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Thread: encoding problem.

  1. #1

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    encoding problem.

    I have a 24bit 48khz wav file (bitrate=2304kbps).

    When I convert to 24/48 flac the file size is 26MB Windows shows it as 24/28 with bitrate is 836kbps (way too low for 24/48)
    Converting to 16/48 gives a file size 25.8MB and bitrate 831kbps.

    The same file I encoded to 24/48 a couple of years ago gave a flac file of 50MB and 1604kbps.

    What's going wrong?

  2. #2

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    Re: encoding problem.

    update - if I extract file as ALAC I get expected file size/bitrate
    If I then transcode that to FLAC it reduces size and bitrate as before

  3. #3
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    Re: encoding problem.

    It is possible your 24 bit files are really 16 bit which are padded to 24 bit, and the encoder is making use of that to reduce the compression.

    If you are using Windows, install the 'Calculate Audio CRC' utility codec:

    https://www.dbpoweramp.com/codec-central-utility.htm

    Then convert the original untouched wave file and the flac file both to this encoder, if the resulting CRC numbers match, then the audio is identical and it does not really matter what bit rate it is.

  4. #4

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    Re: encoding problem.

    Hi Spoon,
    Apologies for the delay in getting back to this thread - yes it is still a problem.
    I'm trying to convert some files from a DVD to go on my NAS drive so I can stream them in high quality - I extract these with DVD Audio Extractor (licensed)
    When this program displays the DVD contents it shows the various chapters and tracks within each and what audio configurations are available
    For the one in question it shows various audio configs - they are ALL 24/48, one stereo (the one I want) and two different 5.1
    If I extract to WAV I get files with a bitrate of 2304kbps. When I convert to ALAC I get files with bitrates between 1631kbps and 1946kbps
    If I convert to FLAC the bitrate and file size is around half that of the ALAC and bitrate is more in line with 16 bit files (798-1012kbps)
    Now the odd thing with this DVD is there are 5 extra tracks not on the album, they show as an extra chapter (24/48 stereo) and these encode to flac with the expected results bitrates and files size similar to the ALAC.

  5. #5

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    Re: encoding problem.

    I have just re-encoded original wav file to various lossless formats
    Here's a screen shot of the results Clipboard Image.jpg

  6. #6
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    Re: encoding problem.

    You did not run the test I asked you to do (Calculate audio crc), so I cannot comment any further until that test is completed/

  7. #7

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    Re: encoding problem.

    Apologies

    B6B59C76 E:\_DVD Audio Extractor\test\Title2 - Chapter 01.m4a
    B6B59C76 E:\_DVD Audio Extractor\test\Title2 - Chapter 01 (24bit).flac
    6328B918 E:\_DVD Audio Extractor\test\Title2 - Chapter 01 (16bit).flac
    B6B59C76 E:\_DVD Audio Extractor\test\Title2 - Chapter 01.ape
    B6B59C76 E:\_DVD Audio Extractor\test\Title2 - Chapter 01.wav

  8. #8
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    Re: encoding problem.

    As you can see, the flac file has the same data exactly as the other files, it is just FLAC is finding ways to increase the compression on those files, they all decompress exactly the same which is what counts.

    It is like using ZIP to compress word documents, if one document was 1/10th of the size and all other documents only 1/2 of the size, would it matter if they all unzip correctly to the original?

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