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decoder. But with AC3Filter installed NVDVD tries to load AC3Filter
instead and cannot proceed. To revert high priority choose <b>'Prefer
AC3Filter</b>'. <br>
This option requires relogon in W2k/XP and system
restart in W98.<br>
<br>
<b>* Default audio renderer</b><br>
<br>
Sound card may work in two modes: DirectSound and
WaveOut. If it is some problems when using filter (for example if SPDIF
does not work) it is possible that mode switch may help. Some media
players (BSP) have corresponding settings but most of others use system
default settings. Choose <b>'Use DirectSound'</b> to make DirectSound to
be default interface; choose <b>'Use WaveOut</b>' to make WaveOut to be
default interface.<br>
This option requires relogon in W2k/XP and system
restart in W98.<br>
<br>
<b> * Audio/Video sync.</b><br>
<br>
Sometimes it may happen that audio and video are not
in sync. Mostly it happens because of incorrect mixing, but it may be
also some hardware reasons. This option is designed to fix <b>hardware</b>
issues. You can use it to watch movies that was incorrectly mixed but do
not forget to change it back after! This option specifies time shift
between audio and video. If audio is played <u><i>before</i></u> video
you need to <u><i>increase</i></u> this value. If audio is played <u><i>after</i></u>
video you need to <u><i>decrease</i></u> this value. Note, that this
option allows to fix only constant time shift.<br>
This option have immediate effect. When you change
it picture may freeze for several seconds to resync, it is normal.<br>
<br>
<b>* System options</b><br>
<br>
<b>Auto load movie configuration files</b> - If this
option is enabled filter will try to find and load configuration file
with the same name as media file.<br>
<br>
<b>Generate timestamps</b> - This option may affect
video stuttering. Try to switch it if you see video stuttering,
non-fluent video. It is most common case when this option is enabled. In
this case filter will calculate time for each ac3 frame decoded. But
this time may differ from time got from media file (in fact times are
always different for .avi files) and this may produce video stuttering
on some systems. It does not mean that filter calculate timestamps
incorrectly or timestamps in media file are incorrect, but it is a
general problem of .avi files with frame-based interleaving. Partially
this porblem may be solved with '<b>Jitter correction</b>' option.<br>
If this option is disabled filter will use only
timestamps from media file. This may solve the problem with different
timestamps. But in this case some decoded ac3 frames will have no
timestamps at all. Some players/drivers cannot handle this situation
correctly and may produce stuttering/frozen frames or other unpleasant
effects.<br>
<br>
<b>Jitter Correction</b> - works only when '<b>Generate
timestamps</b>' is enabled. Decrease the stutterring due to the
difference between calculated and received timestamps. '<b>Current jitter</b>'
shows the current amplitude of deviations.<br>
<br>
<b>Use WAVEFORMATEXTENSIBLE</b> - generally for
multichannel modes it is WAVEFORMATEXTENSIBLE structure used (described
at <a href="http://www.microsoft.com/hwdev/tech/audio/multichaud.asp">http://www.microsoft.com/hwdev/tech/audio/multichaud.asp</a>).
