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  DVD (-ROM) image access speed question (Message 1 to 7 of 7)  
From: gregjohn
Subject: DVD (-ROM) image access speed question
Date: 8 Jul 2009 07:55:00
Message: <web.4a548845848a538634d207310@news.povray.org>
Hi. I'm working on a project which will involve giving some people a DVD with
files that can be accessed by HTML. I'm presuming they'd have every processor
speed and OS under the sun.  I have a cover page on which I display thumbnails
of twenty different images from various directories across the DVD.
Understandably, it loads a little slowly.

Q: How can I speed this up?  What's the best approach:
i) put all of the images into one directory to reduce DVD access time (tried,
didn't help much)

ii) If I'm going to do < i m g s r c ""  h e i g h t = X,  then I should just
save a new, resized copy of the image with  that height instead of asking HTML
to resize images which are 5X that size.

iii) Make one composite image and then use that click-on-a-bitmap- thing in
HTML.


Q: Can anyone point me to an online tutorial, or better yet, to the exhaustively
correct terminology so that I may google it, of how to create autorun files?

thanks.


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From: Invisible
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 08:19:36
Message: <4a548ed8$1@news.povray.org>
gregjohn wrote:
> I'm presuming they'd have every processor
> speed and OS under the sun.  I have a cover page on which I display thumbnails
> of twenty different images from various directories across the DVD.
> Understandably, it loads a little slowly.

All optical disk formats that I'm aware of have very long seek times. 
Reading lots of small files is very slow with such disks.

I'm no expert in this field, but I don't think any of them have a very 
high maximum transfer rate either. For example, a 1x CD-ROM drive 
transfers 10MB of data *per minute*. That's 1MB every 6 seconds. Of 
course, newer CD-ROM drives are usually 48x or something, which takes 
you closer to 10MB per second. And DVD is faster still. (But I don't 
know exactly how fast off-hand.)

[Wolfram Alpha claims a DVD transfers 5 megabits per second, which would 
be about 0.6 MB/second.]

> Q: How can I speed this up?  What's the best approach:
> i) put all of the images into one directory to reduce DVD access time (tried,
> didn't help much)

This is unlikely to help at all. It might minutely reduce the amount of 
seeking required to read the directory tree, but it won't help read the 
files any faster or seek to them any quicker.

> ii) If I'm going to do < i m g s r c ""  h e i g h t = X,  then I should just
> save a new, resized copy of the image with  that height instead of asking HTML
> to resize images which are 5X that size.

This may well help, since you have less data to transfer. (You still 
have the seek times, however.)

> iii) Make one composite image and then use that click-on-a-bitmap- thing in
> HTML.

This should also help, by putting all the image data into a single 
contiguous block, thus eliminating seek time penalties.

> Q: Can anyone point me to an online tutorial, or better yet, to the exhaustively
> correct terminology so that I may google it, of how to create autorun files?

http://en.wikipedia.org/wiki/AutoRun

You need to add a file named Autorun.inf to the root directory on the 
DVD, containing something like

   [autorun]
   open=root.html
   icon=icon.ico

This works ONLY for Microsoft Windows; I'm not sure if any similar 
functionality exists for other operating systems...


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From: scott
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 09:18:19
Message: <4a549c9b@news.povray.org>
> ii) If I'm going to do < i m g s r c ""  h e i g h t = X,  then I should 
> just
> save a new, resized copy of the image with  that height instead of asking 
> HTML
> to resize images which are 5X that size.

Yes, do this.


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From: Darren New
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 12:28:22
Message: <4a54c926$1@news.povray.org>
gregjohn wrote:
> ii) If I'm going to do < i m g s r c ""  h e i g h t = X,  then I should just
> save a new, resized copy of the image with  that height instead of asking HTML
> to resize images which are 5X that size.

If the problem is seek time, this won't help as much as you think it might. 
Try it and see.

> iii) Make one composite image and then use that click-on-a-bitmap- thing in
> HTML.

This is what I'm guessing will give you the best shot.


> Q: Can anyone point me to an online tutorial, or better yet, to the exhaustively
> correct terminology so that I may google it, of how to create autorun files?

I don't know about that, but I created an autorun file for my vacation 
photos on one DVD. Here's what I had to do:

AUTORUN.INF holds
[autorun]
open=showme.bat
icon=italy.bmp

italy.bmp is a 64x60 BMP image. I'm pretty sure white is transparent, but 
play around with it.

showme.bat holds one line reading
start index.html

index.html is the top of the image tree.

Apparently, it needs to be ASCII and not UTF.
http://social.msdn.microsoft.com/Search/en-US/?query=autorun.inf%20format&ac=8
HTH!  It'll at least get you started. :-)

-- 
   Darren New, San Diego CA, USA (PST)
   Insanity is a small city on the western
   border of the State of Mind.


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From: somebody
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 12:56:18
Message: <4a54cfb2$1@news.povray.org>
"gregjohn" <pte### [at] yahoocom> wrote in message
news:web.4a548845848a538634d207310@news.povray.org...

> ii) If I'm going to do < i m g s r c ""  h e i g h t = X,  then I should
just
> save a new, resized copy of the image with  that height instead of asking
HTML
> to resize images which are 5X that size.

Why would you NOT do that anyway, be it DVD or www?


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From: Darren New
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 13:03:47
Message: <4a54d173$1@news.povray.org>
somebody wrote:
> Why would you NOT do that anyway, be it DVD or www?

It's extra coding and it takes more space on the disk. :-)

-- 
   Darren New, San Diego CA, USA (PST)
   Insanity is a small city on the western
   border of the State of Mind.


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From: Jim Henderson
Subject: Re: DVD (-ROM) image access speed question
Date: 8 Jul 2009 13:42:10
Message: <4a54da72$1@news.povray.org>
On Wed, 08 Jul 2009 07:51:33 -0400, gregjohn wrote:

>   I have a cover page on which I
> display thumbnails of twenty different images from various directories
> across the DVD. Understandably, it loads a little slowly.

Quicker would be to generate the thumbnails and join them into a single 
image and use an image map - then it's loading one image instead of a 
bunch of small images.

Jim


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