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fix range used for native volume in Set/GetVolume() and simplify the code a bit

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@49026 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2007-10-03 22:35:44 +00:00
parent a19e936e75
commit 6e0e886278
1 changed files with 11 additions and 28 deletions
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39
src/msw/mediactrl_am.cpp
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@@ -1956,12 +1956,12 @@ wxLongLong wxAMMediaBackend::GetPosition()
}
//---------------------------------------------------------------------------
// wxAMMediaBackend::GetVolume
// wxAMMediaBackend::GetVolume and SetVolume()
//
// Gets the volume through the IActiveMovie interface -
// value ranges from 0 (MAX volume) to -10000 (minimum volume).
// -100 per decibel (Logorithmic in 0.01db per step).
// Notice that for the IActiveMovie interface value ranges from 0 (MAX volume)
// to -10000 (minimum volume) and the scale is logarithmic in 0.01db per step.
//---------------------------------------------------------------------------
double wxAMMediaBackend::GetVolume()
{
long lVolume;
@@ -1972,37 +1972,20 @@ double wxAMMediaBackend::GetVolume()
return 0.0;
}
// Volume conversion from Greg Hazel
double dVolume = (double)lVolume / 125;
double dVolume = lVolume / 2000.; // volume is now in [-5..0] range
dVolume = pow(10.0, dVolume); // [10^-5, 1]
dVolume -= 0.00001; // [0, 1-10^-5]
dVolume /= 1 - 0.00001; // [0, 1]
// convert to 0 to 1
dVolume = pow(10.0, dVolume/20.0);
// handle -INF
dVolume *= 1 + pow(10.0, -5.0);
dVolume -= pow(10.0, -5.0);
return dVolume;
}
//---------------------------------------------------------------------------
// wxAMMediaBackend::SetVolume
//
// Sets the volume through the IActiveMovie interface -
// value ranges from 0 (MAX volume) to -10000 (minimum volume).
// -100 per decibel (Logorithmic in 0.01db per step).
//---------------------------------------------------------------------------
bool wxAMMediaBackend::SetVolume(double dVolume)
{
// Volume conversion from Greg Hazel
long lVolume;
// handle -INF
dVolume *= 1 - pow(10.0, -5.0);
dVolume += pow(10.0, -5.0);
// convert to -100db to 0db
dVolume = 20 * log10(dVolume);
// scale to -10000 to 0
lVolume = (long)(125 * dVolume);
// inverse the transformation above
long lVolume = 2000*log10(dVolume + (1 - dVolume)*0.00001);
HRESULT hr = GetAM()->put_Volume( lVolume );
HRESULT hr = GetAM()->put_Volume(lVolume);
if(FAILED(hr))
{
wxAMLOG(hr);