Loudness of AC3 audio

[F u r u y á]

Why is it so low? I had to put my TV volume at max! To solve this I used Soundforge and raised the volume by 1000% (the max possible) and it is still a bit lower than some mp3 I have here, but it's ok now. After that change Soundforge showed the sound as 20dB, original loudness is 0dB!!


Just for information purposes, the audio is 5 chanel and I used Goldwave to extract that audio from the avi, it was the only way I could do it, with VirtualDub I got the error "No audio decompressor could be found to decompress the source audio format (source format tag:2000)", despite I have AC3Filter codec. I was wondering if that loudness issue is normal or if I made something wrong.


edit - more information: In Goldwave, I converted that AC3/5 channel/48KHz to 44.1KHz/Stereo/16bit

[Sakuya]

You don't have to do all that stuff if you just want to listen on the computer. Just use the Gain feature in AC3Filter. I believe you can do that by right-clicking on your video player while playing the video and then selecting codecs, or something like that. Make sure to set the number of speakers you're using! If you select 2 speakers, then it will adjust for you so you might not have to use Gain at all. Just leave your normal computer volume at normal (remember to do this first!).

[F u r u y á]

But I don't want just listen in computer, I'm doing this to enconde with video and burn in a CD to watch in my DVD Player. And to do this I need to extract the audio and convert it because I don't have 4.1 system or a Home Theater, and because it's recomended when using TMPGEnc and all that stuff

[guns1inger]

Your player will play back 5.1 as 2.0. It's in the specs that it has to do this. As for it being too low - DVD Audio has a much hifgher dynamic range than CD audio or analogue TV broadcast audio. This means the difference between someone speaking in normal tones, and the sound of an explosion, is much greater. This adds to the realism. While this can mean many that speaking parts can seem very quiet, I have never found a disk yet where I had to push the audio that far up. I suspect your TV volume range is too low to begin with.

Some players have a facility in the settings to compress the dynamic range on playback, to bring the quiet and the loud moments closer together in volume. Check to see if yours has it. It could be called DRC, ARC or midnight listening mode.

[F u r u y á]

No, my TV has a large range of volume, the problem is with the source video (Xvid/AC3), when I play it is already too low the volume

[NiteLite]

Every DD5.1 DVD I have backed up from an original copy is from -3 to -12 db lower than the original. Sometime last year I read a very long thread (another forum) invloving some software developers...lets use Decryptor or DVD Shrink for example only...When using one to encode the volume is always lower.
The conclusion was never reached (at that time) as to why. The program developers could not see any reason why their programs would have any affect on the audio.
I dont either but something sure does.
If you find a "why" it does this post back.....thanks
NL

I usually have to raise the volume on my receiver 6db -average-. Not a problem but still curious.

[garryheather]

Does your TV have an audio level adjustment on the source you've connected your DVD player to ?

Mine does - it allows you to reduce the volume on one or more inputs with regards to the others if one source (eg the tuner) is significantly louder. You may find your source in question is set too low if you have this feature.

[F u r u y á]

But that source I play in my computer and it's already low volume.

Well.. I will assume that the problem is with this particular video. Next AC3 5 channel videos I download, I'll check if it have that same problem. Thank you all for helping

[guns1inger]

If you download then you take you chances that you will get something not up to the original. If the source volume is too low, then you need to demux all 6 channels out to mono wav files, increase the volume in each, then reencode as AC3 5.1. You can probably use Besweet and goldwave to do this. You risk loosing some audio quality through this process however.

Nitelite - I'd be interested in reading that post, given that DVD Decrypter only rips, and DVD Shrink doesn't touch audio.

[NiteLite]

F u r u y a

But that source I play in my computer and it's already low volume.

