Re: [MLUG] video compression

["Mark Rages" <EMAIL:PROTECTED>]

On Jan 7, 2008 2:37 AM, Mike Miller <EMAIL:PROTECTED> wrote:
> My digital video camera stores raw video on tapes that I transfer to my
> hard drive where they consume about 13 GB/hr .avi files.  I would like to
> retain all the information in the original files somehow and be able to
> reuse the digital tapes, but the files are too big to fit on a DVD.  I
> compressed a 677 MB avi file using gzip, but the resulting .avi.gz file
> was still 599 MB, and it took a long time to compress.
>
> Maybe I can just process the .avi files in the usual way to make video
> DVDs without experiencing a noticeable loss of video or audio quality.
> Do any of you have experience with this?
>
> Mike

I have loads of experience with digital video.

Standard definition digital video is stored as "DV" data. Both
"miniDV" and "digital8", as well as professional formats use this
compression system: http://en.wikipedia.org/wiki/Dv

DV is great for editing because each frame stands alone.  In contrast,
MPEG achieves compression by referring to frames previous and
subsequent in the stream.  DV is "light" compression, and still looks
good after a few generations of compression and decompression.

The best way to archive the tapes is with external hard drive
enclosures.  (or LTO backup tapes, if you've got lots of data).  A 1TB
USB drive is less than $250.  You should store at least two copies,
using disks of different manufacturers, in two physical locations.
Every five years, copy the data to new disks.  The data will be lost
when you stop doing this.

DV-wrapped-in-avi is not my favorite format because it stores many
pieces of information in two layers in the stream.  But it's probably
not worth demuxing out the original DV data, it's just some Microsoft
brain-damage to deal with.

The most common workflow is probably like this:
record DV in camera --> capture DV to computer --> edit on computer
--> export edited data as an MPEG-2 DVD-Video.

although youtube is becoming more popular as an output format.

Regards,
Mark
EMAIL:PROTECTED
-- 
Mark Rages, Engineer
Midwest Telecine LLC
EMAIL:PROTECTED

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