Valex's AC3 decoder for Winamp  ver 0.2a

Russian version
Download.


    This program is a Winamp input plugin to play .ac3 files. Based on the same decoder library used in AC3Filter. Distributed absolutely for free (FREEWARE). Sorry if my English is bad, but I think it is better to have something than nothing.



Contents



Download.

New versions can be found at site:
http://xvalex.hotbox.ru/programs/in_vac3


in_vac3 v0.2a
http://xvalex.hotbox.ru/download/in_vac3_0_2a.zip
http://xvalex.hotbox.ru/download/in_vac3_0_2a_src.zip

in_vac3 v0.1a

http://xvalex.hotbox.ru/download/in_vac3_0_1a.zip
http://xvalex.hotbox.ru/download/in_vac3_0_1a_src.zip



Install.

    Just unzip and copy in_vac3.dll to Winamp plugin directory. Import preset.reg file (optional).



Uninstall.

    Just delete in_vac3.dll from Winamp plugin directory. Inmport unintsall.reg to clean the registry.



Settings.



* Bitstream information.

    Top left it is bitstream information (BSI):

* Gain levels.

    Buttom middle it is gain level controls.     Master and Gain controls are responsible for global gain level. Master sets desired gain level. If current sound level is too high and overflow occurs then real gain level will decrease. Current gain level shown at Gain control.

* Dynamic range compression.

    By its nature ac3 is a logarithmic format. Samples are stored in form of exponents and mantissas. In terms of bits one sample can be up to 40bits long (only theoretically) or up to 24bits (normal). It provide huge dynamic range (but, as said by great Einstein all good things in this word are relative :-). This means that quiet sound with low level when played on 16-bit sound card will be not audible at all or will have very low absolute level (=> high distortions). To solve this problem it is dynamic range comression. Main idea is to raise level when sound is quiet (and vice versa when loud) before converting to 16-bit form. There are special markers in ac3 stream for current level change. This markers are set by producer at a mastering stage, so it guarantees high quality. DRC level indicates this level. With 'Use DRC' chekbox  you can enabe/disable using DRC. (of course this is only rough problem description).

    DRC Power control adjusts how much DRC level changes sound level. When DRC Power is increased all quiet sounds will be more stressed and loud sound will be more shaded. When decrease DRC Power dynamic range compression will have less influence at output. Zero DRC Power level means that dynamic range compression applied at normal.

* CPU load.

    Indicates CPU load by sound decoding and processing. All sound processing (if exists) before reproduction included here. (it is not working by now)

* Input/output levels.

    Right part - levels indication. Note that levels here are in logarithmic scale. Input levels shows real channels configuration. Often happens that when BSI shows 5.1 in real LFE channel is absent.

* Presets

    Combo box at bottom right allows to load predefined sets of settings (presets):

* Options




Distribution.

    This program distributed under GNU General Public Licence v2, placed in GNU_eng.txt at english language and GNU_rus.txt at russian language. Russain language version is only for information purpose only and english version have priority with all variant reading.

    This application may solely be used for demonstration and educational purposes. Any other use may be prohibited by law in some coutries. The author has no liability regarding this application whatsoever. This application may be distributed freely unless prohibited by law.

    This product distributed in hope it may be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose and compliance with any standarts. I do not guarantee 24-hour (and any) support, bug correction, repair of lost data, I am not responsible for broken hardware and lost working time. I am not responsible for legality of reproducted with this program multimedia production.



Contact author.

    With all questions about this program please, email to this address.  Please, respond about all errors in porgram.



Changelog.

0.2a - 20.11.2002
  * Everything was rewritten :)
  + Configuration dialog added.
  + Settings are saved to registry.

0.1a - 30.10.2002
  * first working alfa


Copyright (c) 2002 by Vigovsky Alexander.
Last updated 20.11.2002