The "DV" in miniDV = Digital Video. Zeroes and ones like flash memory, hard disc drive and DVD storage, just in a different format ("DV" on tape).
VHS and VHS-c are analog video.
The information stored on the tapes VERY different and there is no "cross-compatibility". Like digital TV vs analog TV...
I will hazard the tape you were sent was recorded in LP mode (longer tape record time). You can try setting the JVC to LP mode, but this generally does not work too well. The only resolution I have seen consistently work in the past generally involves using the same model camcorder in LP mode. Many times a similar model from the same manufacturer can do the deed, too.
The SP recording tape speed should always be used... I have not seen compatibility issues, unless one of the camcorder's tape heads are not properly aligned.
I have a 2004 JVC video camera, model #GR-D30U that records and plays back my Sony Mini DV video cassettes. My kids sent me a Panasonic Mini DV cassette that they had taken of my granddaughter's graduation in their camera and it fits into my camera properly but will not allow me to view it on my camera screen. I know of no available adapters that are available that allow Mini DV cassettes to be played on a vcr player other than the vhs-c adapters which of course are not compatible with Mini DV cassettes.
Anyone have any ideas how I can get this cassette to play on my JVC camera? Thanks!
Scotty

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