AC3 audio sounds horrible... low volume and hollow, wav grea

[rastoma]

I am taking wav files that have been extracted from avi's and mpeg's and converting them to ac3 to make a DVD compliant disc. I have extracted the audio using vdub full processing mode and also have tried avi2wav. Both yield great sounding wav files. When I convert them to ac3 they sound horrible on the finished product.... hollow sound.. very low volume. I have used besweet and followed every guide I could find... I tried last night Vegas 4 to convert to ac3.. exact same effect.

It sounds the same on any of my PC's or my TV. I have an XP2000 w/ 1 gig RAM. I am using TMPGENC DVD Author.

Any suggestions or are there other DVD compliant sound formats I can use? I've tried in DVD Author just using the sound from the mpg that I have reencoded and it sounds better but volume is still a lot lower than the original and a lot of times it's out of sync.

edit - forgot to mention I have tried taking the wav file and running through Goldwave to increase the gain/volume which sounds great after it does, but still sounds horrible, horrible after converting to ac3.

[wwaag]

I had the same experience with Besweet some time ago--tried all kinds of things to correct the low volume, hollow sound. No luck. If you search through some of the older threads, you'll find that it's a commonly reported problem.

My solution--forget about AC3--at least for the moment until there is good reasonably priced software. I just stick with MP2. Even though it is technically "non-compliant" according to the NTSC DVD standard (it is within the PAL standard), it works on the vast majority of players--certainly on the ones I've tried. Plus MP2 encoding is included in most enocders (CCE, MC, and Tempgen) so there are no extra steps involved.

Just my opinion.

wwaag

[rastoma]

will it play on a ps2 ?

[wwaag]

Sorry, don't have a PS-2. Suggest you try it with a RW disk--that is, if a PS-2 plays rewritables which again I don't know.

wwaag

[Megahurts]

rastoma

Just a guess but sounds like the left channel is out of phase with the right. To test this theory, load the wav file in GoldWave, choose effect > stereo > channel mix > presets > mono mix. Play it back. Is the volume lower and hollow? If so you'll have to invert either of the channels but not both.

Hopes this helps

Chas

[mkelley]

How are you extracting the audio?

PCM files that have not otherwise been compressed first will convert just fine to AC3 using BeSweet -- the infamous "low volume" problem with BeSweet involves compressing already compressed sound (like using an MPEG sound file). Obviously if you create a .WAV from an already muxed MPEG sound file you have that situation, but you shouldn't if you are just ripping the sound from the AVI (using, for example, AVI2WAV).

[wwaag]

In my attempts to use Besweet, there was still the low-volume problem even from directly extracted WAV files. The extracted WAV files sounded fine, but when converted, there was alwys a big-time loss of volume and a somewhat hollow sound. Moreover, you couldn't compensate simply by turning the volume up--it just sounded different. After trying quite a few suggstions from other posters, I finally abandoned ship since the resulting MP2 files sounded as good as the original WAV files and they worked in all of my players.

wwaag

[Metaluna]

I used to think it was just a problem with BeSweet until I tried out the AC-3 encoder in Vegas 4.0 and found that it had exactly the same low volume problem, even with a normalized audio file as input (it would sound exactly the same as the non-normalized file). Then I tried the same file with Soft Encode and it sounded fine. After comparing the settings of the two commercial encoders, I found that Soft Encode had an option checked that Vegas did not. I forget exactly what the option was called, but it was something about setting a room monitor level to 105dB. I believe it sets a flag in the AC-3 stream that gives some kind of absolute volume level reference. After checking this option in Vegas and re-encoding the audio volume sounded fine. I bet if the BeSweet encoder allowed you to set this flag it would fix the audio level problem.

[rastoma]

thanks all...

mkelly,

i am taking avi's and mpegs and converting to dvd and i get the same result if i extract a wav from an avi and convert to ac3 or if i extract sound as a wav from a mpg and convert to ac3.

in either type of file the wav sounds great.. loud and clear. i have also tried to run the wav through gold wave and double the volume before converting to ac3... same affect.

megahurts,

i will try your suggestion.