DVDshrink audio question.

[Beautiful Alone]

what are these AC3 6-ch english and AC3 2ch english etc..? so the 2ch is for normal tv's with 2 speakers and the 6ch is for 6 speaker or 5, 3, etc?

[twinches]

Yes the 2ch is for playback for normal tv's for stereo sound. The AC6ch is for 5.1 home theater systems where you would have a left and right speaker, center speaker, a left and right rear speakers and a sub woofer. However I have found that you just always pick the AC6ch track that it will also play on normal stereo setups too. So in other words, don't worry about having the AC2ch track and just alwasy copy the AC6ch track as it will play back fine on any TV with any number of speakers.

[Beautiful Alone]

sometimes i have to uncheck the AC3 6ch because i can't compress up a level with shrink. Image is the no.1 priority.

[Gazorgan]

I jsut keep the 5.1 channel since I won't ever use the 2 channel track. Most players will downconvert the 5.1 to the 2 channel output on the back (in Dolby Digital Surround usually). Then if you have digital/optical out you can get teh 5.1 with a compatibly reciever.

I dropped $69.95 on a 100 watt 5.1 reciever with speakers. It's very nice in the bedrooms, more than enough power. Has digital inpoout and autoselects between analog 2 channel and 5.1 digital as needed.

[wulf109]

If image quality is the priority then never choose the 6 channel stream. A 6 channel stream will be 400MB's and 2 channel stream will be 180MB's. That puts another 220Mb's into the video stream by selecting only the 2 channel stream. This is for a typical 2 hour movie. A DTS stream could be 800MB's.

[ddlooping]

Hi all.

If I was you I'd be very careful about not selecting the AC3 6ch stream, as it often the only stream containing the movie soundtrack.
The AC3 2ch is (are) usually a commentary of some sort.

So I'd suggest you check first in your software player (or on the original DVD box).

[Thunder In Paradise]

Beautiful, are you crazy or something? Dropping out the 5.1 Surround track because you want to keep the video quality? Listen for a moment. I've done quite a few longer movies (i.e. in excess of 2 1/2 hours or more, requiring atleast 25-40% compression), while keeping the 5.1 track, with no picture quality loss at all. Movies like The Abyss SE, Braveheart, and Scarface. If your using DVD Shrink, just use the Deep Analysis, that's what it's there for. Some others have noted that when using higher compression settings, some artifacting and whatnot appears, but only on like 50" plasma displays. So if your like the rest of us, (smaller TV's, gotta love the 27" stereo Phillips!), most of the time, you can't notice any quality loss anyways, if there is any.

[adam]

Quality is relative. Many people like myself notice quality loss with even minimal compression in DVD Shrink and even on very small televisions. Quality-wise, transcoding just isn't a very efficient method of downsizing a DVD. Trust me, whether you can see any difference or not, your backups are not as high quality as the originals. I personally don't think dropping the 5.1 track is worth the added video quality, but I most certainly agree that it would improve the quality some.

The 2 channel main audio track is there for only one reason, so that people with Dolby Surround only decoders will still get 4.0 surround.

If you have a 5.1 reciever, a prologic reciever, or no reciever at all, then all you need is the 5.1 track. Its still a good idea to keep the 5.1 track even if your receiver doesn't support it because chances are you will get a capable receiver some time in the future.

[Beautiful Alone]

I always compress my DVD's in re-author mode, sometimes the video is only 3.5 gig with no compression at all in re-author mode, then in full disk DVD mode the main movie is 5 gig with no compression and i don't think that's including the extras.

[Beautiful Alone]

nt

[jimmalenko]

I find it hard to believe that people can claim they "notice even the smallest quality loss" on normal tvs. My opinion: You must have good eyes, superhuman, even.

I hear and read that screens over 1 metre and projection setups magnify the quality defects somewhat but can we honestly say that our backups are not DVD quality by eye ?

If you can I believe you are doing it wrong.

[Thunder In Paradise]

I mean, the only time that I can really "notice" that the movie has some compression artifacts (like if there's something in the foreground, if you look at the background, it looks like it's moving all staccato-ish, not smooth), are movies approaching or going past like 45% or more. Movies that have unnessecarily (spelling I know, it's late) high bitrates, when they shouldn't. (Is there really any difference on a normal TV between 6MB a sec, and 7MB a sec?)

[mats.hogberg]

@Gazorgan:

I dropped $69.95 on a 100 watt 5.1 reciever with speakers.

I'm looking for a similar low end 5.1 decoder/amp/speaker kit - Was that a "special-price-for-you-super-sale" offer, or is it a kit one might find if one kept looking? If so, any pointers on what to look for?

/Mats

[adam]

(Is there really any difference on a normal TV between 6MB a sec, and 7MB a sec?)

