Newbie Question: DVD Capacities

I know this is a basic newbie DVD-writing question, but I have it:

I've begun playing around with burning my own DVDs using the video that
I pull off my ReplayTV unit, and I'm very confused about the capacity of
the DVD+R's and DVD-R's that I write. In a nutshell, using best quality
video, I can get about an hour worth of video on a DVD+-R disc -
however, I know that on a movie DVD that I buy, the movies on those
discs are 2-3 hours in length, in full quality. So what is the basic
differences in the DVD's? Are there simply different types of DVD media
beyond the DVD+-R's that I use for self-authoring? What is the capacity
of the DVD's I buy and what type of media are they compared to what I'm
trying to burn?

Chris Kotchey

"Chris Kotchey" <> wrote in message
news:kOe6d.24631$...
> I know this is a basic newbie DVD-writing question, but I have it:
>
> I've begun playing around with burning my own DVDs using the video that
> I pull off my ReplayTV unit, and I'm very confused about the capacity of
> the DVD+R's and DVD-R's that I write. In a nutshell, using best quality
> video, I can get about an hour worth of video on a DVD+-R disc -
> however, I know that on a movie DVD that I buy, the movies on those
> discs are 2-3 hours in length, in full quality. So what is the basic
> differences in the DVD's? Are there simply different types of DVD media
> beyond the DVD+-R's that I use for self-authoring? What is the capacity
> of the DVD's I buy and what type of media are they compared to what I'm
> trying to burn?

On burnable media you use at home, you have up to 4.7Gb of space for
single-layer media, or aprox. 8.5Gb on the new super-expensive
dual-layer(DL) media. What you do with the space is your business.
Commerical disks are pressed not burned, and come in sizes from 4.7, up to
aprox 18Gb.

Biz

Chris Kotchey <> wrote in message news:<kOe6d.24631$>.. .
> I know this is a basic newbie DVD-writing question, but I have it:
>
> I've begun playing around with burning my own DVDs using the video that
> I pull off my ReplayTV unit, and I'm very confused about the capacity of
> the DVD+R's and DVD-R's that I write. In a nutshell, using best quality
> video, I can get about an hour worth of video on a DVD+-R disc -
> however, I know that on a movie DVD that I buy, the movies on those
> discs are 2-3 hours in length, in full quality. So what is the basic
> differences in the DVD's? Are there simply different types of DVD media
> beyond the DVD+-R's that I use for self-authoring? What is the capacity
> of the DVD's I buy and what type of media are they compared to what I'm
> trying to burn?

The studios are using dual-layer discs which double the storage capacity.

Check out some info here:

http://www.dvddemystified.com/dvdfaq.html#3.3

Smaug69

Smaug69

"Chris Kotchey" <> wrote in message
news:kOe6d.24631$...
> I know this is a basic newbie DVD-writing question, but I have it:
>
> I've begun playing around with burning my own DVDs using the video that
> I pull off my ReplayTV unit, and I'm very confused about the capacity of
> the DVD+R's and DVD-R's that I write. In a nutshell, using best quality
> video, I can get about an hour worth of video on a DVD+-R disc -
> however, I know that on a movie DVD that I buy, the movies on those
> discs are 2-3 hours in length, in full quality. So what is the basic
> differences in the DVD's? Are there simply different types of DVD media
> beyond the DVD+-R's that I use for self-authoring? What is the capacity
> of the DVD's I buy and what type of media are they compared to what I'm
> trying to burn?

As you observe, you get 59 minutes of video using PCM sound on a 4.7 Gb
blank disk using the (normal) maximum data rate. Commercially mastered
movies use a variable compression technique not available to us mere
amateurs, whereby the data rate is high when the image is rapidly changing
and at a much lower rate for images where not a lot is happening. This
gives a vastly extended playing time, and once you go to double layer disks,
several hours become possible.

For home produced stuff from a decent DV camcorder, it should be possible to
lower the data rate to provide 1hr 58 mins of recording, but the results
depend very much on how good the MPEG compression software that you use is.
Generally the amateur (i.e. cheap) ones seem to vary somewhere between awful
and mediocre at these low rates, but the real time compressors in video DVD
recorders are surprisingly good. You need to go to the very expensive
professional software systems to get decent results.

It should be noted that if you use MPEG audio instead of PCM, the recording
time of 59 minutes extends to 1hr 15mins. However there are issues with
MPEG sound. It isn't quite as good for a start, but more so, many DVD
players have been found that momentarily freeze at chapter or title points.
The reason for this is not clear. None of the PC DVD playing software does
it to my knowledge.

Until dual layer authoring systems become available, you are probably stuck
with 59 minutes, but if you are producing holiday videos, you audiences may
be grateful. Note that you cannot just produce a large production and then
just burn it onto daul layer. It has to be correctly authored to overcome a
technical limitation of dual layer reproduction.

Ian.

Electric Fan Club