6 WAV files to one 5.1 AC3... need more help please..

[RogerTango]

ONLY A CLI SOLUTION IS DESIRED, NO GUI OR FRONT ENDS

I have taken a Zoom H2 and created the center and LFE from the files, also split the front channels and rear channels, all with SoX... I am VERY happy with the results.

I have been trying for quite a while but without success, to combine these files into one 5.1 AC3 file for true surround sound.

The files I have are:

frontright.wav
frontleft.wav
center.wav
rearright.wav
rearleft.wav
lfe.wav

Id like to have something like "surround.ac3" for the final encode.

I dont see a way to encode it to an AC3 directly with SoX, I also am not getting proper results muxing all files into one file with 6 tracks with SoX to encode to AC3 with another program.

I am also confused on what order to feed the files to something like ffmpeg to encode to ac3.. Many of my google searches are for nix, or contradicting so I am no closer to understanding than when I started.

I am running Win7/32, I have ready to use: mencoder, ffmpeg, aften and sox.

Does anyone have an example command line I can use?

I am wanting to use my H2 for audio recording, and my MTS for video, combining the two for video with sourround sound for editing.

Many thanks,
Andrew

[dragonkeeper]

ONLY A CLI SOLUTION IS DESIRED, NO GUI OR FRONT ENDS

Take a look at eac3to, it comes with a gui but u can use it CLI via "eac3to.exe"

[RogerTango]

Thanks Dragon, I wasnt thinking in that direction... I actually use eac3to to extract 5.1 AC3 from BD 7.1/5.1, for later muxing (I use HandBrakeCLI for encoding and then mux both into MKV).

I think that would work fine, however I do not know what the expected sequence of input files should be to encode a compliant AC3 file. Do you have any insight please?

I forgot to mention I also have besweet but have not found the information I need in the documentation, either that or I dont understand it well enough to perform the encode.

Thanks,
Andrew

[RogerTango]

Looking at:
http://en.wikibooks.org/wiki/Eac3to/How_to_Use

I was able to encode one AC3 from the mix, however MediaInfo reports the surround.ac3 file is only one channel, and it is "Front:Center", not 6 channels...

Ideas?

eac3to frontleft.ac3+frontright.ac3+center.ac3+rearright. ac3+rearleft.ac3+lfe.ac3 surround.ac3 -448

Andrew

[RogerTango]

I tried with besweet, however my Win7 reports that besweet has quit working, the output file is generated but is 0k in size.

besweet -core( -input files.lst -output 5dot1.ac3 ) -ac3enc( -b 384 -6ch )

AFAIK, I have all the needed DLLs in the same directory.

Andrew

[RogerTango]

Update: Downloaded another version of sweet from here, works with W7...
http://www.softpedia.com/progDownload/BeSweet-Download-1704.html

However voice is like chipmunks, I suspect sampling rate is wrong somewhere, likely in the source.

Ill post back with new discoveries.

MediaInfo does report 6 channel, but until I can play back right, I wont know if I have them arranged in the right input order.

Thanks,
Andrew

[RogerTango]

BTW: my files.lst

G:\ZoomRecordings\5dot1\center.wav
G:\ZoomRecordings\5dot1\frontleft.wav
G:\ZoomRecordings\5dot1\rearleft.wav
G:\ZoomRecordings\5dot1\rearright.wav
G:\ZoomRecordings\5dot1\frontright.wav
G:\ZoomRecordings\5dot1\lfe.wav

[RogerTango]

Still no proper playback of final AC3 with BeSweet, still sounds like chipmunks.

The original record is 18 seconds, the encoded AC3 is 42 seconds.

Im at a loss of what is wrong...

Andrew

[RogerTango]

Found the feed order of files here:
http://forum.doom9.org/showthread.php?s=&threadid=15738#post77320

[RogerTango]

Fixed files.lst:

G:\ZoomRecordings\5dot1\frontleft.wav
G:\ZoomRecordings\5dot1\center.wav
G:\ZoomRecordings\5dot1\frontright.wav
G:\ZoomRecordings\5dot1\rearleft.wav
G:\ZoomRecordings\5dot1\rearright.wav
G:\ZoomRecordings\5dot1\lfe.wav

[RogerTango]

PROBLEM SOLVED!

Changed the file listing filename from files.lst to files.mux and used this command:

besweet -core( -input files.mux -output 5dot1.ac3 ) -ac3enc( -b 384 -6ch )

Works PERFECT!

I now have a 5.1 AC3 from 4 channels as recorded from my Zoom H2!

The center and LFE are "pseudo", as they were generated from the front and rear stereo files.
The center was generated from the front left and right with a 1khz highpass filter (Using SoX)
The LFE was generated from front left and right, and rear left and right, with a 200hz lowpass filter (using SoX)
Thus, the LFE will be all sounds, 200hz or lower, from any of the 4 recorded channels.. all "booms and
bangs" will be though the "subwoofer".

Next: Build a GUI that will take the Zoom H2's two WAV files and generate a batch file for you
to do your own conversion.

Cheers,
Andrew

[Cornucopia]

@RogerTango,

I'm glad you found a solution. However, what you're creating won't always play correctly as you have set it up.

