Why do 3 hour movies not fit on a dvd?????

[eggedd2k]

this ones been baffling me all day.

i've got an avi file i want to convert to dvd (well m2v + wav) in tmpgenc plus.

it's just under 3 hours long. when i use the wizard to set everything up it gives me an average bitrate of 3000 which according to the program will give me a file size of 5.4 gig - too big for a dvd.

if i lower the bitrate - 2000 is the closest i can get to fitting on a dvd the resulting mpeg is dead grainy.

how do other folks manage to convert a 3 hour movie to mpg whilst maintaining quality/a decent bitrate? is there some other software i should be using?

thanks in advance!

[FulciLives]

Use MP2 or AC3 audio.

If you want to use the calculator buiit-in with TMPGEnc Plus then use MP2 but in the end (after conversion) go back to the original WAV file and convert it to AC-3 using something like ffmpeggui as AC-3 is better than MP2. Just make sure you use the same bitrate in TMPGEnc Plus for the MP2 as you will for the AC-3 ... the file size will be the same that way.

You must be using the LPCM audio option in TMPGEnc Plus hence the ultra low bitrate for the video as LPCM is like 1536kbps vs 192kbps to 256kbps for AC-3

- John "FulciLives" Coleman

[eggedd2k]

i dont really want to use AC3 coz it always turns out really quiet.

[FulciLives]

i dont really want to use AC3 coz it always turns out really quiet.

Then you aren't doing it right although truth be told you do need a good AC-3 encoder with proper settings.

- John "FulciLives" Coleman

[eggedd2k]

ah i've just spotted the mp2 option in tmpgenc. filesize is spot on now.

thanks for your help m8

[greymalkin]

If you're interested in how other folks get 3hours on a dvd there are a few answers:

1) sometimes they reduce the resolution to half D1 and then use the lower bitrate. It allows you to use a lower bitrate without artifacts but the tradeoff is that it softens the image.

2) If you want to keep a higher bitrate then you need a dual layer dvd. Now you can put about 8gb on a dvd.

3) Another way to get your video smaller is by using a variable bitrate instead of a constant. Mpeg works by tracking changes between frames. When there is very little movement in a sequence of frames, very little bitrate is needed. On the other hand, if you have fast moving action scenes or scenes where a lot is going on the screen then much bitrate is needed.

4) If you are asking how the hollywood movies cram so much on dvd's..well that's some crazy voodoo magic that you don't have the money or time for .

[edDV]

i dont really want to use AC3 coz it always turns out really quiet.

Just like HDTV AC3, it is quiet because it has greater S/N ratio. Noise works from saturation down. The better your headroom, the higher the volume control is set for normal audio.

A good receiver will scale the volume % to the source but most don't.

At one extreme you have compressed AM radio. The volume seldom changes.

At the other extreme you have AC-3 or DTS from DVD or ATSC. You crank the volume up to hear the soft passages then when the explosions hit you,

1. Have a blown amp.
2. Hear a very loud explosion.
3. Have police respond to neighbors complaint.

[lacywest]

Well if I was doing this project ... I perhaps would make the 3 hour movie Tmpgenc Plus [and not let the bitrate or the size be a factor] and then use DVD-RB to squish it down.

On my computer[s] I have DVD-RB set for 7 pass with the CCE 2.50 encoder takes around 300 minutes. But a 3 Hour movie will take a little longer.

I processed a XXX movie that is 3 hours long ... I wasn't sure how well the quality would be ... but watching it on my 51" Sony HD TV ... hmmm not bad.

And yes ... yes ... I use to use 9 Pass and quite a few people commented that it is a waste of time using 9 Pass .... 4 to 5 passes is recommended. So I compromised and set it to 7 Pass. I do my processing on my wife's computer ... same system as the one in my profile ... while I'm at work or when I'm sleeping.