Commercial DVDs rarely ever get that high. The typical DVD has an average bitrate between 4 and 5 mbits. If you compress this down to a DVD5 you often get bitrates around 3 to 3.5mbits. Yes, I can see a difference when I use a transcoder, no I can't see a difference if I re-encode it.

Sure some DVDs can be compressed to a DVD5 with minimal compression, or some movies may be very short and have exceedingly high bitrates to begin with. Obviously I am not talking about these DVDs. I am talking about the typical DVD, which yes will lose quality if transcoded.

Don't forget that not everyone is willing to throw out the extras or all the audio tracks just to keep the main movie at a perfectly comfortable bitrate. Many people, like myself, prefer to keep everything within reason and re-encode it so as to get a copy which is both complete and of high quality.

I honestly don't see how you can do something wrong with a transcoder. There are apparantly just some of us who are not happy with what others consider good enough.

You don't need superhuman eyes to see the difference between a transcoder and an encoder at even moderate compression. Due to the way transcoders work they create very distinct artifacts. Maybe some people just don't know what to look for, but once you see it, it is very distracting.

[garryheather]

Don't forget the 2 channel track could also be an alternatiive soundtrack like a director's commentary - personally I like to keep some of those if I can. It isn't always just a "downmix" of the surround programme.

[glenrey]

Who watches there backup movies just to spot any quality loss?
I watch my movies for entertainment purposses only.

[adam]

But if there are noticable artifacts in the backup then its obviously not as enjoyable to watch, right? I don't look for artifacts, I just see them, which is why I like to ensure that there aren't any in my backups.

Its extremely closed-minded to assume that just because you don't see problems in your backups that they therefore don't exist, and that anyone who does see them must be overly scrutinizing. There is a whole world of people out there who have given transcoders a fair try but still find them lacking for most backup purposes. I use transcoders for certain purposes and I find them very convenient. But when I start to see quality loss, and I know I can avoid it using another method, then I go that route instead.

Honestly, it does not take me anymore work to do a re-encode then a transcode. Either way it involves about 5 mins of prep time and then a waiting period. Sure the re-encoding takes many more hours than the transcode, but it all happens while I sleep anyway so I don't care.

[ddlooping]

adam, just out of curiosity, have you tried v3.0b5 with Deep Analysis?
Also, what do you consider minimal compression?

[adam]

No I haven't had a chance to play with that yet. I knew it was coming out sometime today but didn't realize there was already a download site set up.

In my opinion, as far as transcoders are concerned, minimal compression is around 5-10%, maybe 15%. At these levels I usually can't see any difference between the source and the backup. The problem though is that I can almost never even get close to these types of compression levels when keeping all the extras, which is why I choose to re-encode instead.

[ddlooping]

No I haven't had a chance to play with that yet. I knew it was coming out sometime today but didn't realize there was already a download site set up.

In my opinion, as far as transcoders are concerned, minimal compression is around 5-10%, maybe 15%. At these levels I usually can't see any difference between the source and the backup. The problem though is that I can almost never even get close to these types of compression levels when keeping all the extras, which is why I choose to re-encode instead.

v3.0b5 has been out for months. v3.1 is coming out today.
Yes, I can't see how it would be rare to fit extras as well and keep a low compression level.
It does happen sometimes though, and it could be worth checking.

[nasdravi]

my 2 cents on this:
I get vissible artifacts on a 120 inch projector screen when compression (from dvd shrink) gets bellow 75 - 70 %. They usually occur on fast motion dark sceenes.
cheers!

[Gazorgan]

List price at Target of all places, go figure? It's the guts of those 100 watt 5.1 DVD players, minus the DVD player. I'll post something this weekend with a picture, I've been extremely happy with it.

It had one little bug, in that the digital out has be to channel 2 (it supports 3 channels of A/V and switches), which I messed up and it took an hour to figure out when setting it up.

I'll take a Shrinked movie in 5.1 over the original DVD in TV speaker anyday!!! The first time my wife jumped from something 'behind' her was priceless.

[ddlooping]

"The first time my wife jumped from something 'behind' her was priceless."

[mats.hogberg]

The first time my wife jumped from something 'behind' her was priceless.

Well worth $69.95 at least I can imagine! As Target doesn't have a Swedish branch, what's the make and model of this wonder? Best I've seen yet is some Creative DTS decoder/ 6 ch amp box (I think it's Cambridge something) in the $200 range...

/Mats

[adam]

Right ddlooping, I wrote that as I was leaving the door. I've been using the latest beta since the day it was released, I thought you were referring to the newest release which I am definitely anticipating.

Like I said, I use DVDShrink for certain purposes. Anytime I can achieve what I feel is an acceptable compression level and still keep all the extras, than I use DVDShrink. I also sometimes use DVD Shrink to compress multiangle or otherwise complicated extras which would require alot of manual reauthoring. But when I do so I never go below 85% because beyond this I feel the quality begins to suffer.

[ddlooping]

Ok. got ya.