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  1. I hoping to get some help on capturing the audio tracks properly from mini DV tapes. My goal is just to confirm that the work flow I plan to us to archive my old tapes is preserving the original info as much as possible.

    Here is my situation:

    - I have a small number of old mini DV tapes that I am trying to capture to hard disk. The camera they were recorded on was lost, and I am not sure of the model number, but it was an early model Sony DCR-HCxx model. I am not certain what setting I used on this original camera with respect to audio format (12-bit or 16-bit). My guess is that I kept the default of 12-bit.

    I have now purchased a used Sony DCR-HC36 camera to capture the tapes. The tapes play on this camera, and I have been able to capture the video using DV Processor, Sony PlayMemories, and WinDV.

    My issue is that I seem to get different results based on which software I use, especially with respect to the audio tracks. I have attached the output files from MediaInfo for the avi files produced by the Sony software and Enosoft DV Processor. (WinDV produces results similar to DV Processor.)

    The PlayMemories file appears to have only one 16-bit audio track. The DV Processor file appears to have two 12-bit audio tracks. Also, (and this may be a red herring) when I play either file in VLC, it reports that the audio is 16-bit.

    So, here are my questions:

    - Is DV Processor correctly capturing the original audio without re-encoding it at a lower bit rate?
    - Does anyone know or can you speculate what PlayMemories is doing with the audio? I suspect it is re-encoding the 12-bit stream as 16-bit for some standardization reason?
    - Why does VLC report 16-bit for both files? Assuming the DV Processor output really contains only the 12-bit tracks, does VLC up-convert?

    I prefer the DV Processor tool over the other tools for several reasons and would prefer to use it, but I am again just trying to ensure I am capturing the original data as faithfully as possible.

    I appreciate any insight or help anyone can offer.
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  2. Member Cornucopia's Avatar
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    12bit streams are what may exist on tapes, but storage of DV data on pc disks usually conforms to the standard practice of keeping everything byte-aligned (8bit, 16bit, 32bit, 64bit, but maybe no 24bit and probably not 12 or 20bit).

    One app may keep as-is, another app may pad the 4 LSBs with 0s. MediaInfo is known to have difficulties in this specific area. Very unlikely, though not impossible, for an app to re-sample and/or corrupt the stream. Esp. since it is usually just a simple incoming sample transfer.

    Scott
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  3. Thank you, Cornucopia. This makes a lot of sense.

    Based on what you said and looking again at the files sizes of the two test cases and their MediaInfo reports, I think the PlayMemories program probably padded the bytes of the audio track and then created a new independent audio track that is not muxed in with the video. I am going to run a couple more tests with recordings from the new camera set to 12-bit and then 16-bit, and I will report back with any revelations.

    Regardless, it seems pretty safe to assume then that the underlying audio in each case is effectively the same digital info.
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    DV audio is either two channels at 16/48 or four channels at 12/32. If you recorded at the lower bitrate, your tape has four audio channels (in two stereo streams) whether you used them or not. They all come over the FireWire connection and you should be seeing them in the DV-AVI file.
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  5. Member Cornucopia's Avatar
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    It often happens (due to the capping app) that 4ch x 12bit x 32khz is capped & stored using only 2 of the 4 channels.
    Note that this is actually usually specific to Type 2 container subformats (of AVI or MOV). Type 1 subformats or raw containerless stream formats assume the data stream is still the original muxed DV data (V + A + A + meta/user). Type 2 keeps the DV stream but relabels it a V only, and "extracts" and copies an audio portion to separate "Audio" track-type streams in the container. It is this extraction which limits the # of channels. And you can no longer access the audio portion embedded within the original DV muxed stream (because it is now only considered "video").

    A good, though time consuming, way around that is to cap twice: once targeting tracks 1 & 2 and once targeting 3 & 4. Then sync, trim & overlay edit.

    Scott
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    AVI Files Containing DV Video and DV Audio Streams (Type-2)

    Interleaved DV data can be split into a video stream and one to four audio streams within an AVI RIFF file. This has the advantage of being backward-compatible with Video for Windows, because it contains a standard video 'vids' stream and at least one standard audio 'auds' stream The primary disadvantage is that this file format requires the audio data to be redundantly stored as audio streams. The "video" stream is actually the native interleaved DV data stream.
    https://msdn.microsoft.com/en-us/library/windows/desktop/dd388641(v=vs.85).aspx
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  7. aBigMeanie aedipuss's Avatar
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    you may have recorded the audio in 12bit 32 khz but the camera was only capable of stereo and didn't use all 4 available channels. that leaves 2 channels unused. set the playback camera to 12 bit 32 khtz before playing the tapes back and use windv in type II to capture. it will capture the stereo 12 bit audio.
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  8. Member Cornucopia's Avatar
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    Originally Posted by JVRaines View Post
    AVI Files Containing DV Video and DV Audio Streams (Type-2)

    Interleaved DV data can be split into a video stream and one to four audio streams within an AVI RIFF file. This has the advantage of being backward-compatible with Video for Windows, because it contains a standard video 'vids' stream and at least one standard audio 'auds' stream The primary disadvantage is that this file format requires the audio data to be redundantly stored as audio streams. The "video" stream is actually the native interleaved DV data stream.
    https://msdn.microsoft.com/en-us/library/windows/desktop/dd388641(v=vs.85).aspx
    Never said the container couldn't hold mutiple DV tracks. I said capturing 2 vs 4 tracks into Type 2 files is highly dependent on the capping app. And most of them do only 2 at a time. I know this having done extensive testing of all the leading capping apps, specifically regarding capabilities and differences between types 1 and 2.
    Look at some of my past posts where I've discussed this...

    Scott
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  9. Thanks all - good info.

    After running a few tests with the new camera and a bit more research of Cornucopia's posts and elsewhere, I believe the following is going on: (This is probably obvious to the old pros here, but I provide it in the event it is useful to someone.)

    - In 12-bit mode, the Sony camera records the stereo audio from the microphones on two of the four 32-kHz audio tracks and leaves the other two tracks blank for future dubbing.
    - For 12-bit source material, when Type 1 is selected, Enosoft DV Processor faithfully captures the stream and creates a Type 1 avi with the 4 tracks muxed into the video. MediaInfo reports it as 12-bit, but maybe it is byte aligned and VLC thinks it's 16-bit?
    - For 12-bit source material. Sony PlayMemories captures the stream, but creates a Type 2 avi with a new 16-bit audio track. I assume the 12-bit data is padded to create the 16-bit audio track. There does not appear to be any setting in the Sony program for Type 1 / Type 2.

    - In 16-bit mode, the Sony camera records the stereo audio from the microphones on the (only) two 48-kHz audio tracks.
    - For 16-bit source material, when Type 1 is selected, Enosoft DV processor captures the stream and creates a Type 1 avi with the audio track muxed into the video.
    - For 16-bit source material, Sony PlayMemories captures the stream, but creates a Type 2 avi with a new 16-bit audio track.

    Interestingly, even though Sony seems to create a Type 2 avi, it won't play in the native Windows 10 Photo app, but the Enosoft Type 1 avi will.

    So given all of the above, I am sticking with Enosoft and disabling the irritating Sony app.
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