Some old drivers cannot work with it (opposite, some new drivers can
work only with this structure in multichannel).<br>
<br>
<h3><a name="w98"></a>Windows 98</h3>
By deafult Windows98 does not support multichannel
and spdif modes.<br>
First you need to install microsoft patch for
WaveOut:<br>
<b>server1:</b> <a href="ftp://ftp.asus.com.tw/pub/ASUS/beta/mb/driver/269601USA8.EXE">ftp://ftp.as
us.com.tw/pub/ASUS/beta/mb/driver/269601USA8.EXE</a><br>
<b>server2:</b> <a href="ftp://download.intel.com/design/motherbd/bt2/269601USA8.EXE">ftp://downloa
d.intel.com/design/motherbd/bt2/269601USA8.EXE</a><br>
<b> server3:</b> <a href="http://ac3filter.sourceforge.net/download/269601USA8.EXE">http://ac3filter
.sourceforge.net/download/269601USA8.EXE</a><br>
<br>
This patch is described at <a href="http://www.microsoft.com/hwdev/tech/audio/Non-%0D%0APCM.asp">http://www.microsoft.com/hwdev/tech/audio/Non-PCM.asp</a>.<br>
Second is set WaveOut Device as default device for
audio output. <br>
After it in most players multichannel modes and
spdif output may work.<br>
<br>
<h3><a name="nt4"></a>WinNT4</h3>
ServicePack6 is required.<br>
<br>
<h3><a name="w2k"></a>Win2K</h3>
ServicePack2 is highly recommended.<br>
<br>
<h3><a name="vortex"></a>Vortex</h3>
If muiltichannel modes do not work try to uncheck '<b>Use
WAVEFORMATEXTENSIBLE</b>' option at 'System' filter's property page.<br>
<br>
<br>
<hr width="100%" size="2">
<h2><a name="player_settings"></a>Players setup.</h2>
Most players do not require any setup and filter is
used automatically.<br>
<br>
<h3><a name="BSPlayer"></a>BSPlayer</h3>
In player settings (<b>Options->Preferences</b>)
set: <br>
<ul>
<li>General->Don't load ac3 settings: checked </li>
<li>Audio->For AC3 decoding use: '--'</li>
</ul>
<h3><a name="ZoomPlayer"></a>ZoomPlayer</h3>
To play AVI files player does not require any
settings. But this player can be used as DVD player (instead of widely
used PowerDVD or WinDVD). To play DVDs with using of AC3Filter next
files are required:<br>
<br>
<a href="http://ac3filter.sourceforge.net/download/zoom/AC3Filter-CyberLink-DirectSound.dvdgraph">http://ac3filter.sourceforge.net/download/zoom/AC3Filter-CyberLink-DirectSound.dvdgraph</a><br>
<a href="http://ac3filter.sourceforge.net/download/zoom/AC3Filter-InterVideo-DirectSound.dvdgraph">http://ac3filter.sourceforge.net/download/zoom/AC3Filter-InterVideo-DirectSound.dvdgraph</a><br>
<a href="http://ac3filter.sourceforge.net/download/zoom/AC3Filter-CyberLink-Waveout.dvdgraph">http://ac3filter.sourceforge.net/download/zoom/AC3Filter-CyberLink-Waveout.dvdgraph</a><br>
<a href="http://ac3filter.sourceforge.net/download/zoom/AC3Filter-InterVideo-Waveout.dvdgraph">http://ac3filter.sourceforge.net/download/zoom/AC3Filter-InterVideo-Waveout.dvdgraph</a><br>
<br>
Place this files to ...\ZoomPlayer\DVDGraph folder.
In player settings <b>Player Options->DVD->DVD Setup</b> choose
required option (depends on installed video decoder).<br>
<br>
<br>
<hr width="100%" size="2">
<h2><b><a name="usage"></a>Filter configuration.</b><br>
</h2>
<big><i><br>
First it is two main rules of tuning:<br>
1. If you do not understand what some option does do
not touch it.<br>
2. If you did not follow the first rule and broke
anything and do not know how to fix it just load 'standart' preset.<br>
:)))<br>
</i></big><br>
Filter can be configured with several ways. Best is
if player allow to call filter properties (WMP 6.4, BSP, Sasami, etc,
not in WMP 7, 8, 9!). For example in WMP 6.4 filter list can be
accessed <b>File- >Properties->Advanced</b>:<br>
<br>
<div align="center"><img src="pic/filters.gif" alt="" width="425" height="435"> <br>
</div>
<br>
<br>
If player does not allow to reach filter settings it
is possible to configure it from Start menu with '<b>AC3Filter Config</b>'
icon or Control Panel icon. But this method do not show current
activity and do not affect it! I.e. levels will not change, bitstream
information will be filled with zeros etc. Moreover all players should
be closed <i><small>(because when player is closing filter saves its
configuration to registry, so now configured values may be overwrited
