Help Applying Dynamic Range Compression to AC3 file

[Xplorer4x4]

I want to try applying dynamic range compression to an AC3 using BeSweet(1.4 and 1.5b31) with BeLight(0.21) but keep getting errors. Here is the log:
http://pastebin.com/PiEvnxpq

So I tried eac3to and more gui but can't figure out how to apply dynamic range compression to it. Is it not in the GUI?

The bottom line is I want to apply dynamic range compression to ac3. My media player(WD Live) already down mixes multi-channel audio 2 channel audio but in the interest of testing, I also wanted to down-mix the channels. Can any one recommend app with a GUI to do all this?

[tebasuna51]

The error is here: -ac3enc( -b 684 -intel )

I can't understand how you can put bitrate 684 with BeLight.
The max allowed value is 640, but for stereo you can use 192.

The AC3enc isn't recommended but if is for testing ...

With eac3to you can't use DRC because is not recommended for transcode.

You can use also BeHappy-AviSynth, Belight can work but use last versions:
http://kurtnoise.free.fr/BeLight/BeLight-0.22_RC1.zip
http://kurtnoise.free.fr/BeLight/bsn_20070513.zip
and Aften encoder instead AC3enc.

[Xplorer4x4]

As for the bitrate, thanks for pointing that out. This must be a bug in BeLight I moved the slide from 640 to 576. and it started encoding. However won't setting it to 192 significantly reduce the audio quality or will DRC butcher the quality as it is.

AC3enc - I saw this mentioned in the FAQ, but it wasn't elaborated on at all. I have also seen this in a few threads on my quest for an answer as to why the encode failed. Is it because AC3enc is old and out dated and/or simply never matured in to a good encoder?

I will try your recommendations though. Thank you very much!

[tebasuna51]

DRC reduce the audio quality of course, and for stereo you can go until 256 Kb/s but use a greater bitrate is useless.

AC3enc is old and out dated and always reduce the input volume by -6 dB

[Xplorer4x4]

Thanks for all your help! BeHappy is exactly what I need! Very customizable but, yet, user friendly. I read the read me in the encoders folder and found the binaries for Aften. From there it is smooth sailing. Getting ready to test 2 videos to see how they work. May take a little tweaking but this is exactly what I needed so thanks again!

[Xplorer4x4]

Ok I had a follow up question and I felt it better to post it here then a new thread..

Sometimes when I measure the RMS scope of a segment of voice only audio, the RMS level is above 31db which is the max that can be set in BeHappy when using Aften. If we are supposed to set the Dialog Normalization to match the RMS level what would be an idea level to set this to if say the RMS level is 35db?

[tebasuna51]

-31 dB is the limit of AC3 specs, then you can't go below 31.
Maybe you need amplify your record to match Dolby specs.

BTW, I never use other DN than -31 dB.

[Xplorer4x4]

Ah I keep forgetting we are working on a negative scale here, so it make since bumping the volume up would be a good idea. A hassle as it adds another step but I see what you mean. Thanks for your follow up.

What about MP3? I realize there is no such thing as dynamic range compression for MP3 but is there anything similar or would it be better to convert to AC3? If converting to AC3 from a lossy format to lossless, assuming this is the best route to go, what kind of bitrate should I use for AC3 when coming from MP3s with a bitrate of 128 and 192 ?

[tebasuna51]

I think DRC is obsolete, was a aid to old amplifiers without big process capabilities.
Modern amplifiers/receivers can do the same thing in real time: Night modes and similar.

Convert MP3 to AC3 is a bad idea.

[Xplorer4x4]

Not to nitpick but do you mean DRC not DNR right? Just making sure we are on the same subject. ;)

As for compression, I do not have a amplifier but rather just a TV with not way to set DNC in the options menu. The biggest reason I need DNC is because I live in an apartment complex, so I if I decide to watch a movie at 3AM I prefer not to disturb my neighbors.

I realize AC3->MP3 is not the best choice. It is not my ideal solution so this is why I wondered if it(or something similar) could be done in an MP3. As it is I do not know what else to do besides convert MP3 to AC3. If you have another solution, by all means please let me know. I would be happy to here your suggestions because I cant think you, and your friends, enough for your work on BeHappy. It has done an amazing job on my AC3 files so far!

[tebasuna51]

Yes, my mistake , I was talking about DRC (edited).