diff options
| -rw-r--r-- | alc/alc.cpp | 9 | ||||
| -rw-r--r-- | alc/alu.cpp | 85 | ||||
| -rw-r--r-- | alc/front_stablizer.h | 11 |
3 files changed, 53 insertions, 52 deletions
diff --git a/alc/alc.cpp b/alc/alc.cpp index c7a24e42..acc99e6e 100644 --- a/alc/alc.cpp +++ b/alc/alc.cpp @@ -2096,13 +2096,10 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const int *attrList) if(GetConfigValueBool(device->DeviceName.c_str(), nullptr, "front-stablizer", 0)) { auto stablizer = std::make_unique<FrontStablizer>(); - /* Initialize band-splitting filters for the front-left and front- - * right channels, with a crossover at 5khz (could be higher). + /* Initialize band-splitting filter for the mid signal, with a + * crossover at 5khz (could be higher). */ - const float scale{5000.0f / static_cast<float>(device->Frequency)}; - - stablizer->LFilter.init(scale); - stablizer->RFilter = stablizer->LFilter; + stablizer->MidFilter.init(5000.0f / static_cast<float>(device->Frequency)); device->Stablizer = std::move(stablizer); /* NOTE: Don't know why this has to be "copied" into a local static diff --git a/alc/alu.cpp b/alc/alu.cpp index bf713eda..40fb12f0 100644 --- a/alc/alu.cpp +++ b/alc/alu.cpp @@ -1830,45 +1830,51 @@ void ApplyStablizer(FrontStablizer *Stablizer, const al::span<FloatBufferLine> B } } - float (&lsplit)[2][BUFFERSIZE] = Stablizer->LSplit; - float (&rsplit)[2][BUFFERSIZE] = Stablizer->RSplit; - const al::span<float> tmpbuf{Stablizer->TempBuf, SamplesToDo+FrontStablizer::DelayLength}; + al::span<float> tmpbuf{Stablizer->TempBuf, SamplesToDo+FrontStablizer::DelayLength}; - /* This applies the band-splitter, preserving phase at the cost of some - * delay. The shorter the delay, the more error seeps into the result. + /* Use the right delay buf for the side signal delay. Combine the delayed + * signal with the incoming signal. */ - auto apply_splitter = [tmpbuf,SamplesToDo](const FloatBufferLine &InBuf, - const al::span<float,FrontStablizer::DelayLength> DelayBuf, BandSplitter &Filter, - float (&splitbuf)[2][BUFFERSIZE]) -> void - { - /* Combine the input and delayed samples into a temp buffer in reverse, - * then copy the final samples into the delay buffer for next time. - * Note that the delay buffer's samples are stored backwards here. - */ - auto tmp_iter = std::reverse_copy(InBuf.cbegin(), InBuf.cbegin()+SamplesToDo, - tmpbuf.begin()); - std::copy(DelayBuf.cbegin(), DelayBuf.cend(), tmp_iter); - std::copy_n(tmpbuf.cbegin(), DelayBuf.size(), DelayBuf.begin()); - - /* Apply an all-pass on the reversed signal, then reverse the samples - * to get the forward signal with a reversed phase shift. - */ - Filter.applyAllpass(tmpbuf); - std::reverse(tmpbuf.begin(), tmpbuf.end()); + auto tmpiter = std::copy_n(std::begin(Stablizer->DelayBuf[ridx]), FrontStablizer::DelayLength, + tmpbuf.begin()); + for(size_t i{0};i < SamplesToDo;++i,++tmpiter) + *tmpiter = Buffer[lidx][i] - Buffer[ridx][i]; + /* Hold on to the beginning for later, and save the end for next time. */ + std::copy_n(tmpbuf.begin(), SamplesToDo, std::begin(Stablizer->Side)); + std::copy_n(tmpbuf.begin()+SamplesToDo, FrontStablizer::DelayLength, + std::begin(Stablizer->DelayBuf[ridx])); + + /* Use the left delay buf for the mid signal delay. Combine the delayed + * signal with the incoming signal. Note that the samples are stored and + * combined in reverse, so the newest samples are at the front and the + * oldest