Posted by TheFlaggman on 11/27/07 23:37

On Nov 25, 1:17 am, "jazu" <nofreakings...@nospam.com> wrote:
> Hi
> I have Sony DCR-HC28.
> When I capture footage to computer I have sometimes bad audio quality.
> When I play tape on camcorder looks like audio is OK.
> Somewhere in capturing process I got randomly bad shaky audio.
> Anyone would know more about the problem. Why it happens and how to fix it?
> thanks

If you use windows OS and have networking and anti-virus or anti spam
software running as well as any servers like ftp or www ( IIS, PWS,
Apache etc.) they all use a lot of resources and time slice processor
time. If memory and processor are being taken away so that virtual
paging is used disk accesses also can be a problem.

Whenever I capture, edit, or render videos to final file outputs or
DVD's I make it a practise of turning OFF all network connections 1st
(especially if you are on a company network that runs invisible
software inventory and snooping diagnostics). Then go into the task
manager and make sure all the applications and processes running are
ONLY the ones you really need for a stable OS operation with you video
editor running. This will free up memory, reduce the need for disk
accesses in the middle of audio and/or video rendering or processing.
As you might expect, any interruption of the CPU in the middle of
processing audio and video will result in sort of glitch if you are
lucky, and a total freeze-up if you are not ! Make sure connectors
you use are clean and fit securely as a loose one that looks OK on the
surface can have an oxidized coating and give you static noise in
either or both audio and video.

Make sure the lines between the camera and the capture card are direct
and only as long as needed, and be sure they don't hang or drape
across things like UPS's , power supplies, monitors or even ordinary
AC power cables as all these items radiate interference and or
magnetic fields that can introduce unwanted noise or hum into your
feed to the PC. Where USB is concerned if it is the USB 1 some
devices have a memory resident software running that cycles like a
diagnostic and might cause breaking up in either audio or video.

Also all the old analog audio levels are set to work at a level of 0VU
(+4 dbm) which is way too high for digital. Any slight peak of audio
above the maximum allowable for digital which is usually in the range
-12 up to -4 MAX will cause irrepairable damage to the audio, like
popping and scratching. In this case set all level controls in the
"recording" and "playback" properties to the half way point and NOT
full up to max, then record the project. If during your final editing
stage you find it to be a little low, then increase it using the
editor. Be careful using that automatic "normalizer" as well as it
will jack levels up out of site as well and cause all kinds of
distortion and static problems. Kind of a rule of thumb that I found
works well is " You can always turn up something that is a little low;
but turning down digital distortion is still going to give you digital
distortion only at a lower level. Once distortion is in the digital
world it is there for keeps, and unlike the old analog mixers etc,
there aren't any cheats or effects that can be applied to get digital
distortion out. Digital is nice looking, convenient, but darned
unforgiving when you don't stick to it's rules. It kind of reminds me
of the business - consumer relationship you will play ball businesses
way or will receive a deposit of the bat in an area of your body you
aren't wanting it ....hehe

In the past, analog era no pro broadcaster would accept anything like
what is now a fact of life in this new and better digital age. Watch
your local news clips etc and see how many burps, digital dropouts
frozen audio and pixelated screens they say "cope and get over it ; it
is a fact of life with this new and 'improved digital age'.

If you are using LINUX, then you might have to create an init run
level tailored only to run the daemons and software packages you need
for the editing task specifically, and keep all other things like
servers and networks turned off. When done then just reboot the run
level to a normal one not used for editing.
( eg. init 0 usually is power off and shutdown; init 3 single user
command line mode; init 6 id reboot to default mode and init 5 is
usually start with a graphical user interface screen; so you might
want to create a corresponding customized init 4 package to do
critical editing and rendering.).

Good Luck with it.

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