Can I convert 2 channel analog audio to digital?

Discussion in 'High resolution audio' started by rjessa, Jan 13, 2006.

  1. rjessa

    rjessa Regular member

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    Once I edit my home made movies, I would like to convert the audio to a higher level, can I do that? Also are all of Digi8 & VHS movies with PCM audio?

    Thanks for any help I can get.
     
  2. djscoop

    djscoop Active member

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    when you capture your analog video tapes into your computer, you essentially are converting them to a digital audio format. as far as upping the quality, you can't really get anything better than the original sound from the tapes by upsampling the audio to a higher quality. In other words, when you are digitizing your tapes the audio is probably being recorded at 16 bit 44.1khz audio, which is the standard PCM format for cd-quality audio. but upsampling the quality once captured to say dvd-audio, which is 24 bit 96 khz, really won't make a difference, because the audio was originally digitized at CD quality, so you can't get anyting better than that. if they were originally digitized at a higher quality, then that would work, but that all depends on what program and hardware you are using to capture with, so you may not be able to record at anything higher. But for the quality of audio that's on VHS and Hi-8 tapes, the standard PCM CD-Quality audio is just fine. You don't need anything higer.
     
  3. wilkes

    wilkes Regular member

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    What djscoop is saying is almost, but not quite, correct.
    You are digitizing when you capture.
    As far as upping the quality goes, this depends on your target format.
    If you are talking DVD-Video, the Audio will have been captured at 16/48 resolution. The DVD-V specs will allow an encoded resolution of up to 24/96 for stereo files, but you should be aware not all players support the playback at full resolution, and will truncate to 48KHz, or decimate the bit depth down to 16 bit without dithering, causing truncation.

    If a final rate of 24/96 is really what you require - and you will get just as good from 24/48 IMHO - then you can convert the audio to 24/48 or 24/96, and any further processing you carry out will be at the increased resolution. Unless any extra processing is done, the process is pointless as all you will be doing is padding the original file with zeroes.

    For home made movies, I would really suggest that you follow djscoops advice, and leave well alone at 16/48 LPCM, and when you author the title - do NOT encode to Dolby Digital, but leave as LPCM.
    This will reduce your available bitrate for video files to (9.8 - 1.6) 8.2 megabits per second.
    If the target is a written disc, then you don't really want to encode video at a higher rate than 7 Mb/Sec, or some players may well choke on the bitrate as the reflectivity of written media is not nearly as good as a pressed disc and may cause errors the player cannot recover from.
     
  4. djscoop

    djscoop Active member

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    kudos wilkes, glad to see ya around again!
     

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