Well if the source if already low volume then as guns1inger stated you have options.
I thought you were talking about your purchased pressed DVDs encoding and written back to a DVD blank and then experiencing the low volume.

guns1inger, man it was a while back but one of the authors was involved with the discussion. Maybe Shrink. I will look for the forum if I can remember what it was. I was new at the time and just reading and then found this site which was more open to learning.
If I can remember or search and find I will be glad to pm you the link as this thread probably will be long gone...but I will look.
Basically it was as I stated. Started as a "why do my DVDs play at a lower volume after shrinking and encoding?" As several chimed in and stated "I have the same problem." the thread went on to look at different possibilities. Again the author stated that the program had no effect on the audio...however the question remained. "I have a pressed DVD that I play at say -16dbs (comfort zone) and after backing it up now I have to raise the volume 6 or more dbs to have the same volume.
As I stated there was never a conclusion as to why. I dont remember visiting that thread again. If it comes back to me or I find in "Favs" I will let you know.
NL

I think Decryptor rips and writes but even ripping and writing using another program a transfer is made. Also with Shrink. It may not touch audio but when the ears and a db meter confirm the outcome...it is a mystery. I admit to being totally confused as to how also.
NL

[Nilfennasion]

It is a common misconception that Dolby, or DVD audio tracks in general, are consistently recorded too low. The reality is that everything else is recorded too loud. If you are going to adjust the volume of the audio on a video you encode to DVD, at least make sure to get some objective standard to calibrate the audio to, so you don't wind up destroying the audio's fidelity or blowing your eardrums out.

[MOVIEGEEK]

@NiteLite,
Yeah I read the same topic on www.dvdshrink.info
I also get a reduction in volume from DVDShrink when I transcode 5.1 but not with 2.0.

[NiteLite]

@NiteLite,
Yeah I read the same topic on www.dvdshrink.info
I also get a reduction in volume from DVDShrink when I transcode 5.1 but not with 2.0.

MOVIEGEEK...Thanks so much for remembering that and posting. I just could not remember. I did not even have that forum in my Favs.
guns1inger...thats the forum. Sorry I dont know the thread but sure it had something to do with "volume."

Nilfennasion........ Dolby and DTS have strict standards for audio when used on DVDs. It's not that DVDs are recorded too loud. (maybe CDs)
While DTS has a -0 db offset, Dolby requires a -4 db offset. This is one reason some think DTS sounds better than Dolby because it is recorded 4 db louder and louder must be better...ok we know better. Others realize that it may be that less compression is used and a fuller sound is heard. I say it still comes down to the mixing engineer.
But back to the main point. Something occurs when using some (maybe all) software but Shrink for sure, (and I only say shrink because it is my choice of software most used.) that reduces the volume from the original pressed DVD to the recorded DVD blank media. MOVIEGEEK and I'm sure many can confirm that point.
My High-End Denon receiver uses a db meter for volume and I also have a db meter. I can truly say there is a difference.
Sure I can live with it but it's an anomaly.... I also agree that with CDs there is no standard...louder is all the norm. But with DVDs their are standards even if not always followed exactly.

MOVIEGEEK, thanks again.
NL

[guns1inger]

I have just been reading through the many and varied posts on the topic. From what I can see there, the following seems to be universal

1. DVD Shrink does not touch the audio other than to remove it if asked.

2. It does not seem to affect everybody, or be consistent in the degree of change

3. The issues were raised for early versions of Shrink, but have not been raised in some time

4. There does seem to be an issue with the way some players read audio from DVDR disks.

I must admit that I have not experienced this sort of problem, and have backed up many disks with Shrink and Rebuilder. I'm not saying it doesn't happen - the evidence proves that it does - however I would lay the blame at the feet of the player manufacturers and the way they read DVDR disks. I have seen too many anomolies between players playing the same disk to believe otherwise at present.

[NiteLite]

guns1inger,
Good points made even though
#2 - could be sujective unless using a calibrated measure of test.
#3 - I think people just learned to live with it (or forgot about it) as no conclusion was finalized.
However, #4 is a point that I personally had not considered; That the read of the audio of a DVD player with a pressed DVD and the read of a DVDR may be different. Point to ponder for sure.
As I said above I made many tests with a calibrated db meter to prove what my ears were telling me - basically a DVDR 5.1-audio was about -6 db lower in audio output with some as little as -3db. Hardly noticable to someone that has numbers 1 - 10 on the volume knob or a level meter across the TV screen.
Anyway, thanks for the input. Piont #4 really gives me something to go on. At the least I have a reference to research some when time permits.
Thanks again,
NL

[guns1inger]

I guess you have proved #2 yourself, with the measured changes being in a range, rather than consistent amount.

