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Thread: PCM wav file header info misread?

  1. #1

    Join Date
    Sep 2002
    Posts
    14

    PCM wav file header info misread?

    Hello there:

    It's been a long time since I was last here, but when nothing is out of the ordinary I need no help.....until now.....

    I have a question on how the getpopupinfo exe reads a wav file,

    recently I have begun to collect hi res audio albums, these are all in 24bit & the majority are 96khz sampling rate.

    any 16bit/44khz wav file is read by *popupinfo* as being 100% & uncompressed (1to1),

    here's where the oddity begins..........any wav file that is 48khz or 96khz is read as being 150% in size & .6 to 1 compression.

    Why is this happening? why can't dbpoweramp read any of these files as being 100% in size?

    This is having a negative effect on the encoded to mp3 file that I create insomuch as the file being compressed to 320 constant or variable is being compressed at 7 to 1 down to the same size that a smaller 44khz file would be compressed to at 4 to 1. If I take two files of the same piece of music, one being 44khz & the second a 48khz file both will compress to the smaller 44khz size. I'm assuming that the 48 khz file is seeing more information being tossed to compress it.

    I don't understand where the file is being misread by poweramp causing the incorrect compression size.

    here's a screenshot of what I am referring to.....





  2. #2
    Administrator
    Join Date
    Apr 2002
    Posts
    38,926

    Re: PCM wav file header info misread?

    Your version of dBpoweramp looks very very old. It is likely this bug has been fixed long ago. I have just tested a 96KHz 2 channel 24 bit file and it shows 100%

  3. #3

    Join Date
    Sep 2002
    Posts
    14

    Re: PCM wav file header info misread?

    That's true,

    I still have version 10, continue to use it as it was the last version that seemed to accept an update of the lame.dll encoder without causing some stir when encoding and also it was (to my knowledge) the last version that allowed more freedom to the user when selecting individual encoding quality parameters apart from the defaults.

    Version 13 is also here, I really never used it (it was my brothers), I can't send you a screenshot of what the version 13 popupinfo exe sees when a wav is encoded to mp3, the *menu* stays on the screen for as long as the cursor is over the file, move off the file to activate my screenshot grabber & the menu disappears....lol.....the popup exe displays a 24 bitrate seemingly being downsampled to 16 from the original 24 when going thru the encoding process.

    also........when one goes into the configuration window for the encoder one cannot alter the frequency off 44khz (cd) & the bitrate from 1411 altho there are drop down tabs that appear to make alterations for either.


    Steve

  4. #4

    Join Date
    Sep 2002
    Posts
    14

    Re: PCM wav file header info misread?

    well, my question has been answered,

    over at Sourceforge one the open source programmers for Lame explained to me that which I was totally unaware of,

    no mp3 encoder has the ability to encode a 24bitdepth wav file at 24bits. The encoder will first downsample that 24bits to 16bits then encode to mp3. That he said is why you're seeing such a large compression of a 24bit/48khz wav file that is physically larger than it's 16bit/44khz counterpart. The version of poweramp I still use has nothing to do with the way the file is being read or processed.

    I did not know that.

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