with old values that was read at player startup). </small></i>So it is
highly recommended to configure filter from within player that allow
access to filter properties (almost any of widespreaded: BSPlayer,
Sasami, ZoomPlayer, LightAlloy, etc). In last case you can hear how any
change in settings affects sound. WMP v7, 8, 9 are not recommended.<br>
<br>
<h3><a name="main_settings"></a>Main settings</h3>
Here is <b>Main</b> property page (levels and
bitstream info are only shown when property page is called from player):<br>
<br>
<div align="center"><img src="pic/main.gif" title="" alt="" width="628" height="427"> <br>
</div>
<br>
<b>* Bitstream information</b>.<br>
<br>
Top left it is bitstream information (BSI):<br>
<ul>
<li><b>裩annels</b> - channels configuration in form
front_channels/surround_channels + LFE (Low frequency effects channel)
presence flag. In this example it is 3 front, 2 surround and LFE
channels, i.e. 5.1 configuration.</li>
<li><b>Sample rate</b> [Hz]</li>
<li><b>Bitrate</b> [bps]</li>
<li><b>Freq</b> (coupl/high) - [kHz], coupling frequency and high
freuency. In ac3 some channels (in most cases all channels) are
grouped in one coupling channel beginning from some frequency -
coupling frequency and stored in the bitstream in that form. So
channels are really independent only in some frequency band - up
to coupling frequency. High frequency is a maximum frequency coded, so
it defines total frequency bandwidth.</li>
<li><b>Frames/errors</b> - total number of decoded frames and
number of errors when decoding.</li>
</ul>
<h4><b>* Output.</b></h4>
Here you can change output configuration. It define
the real speaker configuration to wich ac3 channels will be mixed.
Shown in form front_channels/surround_channels + subwoofer presence
flag (SW). For some configurations common names are given. What is the
difference between LFE and subwoofer read in <a href="#lfe">What is LFE?</a>
section.<br>
<br>
'<b>Dolby Surround/ProLogic</b>' modes mean that
that all channels presented in ac3 stream will be mixed into two
channels so Dolby Surround/Pro Logic decoder can extract surround
channel. '<b>Dolby ProLogic II</b>' mode is similar to DPL but for DPL
II decoder. DPLII support is only experimental because of lack of
reliable information.<br>
<br>
'<b>SPDIF</b>' mode means that ac3 stream will be
routed to digital out of sound card directly and without any
modification. So no one of other settings will work if this checkbox is
checked.<br>
<br>
'<b>Sample format</b>' combo box sets output sample
format. There are PCM 16 bit, 24 and 32 bit and PCM Float formats are
now supported. On some sound cards some formats may not work so use this
option with care.<br>
<br>
<b>* Gain levels.</b> <br>
<br>
Here you can control gain levels.
<ul>
<li><b>Master</b> - desired gain level.</li>
<li><b>Gain</b> - shows current gain level.</li>
<li><b>LFE</b> - LFE channel gain level</li>
<li><b>Voice</b> - center channel gain level (dialogue channel)</li>
<li><b>Surround</b> - surround channel(s) gain level..</li>
<li><b>BSI Lock</b> checkboxes - lock channel gain level at values
given by standard. You cannot change Voice, LFE and surround gains when
it is enables.</li>
<li><b>Normalize</b> - one-pass sound normalize. (look at <a href="#mixer">Mixer settings</a>)</li>
</ul>
<b>Master</b> and <b>Gain</b> controls are
responsible for global gain level. <b>Master</b> sets desired gain
level. If current sound level is too high and overflow occurs then real
gain level will be decreased. Current gain level shown at <b>Gain</b>
control.<br>
<br>
<h4><b>* Dynamic range compression.</b></h4>
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 provides 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. <b>DRC level</b>
indicates this level. With <b>Use DRC</b> chekbox you can enabe/disable
using DRC. <i>(of course this is only rough problem description).</i><br>
<br>
<b>DRC Power</b> control adjusts how much <b>DRC
level</b> changes sound level. When <b>DRC Power</b> is increased all
quiet sounds will be more stressed and loud sound will be more shaded.
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