Any mathematical equation or program to determine just fit

[solidsnake]

Since my recorder doesnt have "just fit" and I assume alot of other recorders dont have it, does anyone know a way to determine how much a disc can record in a good quality mode, then use the minimal amount of time to record the rest of the recording in a lower quality mode when recording a movie that runs, lets say.....2hr, 20min.
Do you think this can be solved by using a mathematical equation you could figure out yourselves, if so does anyone think they can come up with one? Or is there a freeware program that can automatically do it for you? I'd like to use up most of the disc with the best quality, then if I know its going to go over the time limit, how long into the recording should I switch to a lower quality and still be sure I wont run out of space, but still use the whole disc to its fullest. And lets assume that
HQ=1hr
SP=2hr
LP=3hr
EP=4hr
SLP=6hr

[jimmalenko]

You should be able to get the specs (in particular, bitrates used) for each recording mode from your DVD Recorder manufacturer's website for the different modes. From there you could just use a bitrate calculator to work everything out manually, or you could do some tinkering with a spreadsheet and allow it to calculate whatever you want given a couple of variables such as time already on the disc, and time left to go.

[midnightsun]

Here you go:

H:M is the length of the material you want to record, where H is hours and M is minutes.

X is the length (in minutes) you can record using the better of the two recording modes neighboring the running time at hand (example: if you want to record stuff that is 2:10 long, the two recording modes involved would be the 2-hour and 3-hour modes).

Equation:

[X/(H*60)]+[[(H*60)+M-X]/[60*(H+1)]]=1

You're filling up the disc ths way.

Solving for X:

X=H*(60-M)


Example: you want to record 2:20, so H=2, M=20 =>

X=2*(60-20)=80

So you can record 80 minutes in 2-hour mode and what's left (140-80=60) in 3-hour mode

Note: this equation works ONLY with 1-hour intervals between each recording mode (because the second denominator is set as 60*(H+1)).

With 4 and 6-hour modes the equation to be used is:

[X/(4*60)]+[[(H*60)+M-X]/[60*6]]=1

Solution:

X=2*[360-(H*60)-M]

Enjoy

[lordsmurf]

Two trains leave the station at exactly the same time. Train A is going 92mph, while train B is going 73mph. Train A......... zzzzzzzzzzzzzzzzzzzzzzzzzzzzz

[midnightsun]

well I just answered somebody's question. What's the problem?

[lordsmurf]

Nothing.

I just wonder what's wrong with just hitting "3-hour", recording, and when done, then changing to another mode and simply looking at the on-screen display for info on remaining time. All recorders can do this, at least ones I've seen (which is most recorders).

A lot easier than the other method.
Seriously, I lost you right after you said "Here you go".
I was gone.

[midnightsun]

yeah the answer was pretty much straighforward, but I figured that if he asked he might be glad to get an answer.

At the end of the day, I just answered for the fun of it.

[edsmith77]

And to carry this to another illogical end. The equations do work and as advertised by the author. However, they do not include any optimization, which, IMHO, the original question was asking.
And YES, this is beyond my mathematical capabilities (I think).
My point is that the exercise was to put the most of the HQ recording on the disk and then fill in the rest will a lower quality recording. Here bit rate is the driver for quality.
From the example, if possible why not go for 2Hr 05 min of HQ and then go for 5min of very low quality? Or should I go for 2Hr of HQ then 10 min of not so very low quality or mayber there is a different set up. This just seems to me to beg of optimization or in math terms multivarate calculus. UGH>>>>> If I recall sometime / some place in my past, I recall doing that sort of thing (in school). Never did see much real point in that until now. Sure wish I had not fallen asleep.

Ed

[Harpmaker]

solidsnake,

If I understand your question you want to record at a high bitrate, and then if you see the whole recording won't fit on one disc, to stop recording, change to a lower bitrate setting, and then continue recording the program until the disc is full. All on the same program or movie. Many VCR's will do this automatically, but no DVD recorders will, that I know of. It would be a cool feature, but with DVD's I don't even know if it's possible, I suspect it would cause playback problems.

To do this manually would be impractical as you would lose a lot of the movie by having to stop the recording, change bitrate, and begin recording again. On all the DVD recorders I know of you would also have two separate recordings on the disc.

I've seen bulk DVD's selling for less than 20 cents each. Don't worry about "losing" 10 or 20 minutes at the end of a disc. Something else to keep in mind is that the closer to the outside of a disc you record, the more likely you are to get errors in the recording because of disc physics. CD's and DVD's record from the inside (hub) out.