Hiss removal from AC3 file without converting it to WAV?

[Turbo Sensonic]

My friend gave me a music DVD which has originally been transfered from VHS to DVD. However, the audiotrack contains a lot of hiss during the concert. Therefore I demuxed the DVD on my computer's harddrive and thus I now have separate m2v video file and ac3 audio file. I tried to search for the program which would enable me to remove the hiss from the audio track (i.e. noise suppressor, noise gate etc.) without converting ac3 file to wav.

The only one I could remember was (Ahead) Nero's wave editor with ac3 plugin. OK, that worked great but then I would have to burn the audio track onto CD-rom because I wasn't able to save the modified file on my harddrive.

So my (stupid) questions are:

1) is there a way to save the modified audio track onto harddrive if I'm using Nero's wave editor? Since the track is 84 minutes long, it's very hard to fit it onto CD-rom.

2) are there any (freeware/shareware/payware) programs which can be used to remove hiss noise from ac3 file without converting it first to wav?

I'd really appreciate if someone could help me with this matter! Thx in advance!

[Soopafresh]

Converting it to wave should be the least of your worries. The change to the sound from noise removal will have a much bigger effect on quality than AC3-WAV conversion. Hiss is a difficult and complicated type of noise to remove - the results are almost never great.

[AlanHK]

It's impossible to do much with an AC3 with any free tools, except cut and perhaps join. I don't know of anything that can even just change the colume, though that should be possible.

Nero is not working on the AC3 as such, it's expanding it (to wave probably) and compressing it back to AC3. I guarantee this is what it's doing. Look for a very large temporary file while you have the AC3 open.

So given that, if you want to do anything to the audio, first convert to WAVE yourself.

Use Ac3Tool or another tool listed at https://www.videohelp.com/tools?toolsearch=ac3

Then you can try various filters, eg with Audacity, to remove the hiss.

Finally save as WAVE and convert that to AC3 with one of the tools listed (ffmpeggui, for instance).

[hotwings]

yeah i agree, most editing programs won't work on a compressed format. if they do they most likely actually convert to wave or some other uncompressed form as an interim step that may or may not be hidden from the end-user. Hiss is a bitch to get rid off. I use cooledit to do that and it's always a balancing act, there's usually some residual gargly noise deep in the background left in place of the hiss. How much of the gargly noise (or whatever you choose to replace the hiss) left behind depends on how many decibels you actually noise reduce.

[Turbo Sensonic]

So given that, if you want to do anything to the audio, first convert to WAVE yourself.

Use Ac3Tool or another tool listed at https://www.videohelp.com/tools?toolsearch=ac3

Then you can try various filters, eg with Audacity, to remove the hiss.

Finally save as WAVE and convert that to AC3 with one of the tools listed (ffmpeggui, for instance).

Yes, I know the procedure. OK, if there's no way to reduce hiss from the original audio file, then I have to use Audacity or Soundengine. I already have the file converted from AC3 to WAV on my harddisc so that's already a good start.

[Turbo Sensonic]

OK, I started to use Audacity's noise suppressor function.

First it tells you to find a certain spot in your audio file to check the status of noise/hiss and after that you can adjust the level of noise reduction.

However, the audio track of my concert DVD is 1 hour 24 minutes long and when I'm trying to get a "preview" of the audio track, all I can hear is 1 second segment of the audio track starting from beginning and that's it. So how to hear a proper "preview" of the audio track with Audacity?

With Soundengine and Wavepad Audio Editor it works. The only problem is that aforementioned programs tend to use a noise gate which is not appropriate for my audio track. I'd need to cut off the noise/hiss completely between the songs and also during the songs. I think that the noise gate is only meant to reduce noise between the songs.

So what's next? Should I try to EQ the audio track and reduce the gain of the hiss frequency?

And once again, I'd be very pleased if somebody could give me valuable hints! Thx in advance!

[Soopafresh]

Turbo Sensonic - Hiss consists of many, many frequencies. Hard to cut hiss without everything immediately sounding bad. The only thing I can think of (and I've never tested it) is to duplicate the procedure used in Dolby Noise reduction back in the days of cassette tapes -

Performing dynamic compression for encode
Performing dynamic expansion for playback.

Recording the playback. (or saving the file with the expansion effect applied)

Post (up to 2mb) of a sound fragment up here and we'll try to help, or tell you to forget it

[Turbo Sensonic]

Turbo Sensonic - Hiss consists of many, many frequencies. Hard to cut hiss without everything immediately sounding bad. The only thing I can think of (and I've never tested it) is to duplicate the procedure used in Dolby Noise reduction back in the days of cassette tapes -

Performing dynamic compression for encode
Performing dynamic expansion for playback.

