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Old 11th July 2006, 12:23   #22  |  Link
tebasuna51
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Join Date: Feb 2005
Location: Spain
Posts: 6,890
After the test I think Aften is the best free ac3 encoder.

I want compare the options with the old reference encoder Sonic Foundry SoftEncode (in speed Aften is clearly the winner, Softencode need hours to encode a 6 chan 130 min long):

Audio service configuration
There are some more options in SoftEncode
-Audio coding mode: mode 4 (L,R,S) and mode 5 (L,C,R,S)
-Bit stream mode: other than Main audio service. Complete main
-Save frames in Intel byte order
I don't need this options.

Bit Stream
-Copyright bit
-Original bit stream
-Audio production information
Default is ok for me.

Preprocessing
-Input filtering->Digital deemphasis
-Input filtering->DC high-pass filter
-Input filtering->Bandwidth low-pass filter
-Input filtering->LFE low-pass filter
-Surround channel processing->90 degree phase shift
-Surround channel processing->3 dB atenuation
All this utilities can be applied to the wav input before the encoder process.
-Dynamic range compression (DRC):
This info must be generated be the encoder and, I think, is the more important difference between free and commercial encoders at this moment.

Conclusions
To improve Aften encoder there are two priorities for me:
-Generate DRC info. I know is not easy, and out of my knowledge, but I think is important.
-Accept 32 bit Int and Float wav's. If we have a more precise source we lose quality converting to 16 bit Int to be accepted by Aften. I can collaborate with this point if needed.

Questions
About ac3 VBR. Is compatible with avi container and DVD authoring programs?

@Kurtnoise. What is the difference between aften.exe and aften_g.exe in your last pack?
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