Thread: [linux-1394-devel] DV Backup?
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From: Olivier L. <la...@cy...> - 2000-05-31 05:42:52
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Hello, Would it be possible to use a camcorder (that has dv-in) as a backup = device by encapsulating backup datas in the video sequences in a faked DV = format? If I understand well the camcorder behaviour, in dv-in mode, it only = store the DV datas on the tape. right? That would be cool to do: tar cvf /dev/1394tape / 2Go in less than 10minurtes :-) |
From: Andreas B. <and...@mu...> - 2000-05-31 22:19:37
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On Wed, May 31, 2000 at 07:40:20AM +0200, Olivier LAHAYE wrote: > Hello, > > Would it be possible to use a camcorder (that has dv-in) as a backup device > by encapsulating backup datas in the video sequences in a faked DV format? > > If I understand well the camcorder behaviour, in dv-in mode, it only > store the DV datas on the tape. right? From what I know, the DV data is always sent over isochronous streams, which might lose data since they are broadcast and there is no acknowledge from the receiving end. Acceptable for video data, but certainly not for your backups. -- Andreas E. Bombe <and...@mu...> DSA key 0x04880A44 http://home.pages.de/~andreas.bombe/ http://linux1394.sourceforge.net/ |
From: Stephane G. <Ste...@li...> - 2000-06-15 19:40:48
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On Wed, 31 May 2000, Olivier LAHAYE wrote: > Hello, > > Would it be possible to use a camcorder (that has dv-in) as a backup device > by encapsulating backup datas in the video sequences in a faked DV format? > > If I understand well the camcorder behaviour, in dv-in mode, it only store the DV datas on the tape. right? > > > That would be cool to do: > > tar cvf /dev/1394tape / > > 2Go in less than 10minurtes :-) As someone pointed out, the DV format is thrown through the interface as isochronous data, which means that bandwidth is guaranteed but not integrity of data (hem). Moreover, the Hi8 tape are not "data quality" but, unles advertised, only "good enough for consumer video". There are, though, some means of introducing redundancy in the signal (like on CD audio and CD Rom) to enable perfect data recovery under not-too-important medium failures. It might be done if people investigate this way, but it might be simpler, cheaper than a DC camcorder, and more reliable, to wait for a ieee1394-based tape steamer device, or a plain SCSI-based one as they are sold for now... -- Stéphane Gourichon - Laboratoire d'Informatique de Paris 6 - Équipe AnimatLab |