Recording the playback. (or saving the file with the expansion effect applied)

Post (up to 2mb) of a sound fragment up here and we'll try to help, or tell you to forget it

I've achieved quite good results with the wave editor of Ahead's Nero. Quite unbelievable, but it's the easiest program to work with and you'll even get pretty decent results with it 8) I presume that its "noise removal" effect makes the similar kind of effect like Dolby Noise Reduction and not a "noise gate" effect which I don't need.

The only problem is that the concert lasts 84 minutes so either I should have 90 minutes CD-R or figure out a way to save the modified WAV -file on my computer's harddisc.

[lordsmurf]

Goldwave and SoundForge gives the best results in my experience. Goldwave is very heavy-handed, while SoundForge can be very minute.

[redwudz]

Turbo Sensonic, if you were using the 'Noise removal' function with Audacity, it doesn't seem to work too well with hiss. It's more for repetitive sounds, while hiss is just wide spectrum noise. I've had better luck with the high/low pass filters. But any filtering removes something, so often you just have to compromise with a 'slightly' better sounding file.

I would also work with just a short representative piece of the audio file, lots faster to hear the results.

I have my suspicions that the excess hiss may be the result of someone trying to apply filtering before or boosting up the high frequencies to try to make it sound better.

[Turbo Sensonic]

OK, now I managed to get the audiotrack in "so and so" shape so the majority of hiss is gone. OK, that's good.

So then I converted WAV back to AC3 file and tried to remux the DVD with Muxman. Muxman didn't accept the audiotrack but announced that there's a problem with the track

However, I can play the track without any problems and the result was quite good. Now I only have to figure out what went wrong during the conversion from AC3->WAV->AC3 since it doesn't work with Muxman

[gadgetguy]

What did you use to convert back to AC3?

[AlanHK]

So then I converted WAV back to AC3 file and tried to remux the DVD with Muxman. Muxman didn't accept the audiotrack but announced that there's a problem with the track

Muxman should give some kind of error message, in c:\muxman.log in my version.

Did you use 48000 sampling rate when making the AC3?

[Turbo Sensonic]

Muxman should give some kind of error message, in c:\muxman.log in my version.

Did you use 48000 sampling rate when making the AC3?

Yes, I did.

[Turbo Sensonic]

What did you use to convert back to AC3?

I used ffmpeggui for WAV->AC3 conversion and before that I used Ahead's Nero AC3 plugin to convert file from AC3 to WAV.

[rkr1958]

Goldwave and SoundForge gives the best results in my experience. Goldwave is very heavy-handed, while SoundForge can be very minute.

However, SoundForge ($400) can be very heavy on the wallet versus Goldwave ($45).

[gadgetguy]

I've heard (read) other people complain that AC3 files from ffmpeg are a problem with Muxman. Try encoding to AC3 using something else, like QuEnc (free).

Edit: My mistake, it's BeSweet that people have complained are non compliant, not ffmpeg. Still, it might be worth trying a different AC3 encoder.

[AlanHK]

Muxman should give some kind of error message, in c:\muxman.log in my version.

Did you use 48000 sampling rate when making the AC3?

Yes, I did.

And what about Muxman's log file?
Did it specify the error?

[Turbo Sensonic]

And what about Muxman's log file?
Did it specify the error?

No, I never got that far.

I added video file (m2v). It went OK, but when I tried to add modified AC3 file (or even a WAV file which was converted from AC3 to WAV with AC3 Tools), Muxman announced:

Multiple File Open Status:
0 files accepted, 1 file(s) rejected

Very strange indeed...

[AlanHK]

If you're making a DVD with one "feature", no menu, try Rejig.
Very simple and fast.
Less fussy that Muxman.
If it fails too, there really is a problem with your files.

[Turbo Sensonic]

If you're making a DVD with one "feature", no menu, try Rejig.
Very simple and fast.
Less fussy that Muxman.
If it fails too, there really is a problem with your files.

OK, I didn't try Rejig yet, but instead of that I tried Ifoedit. I didn't have much time on this morning but I managed to try whether the program would accept the audio file I had converted. And yes, it accepted it Now I only have to try whether Ifoedit will remux the DVD and then I can put it "back" to original DVD menu with Vobblanker

Ifoedit's website doesn't seem to work anymore, which is a pity because it contained very neat tricks & gimmicks one could do with that program Does anybody know any good website which has similar kind of support for Ifoedit?

[Turbo Sensonic]

Back to this topic:

OK, now I succeeded to remux video and audio tracks to DVD with Ifoedit but now the audio track I modified is out of sync with video. I tried to demux the DVD again in order to find out the delay. Well, both Rejig and PGCdemux announced that there is no delay at all...

How to fix audio/video delay in this case?

And as always, thank you in advance to everybody who can help me with their knowledge!