kbit/s – DAB (Digital Audio Broadcasting) quality.
• 224–320 kbit/s – VBR to highest MP3 quality

Other audio

• 800 bit/s – minimum necessary for recognizable speech (using special-purpose FS-1015 speech codecs)
• 8 kbit/s – telephone quality (using speech codecs)
• 32-500 kbit/s -- lossy audio as used in Ogg Vorbis
• 500 kbit/s–1,411kbit/s – lossless audio as used in formats such as Free Lossless Audio Codec, WavPack or Monkey's Audio
• 1,411.2 kbit/s – PCM sound format of Compact Disc Digital Audio

Video

• 16 kbit/s – videophone quality (minimum necessary for a consumer-acceptable "talking head" picture using various video compression schemes)
• 128 – 384 kbit/s – business-oriented videoconferencing quality using video compression
• 1.25 Mbit/s – VCD quality (with bit-rate reduction from MPEG-1 video compression)
  
• 1374 kbit/s – VCD (Video CD) – audio and video streams multiplexed in an MPEG-PS
• 3.5 Mbit/s typ - Standard-definition television quality (with bit-rate reduction from MPEG-2 compression)
• 5 Mbit/s typ – DVD quality (with bit-rate reduction from MPEG-2 compression)
• 8 to 15 Mbit/s typ – HDTV quality (with bit-rate reduction from MPEG-4 AVC compression)
• 29.4 Mbit/s max – HD DVD
• 40 Mbit/s max – Blu-ray Disc

Peripheral