hello. i'm trying to convert some of my movies to Divx with the best possible audio possible. instead of making mp3's for my avi files, i'd like to make ac3 audio for them. some of them are in 5.1 surround sound. some might ask " why don't u just use the ac3 files that came on the original movie?". well the original ac3 files are very big and i'd like to maintain the 5.1 surround sound with smaller ac3 files. [like 256kbps maybe].
i've been using Headac3he to convert the original ac3 file to a WAV file. this seems to work but, i'm not sure i created the wav file from the original ac3 file correctly. in the option section on Headac3he, i chose 6 channels. this made a much bigger wav file then just selecting surround 2 [which i guess i'd use for converting over to mp3 or ac3 2/0]. i've read that selecting surround 2 stores the surround sounds [frequencies] to the left and right channels for later use. i'm not real sure on that.
i've also used besweet and its gui to create ac3 files [2/0 and 5.1] but they sound very low compared to the original. ffmpegui does the same thing [low volume] and only has an option for 2/0 ac3. are the ac3 encoders in ffmegui and besweet any good? should i use them to make ac3 files?
i read in a besweet faq that the ac3enc.dll included in the package is no good and should b used for testing only. is this true?
i also loaded the wav file that was created from the film's original ac3 file into virtual dub, then chose full processing mode, and chose the ac3 acm codec inthe list. it seemed to work and the volume was pretty much close to the original. but i wonder in the back of me mind if it actually re encoded the wav to a proper 5.1 surround sound ac3 file.
am i using the correct software for what i need to do?
am i heading in the correct direction for creating correct 5.1 ac3 files?
is it possible to make a wav file [one not 6 mono wav files] with 6 channels of sound stored in it, so it can later be recompressed correctly to 5.1 ac3 files?

thanx for taking the time to read this thread and i'd appreciate any helpful advice..........thanx! :confused:

Aften is a very good free AC-3 encoder. However any bitrate lower than 384 kBit/s can't encode 5.1 with good quality.

yes, it's not a good AC3 encoder.



It is a good valid Ac3 file.



It wouldn't recommend you to use AC3 for less than 384 kbps.



yes, you can create the six independant channels and mux them together with wavewizard or use software like Vegas that can export in multichannel.
And lossless formats like FLAC or the MPEG-4 Audio Lossless Coding (MPEG-4 ALS) can store multichannel audio.

I would recommend you to use AAC if you want to use 256 kbps for a 6-channel audio file.

thanx guys for the quick replies. this has helped out alot with all the reading i've done in the past 48 hrs.
i think i'll take the six individual wav files i created with besweet and create DTS audio for me movies for now.
one thing tho...... when i created the six individual files with besweet i noticed something about the LFE channel. i opened all the individual wav files with a wav editor to see if they were all different on the spectogram and they were but the LFE looked as if it had no sound on it. it was more or less a straight line across the graph. does this sound right for an LFE channel?
i played that one channel and listened very carefully to the sub and couldn't hear anything...... does besweet mix the LFE channel into the surround L/R channels?
thanx again.

The LFE channel is for extra bass effects. Is not mandatory to use it when creating surround sound and its use is more common in action/adventure films, where an extra bass is employed for special FX (like rumble, earthquakes, explosions, landslides, music).


Besweet will mux the LFE into the Front channels if instructed so.
Besweet options allow you to mux or not the LFE to the Front channels and specify the gain, when downmixing from 6-ch to a lower number (i.e. 2-ch).
The info in the LFE channel (wrongly called "subwoofer", as it is not) is frequency restricted. It goes from 20 to 180 Hz approx and if your speaker's frequency response can't deal will these freqs, then you won't be able to hear the sound from the LFE.

Later, dude