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PCM 48 KHz to WAV

Discussion in 'Audio' started by Amstel, Feb 19, 2003.

  1. Amstel

    Amstel Member

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    I want to make audio CD's (to play in my car) from a couple of Music DVD's.

    From the Bruce Springsteen DVD, I ripped the AC3 and PCM tracks with DVDDecrypter. Normally I use HeadAC3he for decoding AC3 to WAV, but in this case I think it's better to use the PCM track.

    But how to convert the 48 KHz (raw?) PCM track to 44.1 KHz WAV???????????
     
  2. tigre

    tigre Moderator Staff Member

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    Right - use the PCM track.

    Some possibilites for converting:
    1. You could use Cool Edit, it can read RAW files.

    2. I did this before with wav, not with raw files, so I'll tell you how: With smart Ripper you can demux the pcm track to a 48kHz wav file and convert it to 44.1kHz using
    - SSRC, available at http://shibatch.sourceforge.net/ or
    - foobar2000's resampling + diskwriting features: http://foobar2000.hydrogenaudio.org/
     
    Last edited: Feb 19, 2003
  3. cd-rw.org

    cd-rw.org Active member

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    Good answer tigre. I personally would go for SSRC.

    User 'tigre' has been promoted from newbie to member. Reason: A very good response to a question.
     
  4. Amstel

    Amstel Member

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    Thank you tigre for your response.

    I installed Cool Edit Pro 2.0 and indeed it could read the raw PCM tracks. But this program can also do a batch conversion from 48 KHz raw PCM to 44.1 KHz WAV, so SRC is included. Thats cool!

    I have to say that I don't understand how to use the command line program SSRC. If somebody can write an example for me, I would be grateful.

    On the other hand, do you expect a quality difference between SSRC and the SRC of Cool Edit?
    If there is only a AC3 track on a music DVD, is HeadAC3he then the program to use? Do I have to mind the settings, apart from 44.1 KHz?
     
  5. Amstel

    Amstel Member

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    Ok I understand already how to use SSCR technically spoken. If somebody has suggestions for settings, please respond.

    Meanwhile I made 3 rips from the same song (The River, Bruce Springsteen Live in New York City) to a 44.1 KHz WAV file.

    The first one I made from the AC3 track with HeadAC3he, the second one from the raw 48 KHz PCM file with Cool Edit Pro (in one batch from 48 KHz PCM to 44.1 KHz WAV).
    For the third file, I made first a 48 KHz WAV file from the raw PCM file with Cool Edit Pro and then used SSRC for the sampling rate conversion.

    I burned the 3 files on a CDRW and listened. The PCM mix is slighty different with the stereo extracted from the AC3 (I think so). But they are all acceptable quality tracks. I have to experiment more I guess.

    So far, because of the simplicity, I prefer to convert the PCM track at once with Cool Edit Pro.

    Any comments, questions or reactions??
     
  6. tigre

    tigre Moderator Staff Member

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    1. Probably the PCM track hasn't suffered lossy compression before mastering, while the AC3 track *IS* lossy compressed. Additionally the stereo image of the 2 Channel PCM track should be superior to a downmix from surround.

    2. You can't get better resampling quality on 16 bit resolution than CEP's. If you have CEP there's no need to use SSRC.

    3. About CEP's settings:
    Pre/Post Filter "on"
    Quality: anything >600
    Dither: enabled
    p.d.f: Triangular
    Noise Shaping (44.1kHz)
    Dither Depth (bits) 0.4

    FYI: Dither=Add low level random noise to avoid distortion caused by quantisation. I did some tests with CEP to find out which settings are good. The settings you find above avoided all distortion and added least audible noise.
     
  7. Amstel

    Amstel Member

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    Thank you again tigre. I got some understanding how to convert from PCM tracks.

    With CEP I cann't use the "dither field" when I stay in 16 bits resolution. I can go to 8 bits resolution, change the field and go back to 16 bits.

    What is your procedure for converting AC3 tracks to 44.1 KHz WAV files?

     
  8. tigre

    tigre Moderator Staff Member

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    Sorry - I forgot to mention some (important) details about my procedure:

    1. Open 48kHz/16bit .wav / .raw file with CEP
    2. Change resolution to 32 bit
    3. Resample+Dither to 44.1kHz/16bit
    4. Save.
     
  9. Amstel

    Amstel Member

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    Thank you again tigre. After a day of work I continue the fun.

    I think I get your point, going to 32 bit all the calculations are done in a higher precision and as the last step you go back to 16 bit resolution.

    But how to do step 2, going to 32 bit resolution? Are you using the same CEP "Convert Sample Type" option, and choose going from 48 KHz 16 bit to 48 KHz 32 bit?
     
  10. tigre

    tigre Moderator Staff Member

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    Amstel: > Are you using the same CEP "Convert Sample Type" option, and choose going from 48 KHz 16 bit to 48 KHz 32 bit?

    Exactly.
     

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