#3 - fair call. It's amazing how much people will put up with, so something this small could well die off as an issue.

My amp goes up to at least 50, although to push it that high (or higher if permitted) would cost me a set of speakers and a few windows. I know my general listening volume, and this doesn't seem to vary much between commercial and backup disks. -6Db is in fact a fairly noticable drop, so I suspect I would have picked it by now. That said, maybe I'm going deaf in my old age.

I'd be interested in what you find if you get the chance to dig deeper into this.

[Nilfennasion]

Nilfennasion........ Dolby and DTS have strict standards for audio when used on DVDs. It's not that DVDs are recorded too loud. (maybe CDs)

What I said/meant was that people complain that DVD-Videos are too quiet. I have reviewed one DVD here in Australia where the distributor decided to make the average volume louder, just to see how people who made such complaints would react. It hurt my ears to listen to. In fact, I had to bring the volume down at least five dB to get to a point where I was comfortable.

As to the point about DTS vs Dolby, yes it is true that a lot of the performance comes down to the sound engineer. That disc I just mentioned was painful to listen to not because of the compression, but because the sound engineer was basically an idiot. But I would also venture that DTS does give the engineer more to work with. The DTS soundtrack on the Region 4 PAL release of X-Men is a very good example. The subwoofer output is far better integrated into the soundtrack, sounding more like the low-surface rumble the director had apparently intended than the congested mechanical fart of the Dolby soundtrack.

For my part, I cannot say I have genuinely noticed a volume difference after transcoding with DVDShrink. Not when I transcode straight from disc, and not when I transcode from a file/directory on my hard drive. I think I would have noticed this considering I have done over 300 discs by now. But, just out of curiosity, does enabling the logical remapping of enabled streams affect the audio at all?

[MOVIEGEEK]

"But, just out of curiosity, does enabling the logical remapping of enabled streams affect the audio at all?"

Good question,I've never tried it.
Come to think of it the volume problem occured when I used DVDShrink 3.05b,I just checked a DVD I backed up with v3.2 and it's fine.

EDIT:This explains logical remapping: http://forum.digital-digest.com/showthread.php?s=&threadid=45228

[NiteLite]

guns1inger & Nilfennasion,
I hope my posts are not perceived as challenging. I agree with you guys . Only exception is the lower volume I have with my DVDR's.. I appreciate your input and experiences as they are helpful and insightful.

I have never enabled the "logical remapping of enabled streams."
Nice link Moviegeek...It did not appear to me it had any effect with audio on or off.(?)
Also I have the situation with both versions of Shrink. I guess it is still an anomaly that will retain it's mystery.
I just found a DD5.1 disc that had a -0db offset and backed it up and found it very close to the original. So maybe the DD -4db offset standard is a factor.
Who knows.
Any way I appreciate the input everyone and I hope this has helped "F u r u y á", thread originator.

Nilfennasion...I hate the limits of DVD backup space often forcing me to choose DD over DTS. DTS is my choice of compression. For a real treat and to hear the limits of both formats I listen to high resolution uncompressed SACD or DVD-A. Now thats good sound...again depending on the Engineer.
Regards,
NL

[Nilfennasion]

I hear you on that one. One title I recently backed up gave me a choice of either keeping the DTS and compressing the title down to 80.something percent, or losing the DTS and having space to spare. Given the quality the Dolby soundtrack had, I decided to keep the DTS. In extreme cases, where a film is cut down to 60% or less with DTS, I will even consider using a DVD+R DL, now that I know I can bitset them and make them work on my existing player.

As far as the original problem goes, without the logical remapping possibility, it has got me beat.

[F u r u y á]

Well, I saw I touched a sensible point.

So the veredict may be that the problem resides on econding, when the guy who encoded the movie used the DVD Shrink "bugged" version. Once more, thanks all for helping