DVD authoring and AC-3 ??

[davefred99]

I have been using BTV-3 for a couple of months now and have pretty much sorted out all the little bugs that have popped u from time to time. I have build up a fair sized library of movies and shows on my hard drive. I now am starting to archive a lot or the movies by burning DVD's. The process has been fairly painless do to the many posts and guides on the subject.
I am mostly using Ulead MovieFactory to Author and add chapters to my DVD's. I generaly have Ulead creat a DVD folder and then run the finished movie files thru DVD Shrink to make them fit on one DVD and burn with the Nero burn engine.
One thing that I figured out real quick is that I needed to manualy tell Ulead Movie Factory to save tha audio in Mpeg-1 layer-2 (Mp2) audio. By default Ulead wants to convert the audio to a much larger wave file format which waistes a lot of valuable disk space.
My question is would I gain anything by by converting the audio from Mp2 to Ac-3 or is that a waist of time. I ask this because sometimes my Sony Dvd Player doesnt want to recognize my home made Dvd's with Mp2 audio. I Know that The standard Ntsc audio formats for DVD's are Ac-3 or Pcm (wave). I noticed that Tpgenc. offers an AC-3 plugin that can convert these mp2 files to AC-3. What happens to the standard Dolby prologic info when converting to AC-3 format. Anyone have any first hand experiences with this.
Thanks, Dave

[_Shorty]

there's not much point going from one lossy format to another except in this case, you just compound losses/artifacts/etc. If you had access to the original uncompressed data then choosing one over the other might be wise. But converting from one to the other, especially when your player will play either one, doesn't make any sense.

edit - whoops, would make more sense if I actually typed out the word 'except' there, heh. changes the meaning entirely when you only think about typing it, haha.

edit - oh, and dolby pro logic *is* just 2 channel stereo to begin with anyways, so it should be fine, just the same as the mpeg layer 2 is just stereo.

[davefred99]

Originally posted by _Shorty
there's not much point going from one lossy format to another except in this case, you just compound losses/artifacts/etc. If you had access to the original uncompressed data then choosing one over the other might be wise. But converting from one to the other, especially when your player will play either one, doesn't make any sense.

edit - whoops, would make more sense if I actually typed out the word 'except' there, heh. changes the meaning entirely when you only think about typing it, haha.

edit - oh, and dolby pro logic *is* just 2 channel stereo to begin with anyways, so it should be fine, just the same as the mpeg layer 2 is just stereo.

I was was thinking that there probably was nothing to be gained except that maybe a little better playback compatability on some players that dont want to recognize the mp2 audio tracks. I actualy find the mp2 audio to be very good and it does support the dolby proligic sound. At least I hear sound from all my speakers during action scenes.

How would one go about capturing the true dolby digital (ac-3) off of a digital source like direct Tv. I know the information is there and some receivers have digital or spdif outputs. I have heard that the Pvr-250 cards have some AC-3 capabilities built into them but not implemented do to licensing restrictions. Surely as we progress into HD tv it will be a must have option.

[_Shorty]

yeah, that's what I was trying to say, that if your player doesn't seem to get along with the layer 2 audio then in that case it would make sense to transcode it to ac3 just to avoid the headaches. But if your player doesn't have any problems with it, then you are better off leaving it as-is since layer 2 audio is actually pretty good. It would be nice if BTV would give you the option of using bitrates higher than 224kbps though. I believe someone mentioned that the pvr-250 can do 384kbps audio, but the option just isn't present in btv itself, so hopefully they'll remedy that. Probably wouldn't hurt to send an email requesting just that, to the support email address. Perhaps I'll do that, actually. A few similar requests probably wouldn't hurt either ;) I wonder if it'll accept the bitrate if you manually edit the xml file containing the 'recording quality' settings...

edit - oh...I don't think there is any way to snag the ac3 data straight off the receiver right now, would definitely be nice.

[jsutton2871]

dave,
you asy u use dvd shrink is that part of uleads package? i use ulead movie factory but dont find shrink as part of the package?
thanks

[guantamanera]

I don't know why you guys have problems with the layer II audio.
That is suppost to be more compatible than the AC-3. Layer II is part of the mpeg2 standard. Any ways here is how I get AC-3 audio from the satellite.
Buy yourself a DVB card.
Get a dvb program like http://www.progdvb.com Progdvb or http://www.dvbcore.com Mytheater
Read alot in how to get them working and you'll get AC-3 and very good MPEG2.

It works for does not work with DirectTV, but works for DIshnet and EXpressVU.

The signal in the satellite is already MPEG-2 so there is no encoding needed. I'll be just like copy and paste. You get there Original MPEG the satellite send since you did not do a convertion from digital then to analog and back to digital. I'll be a professional encoded MPEG. But the video size is not up to standard. The video is 544X480, But my dvd player does not care about the file and still plays. My xbox dvd player also plays it with no problem or if you want to make it standard you can resize the image.
In the website http://www.doom9.org Doom9 they have good tutorials in how to convert the signals into DVDs.

[guantamanera]

Muhahaha go here (http://forums.dvbnetwork.com) and see what those dvb cards can do. They can even get HDTV. And record it too, but you need a beefy computer.