The product of constants is a constant: a bit rate question.

Discussion in 'Music Streamers' started by jdutko, Feb 5, 2014.

  1. jdutko

    jdutko
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    Hi Folks,

    I have a simple bit rate question regarding FLAC files. (I have been looking at the bit rate values of various FLAC files using JRiver and MediaMonkey.)

    If bit rate is the product of constants why do FLAC files have unique bit rates? That is, all FLAC files ripped with a given bit depth, sample rate, and channel number, all constants, should share an identical value for bit rate. For example, FLAC files ripped at CD quality should all display an identical bit rate, 1,411.2 kbps (bit depth x sample rate x # of channels; 16 x 44100 x 2).

    What am I missing here? Are these average bit rates? Is it connected to compression?

    Thanks for any help with this question!
     
  2. Cebolla

    Cebolla
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    Since FLAC is a lossless format any difference between its quoted bit rate and that of its original PCM source is entirely due to (lossless) compression. Not sure why JRiver & MediaMonkey bother to give this value if they don't also say what the bit rate of the FLAC file's PCM content is, which is probably more useful to the user. Having said that presumably you're told the file's bit depth & sample rate, so you could always work it out for yourself, if bit rate is your thing!
     
  3. jdutko

    jdutko
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    Thanks Cebolla!

    Sure, its easy enough to calculate the bit rate because the bit depth, sample rate, and stereo channel are listed, but why not just include the bit rate too?

    Still, there is something not obvious about how the "compression bit rate" is determined. Of course I am too uninformed about the technical aspects of digital sampling to justify this question; nevertheless, bit rate is related to bit depth and sample rate and does not include file size, so how can its value be altered when considering compression? Why would compression/decompression change the bit rate?

    I guess I'm getting a bit too psyched about bit rates!
     
  4. amcluesent

    amcluesent
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    Last edited: Feb 6, 2014
  5. jdutko

    jdutko
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