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Advice on dealing with huge wav files.

Discussion in 'Recording' started by eTetoPR, Oct 10, 2007.

  1. eTetoPR

    eTetoPR Guest

    Hi,
    I use a Fostex MR-8HD as a court reporter, meaning for recording mostly conversations. I like the multichannel thing, is ideal when lawyers interrupt eachother.
    Anyway, I'm recording into 3 to 4 channels at once and the files are huge, up to 500mb each. It would be ideal for me to be able to compress and combine these files while preserving the multichannel thing. What software do I need to do this?

    Thanks in advance and please excuse my English.
     
  2. casper

    casper Guest

    I would have a look at Audacity
    http://audacity.sourceforge.net/about/features

    If you encode each track as an MP3 file then you can import each track to Audacity. Im not sure how the tracks will lineup once in audacity. You need to folow the instruction to load the Lame Encoder for audacity. You will have to use windows media player or some other player/converter that can convert your tracks from wav to mp3. The lowest resolution you may want to compress to is 128Kbs.

    Audacity is free so you can't lose in trying it.

    Good Luck!
     
  3. RemyRAD

    RemyRAD Well-Known Member

    You could make your wave files, much smaller by changing your settings to 22.5kHz or even 11kHz sampling frequency at 16 bit. You don't need response to 20kHz for spoken word purposes. 22.5kHz will get you out to 10kHz bandpass and 11kHz sampling will get you out to 5.5kHz bandpass. With each change in sample rate, the size will half. It will also still be uncompressed which might be important for legal purposes? As compared to a compressed format, such as MP3, which has had data removed! So I WOULDN'T recommend MP3 for court reporting purposes especially with its artifacts. And of course, you don't need to be cutting stereo tracks. Mono tracks are what you should be cutting. Huge files? Honey, you ain't seen long huge wave files. Just wait until you start adding video from multiple camera sources of six-hour music festivals. Huge as in the moon compared to Jupiter!

    Less huge by 50 pounds
    Ms. Remy Ann David
     
  4. eTetoPR

    eTetoPR Guest

    Thanks for the reply casper and RemyRAD.
    I will check that link, casper. It is important that the tracks line up. The benefilt of multitrack is that when people interrupt eachother, the person making the transcription has the ability to isolate what is being said.
    MP3 is a choice, no problem as long as I'm certain the words still there. The settings RemyRAD tell me about will certainly help. I will go over that with the manual. My problem is ignorance, this is highly technical and I know nothing :)
    One question, does MP3 soupport multitracks in one file?
    Thanks both.
     
  5. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    For most of us 500 mb files are nothing. A CD can have 700 mb and as RemyRAD pointed out if you get in to live concert recording the 2GB limit of windows is way to low.

    Best of luck! If you follow RemyRAD's suggestions I am sure you will have no problems. We do a lot of forensic work and I can tell you from experience that MP3s are tough to work with. I would stay away from them at all costs. Sometimes they are so bad that it is hard to make out the words and in your business that may not be very good.
     
  6. Cucco

    Cucco Distinguished Member

    This is a very important consideration.

    I do a LOT of work with the FBI/CIA and "other" government agencies and any forensic audio/video we work with MUST not be compressed. Any compression algorithm is deemed to "alter" the original signal and many jurisdictions will no longer allow it as admissable evidence.

    Since you mention that your english isn't strong (which, for what it's worth, I find to be better than most native english speaking americans!), I'm assuming you're not having to deal with American laws and regulations, but if you're ever concerned with extradition with evidence from court hearings, you might want to stay uncompressed.

    Cheers -

    Jeremy
     
  7. eTetoPR

    eTetoPR Guest

    How do you change the file settings?
    Can't find how to change it in the recording equipment (MR-8HD), and using the Audacity program it changed the size from 376 MB to 1.41 GB, obviously I'm doing something very wrong. This is what I did, open file, set Sample format feom 32-Bit Float to 16-Bit, then Set Rate from 44100 Hz to 11025 Hz.
    I think I should be messing with the Bit Rate (705kbps, Is that kilobites per second?, if so WOW), but I don't see how.

    I doubt these files will be used as evidence, they use my transcript. In case they challenge the transcript and want to listen to the audio they'll have to liten to whatever I have, and it has to be 90 days from the day of recording. No problem to keep those wavs that long.

    Thanks for the replies.
     

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