If your recording is truly Quad (LF, RF, LS, RS), you shouldn't be using AC-3's 5.1 channel layout, you should be using it's 4.0 channel layout.

As it is, a setup with full range front speakers (with or without subwoofer) will give way too much bass, and without a center speaker would give 150% the volume into the remaining front speakers, as that's how it is set up to "fall-back" as a downmix in those cases.
Staying 4ch->4ch will still correctly decode to whatever your speaker arrangement is at playback time. Stay "discreet", not "pseudo", and it ought to work better for you (and others).

Scott

[RogerTango]

Thank you Scott for your input. I will move forward with testing this configuration and examine the results.

I will be testing it with video soon, and will be playing it back on my WDTV with a true 5.1 surround sound system.

I will post back findings when I have them.

Thanks again,
Andrew

[RogerTango]

Right now, the center channel is a mix of front left and right, with a cutoff of 1khz and volume reduced to .25.

Would you suggest I change the settings to be front left and right combined, and front left and front right to be
reduced in volume by .25 and apply a cutoff?

Ill know better when I start testing, but wondered what your thoughts were...


Andrew

[dragonkeeper]

PROBLEM SOLVED!

Changed the file listing filename from files.lst to files.mux and used this command:

besweet -core( -input files.mux -output 5dot1.ac3 ) -ac3enc( -b 384 -6ch )

Works PERFECT!

I now have a 5.1 AC3 from 4 channels as recorded from my Zoom H2!

The center and LFE are "pseudo", as they were generated from the front and rear stereo files.
The center was generated from the front left and right with a 1khz highpass filter (Using SoX)
The LFE was generated from front left and right, and rear left and right, with a 200hz lowpass filter (using SoX)
Thus, the LFE will be all sounds, 200hz or lower, from any of the 4 recorded channels.. all "booms and
bangs" will be though the "subwoofer".

Next: Build a GUI that will take the Zoom H2's two WAV files and generate a batch file for you
to do your own conversion.

Cheers,
Andrew

Glad you got it worked out, but i have a few reccomnedations that may improve sound field.
* Center place a bandpass filter just inside the vocal range (80 to 260 hz should do nicely)
* LFE low pass filter is good a bandpass would be better, you want to filter out any sub-sonic frequencies that could damage your sub also without a reduction in volume the LFE channel may over take the rest of the speakers a 25 to 50 % reduction should be all that's needed.
* Front channels reduce volume by 25 % or so most dialog should seem to come from your center channel, but if any loud noises occur in either the left or right speaker it will give the illusion of panning from the center channel to that speaker.
* Rear channels are for fill they should be bit softer than your front channels, maybe 25 to 50% lower volume than your front channels.

You'll have to play around a bit to get the right mix, but you can achieve some very impressive results.

[Cornucopia]

Before I give any more recommendations, it would clear some things up if you explained how you set up your mikes with you ZoomH2.

********************************

The thing is, all that pre-mixing that you're trying to accomplish may be unnecessary if the Channel Type is set correctly, as AC-3 is smart about how to modify the channel balances during playback.

For example, LFE is NOT, I repeat NOT for bass/sub portions of the main signal. Just like its name, it is for "Low-Frequency EFFECTS". If you don't have low-frequency effects, it doesn't even need to be used. The LF, C, RF, LS and RS channels are all full bandwidth chanels. But these don't always equate to the channels used in playback. Bass sounds will get sent to their normal channels, unless you have a subwoofer. In that case, the receiver re-routes bass sounds to the subwoofer and if the main speakers are satellites and not full-range speakers (very common setup), it'll also re-route their low-frequency portion to the subwoofer.

So if you were to create an ADDITIONAL LFE signal, built from bass feeds from the main channels, on playback your subwoofer would probably get BOTH the full LFE signal, and the re-routed bass from the main channels. In effect, it would DOUBLE the loudness of the low levels - BAD!

That was one of a couple of examples that show how one really needs to understand and think carefully about channel/signal placement in multichannel files, particularly AC-3, which has a number of built-in features to accommodate multichannel.

Scott

[RogerTango]

Scott,
Very informative... also thanks to Dragon for the education.

So in reality, I *could* leave the LFE band as blank, if I were using a receiver?

The situation is, I am NOT using a receiver.... rather a simple 5.1 amplifier so I dont *think* there is any processing or
re-routing going on, but it does beg further experiment to determine!

Im back to work, only had Sunday off (drats!) so it may be next week before I can test further. Id like to get some recordings of
passing traffic and some nature recordings to play with. I hope to post back with results and *SAMPLES* soon!

Thank you both very much for your time!
Andrew

[RedDwarfer]

This is a bit of an old thread, nearly a year old so RogerTango probably got it fixed in the end.

I needed to do the same thing myself and after messing with Besweet and similar utilities, finding out that BeSweet has dropped AC3 support and that it didn't work properly anyway, therefore I needed another solution.

I found that WAVtoACEncoder is simple to use and can use some SIMD CPU instructions to speed up the encoding, nothing new, only SSE3 but anything that helps is useful. It allows the channels to be mapped easily so that the mono Wavs are all in the correct place.

http://code.google.com/p/wavtoac3encoder/downloads/list