at the back. + */ + tmpiter = tmpbuf.begin() + SamplesToDo; + std::copy_n(std::cbegin(Stablizer->DelayBuf[lidx]), FrontStablizer::DelayLength, tmpiter); + for(size_t i{0};i < SamplesToDo;++i) + *--tmpiter = Buffer[lidx][i] + Buffer[ridx][i]; + /* Save the newest samples for next time. */ + std::copy_n(tmpbuf.cbegin(), FrontStablizer::DelayLength, + std::begin(Stablizer->DelayBuf[lidx])); + + /* Apply an all-pass on the reversed signal, then reverse the samples to + * get the forward signal with a reversed phase shift. The future samples + * are included with the all-pass to reduce the error in the output + * samples (the smaller the delay, the more error is introduced). + */ + Stablizer->MidFilter.applyAllpass(tmpbuf); + tmpbuf = tmpbuf.subspan<FrontStablizer::DelayLength>(); + std::reverse(tmpbuf.begin(), tmpbuf.end()); - /* Now apply the band-splitter, combining its phase shift with the - * reversed phase shift, restoring the original phase on the split - * signal. - */ - Filter.process(tmpbuf.first(SamplesToDo), splitbuf[1], splitbuf[0]); - }; - apply_splitter(Buffer[lidx], Stablizer->DelayBuf[lidx], Stablizer->LFilter, lsplit); - apply_splitter(Buffer[ridx], Stablizer->DelayBuf[ridx], Stablizer->RFilter, rsplit); + /* Now apply the band-splitter, combining its phase shift with the reversed + * phase shift, restoring the original phase on the split signal. + */ + Stablizer->MidFilter.process(tmpbuf, Stablizer->MidHF, Stablizer->MidLF); - /* This pans the separate low- and high-frequency sums between being on the - * center channel and the left/right channels. The low-frequency sum is - * 1/3rd toward center (2/3rds on left/right) and the high-frequency sum is - * 1/4th toward center (3/4ths on left/right). These values can be tweaked. + /* This pans the separate low- and high-frequency signals between being on + * the center channel and the left+right channels. The low-frequency signal + * is panned 1/3rd toward center and the high-frequency signal is panned + * 1/4th toward center. These values can be tweaked. */ const float cos_lf{std::cos(1.0f/3.0f * (al::MathDefs<float>::Pi()*0.5f))}; const float cos_hf{std::cos(1.0f/4.0f * (al::MathDefs<float>::Pi()*0.5f))}; @@ -1876,12 +1882,9 @@ void ApplyStablizer(FrontStablizer *Stablizer, const al::span<FloatBufferLine> B const float sin_hf{std::sin(1.0f/4.0f * (al::MathDefs<float>::Pi()*0.5f))}; for(ALuint i{0};i < SamplesToDo;i++) { - float lfsum{lsplit[0][i] + rsplit[0][i]}; - float hfsum{lsplit[1][i] + rsplit[1][i]}; - float s{lsplit[0][i] + lsplit[1][i] - rsplit[0][i] - rsplit[1][i]}; - - float m{lfsum*cos_lf + hfsum*cos_hf}; - float c{lfsum*sin_lf + hfsum*sin_hf}; + const float m{Stablizer->MidLF[i]*cos_lf + Stablizer->MidHF[i]*cos_hf}; + const float c{Stablizer->MidLF[i]*sin_lf + Stablizer->MidHF[i]*sin_hf}; + const float s{Stablizer->Side[i]}; /* The generated center channel signal adds to the existing signal, * while the modified left and right channels replace. diff --git a/alc/front_stablizer.h b/alc/front_stablizer.h index ad31508a..179a1953 100644 --- a/alc/front_stablizer.h +++ b/alc/front_stablizer.h @@ -10,14 +10,15 @@ struct FrontStablizer { static constexpr size_t DelayLength{256u}; - alignas(16) float DelayBuf[MAX_OUTPUT_CHANNELS][DelayLength]; - - BandSplitter LFilter, RFilter; - alignas(16) float LSplit[2][BUFFERSIZE]; - alignas(16) float RSplit[2][BUFFERSIZE]; + BandSplitter MidFilter; + alignas(16) float MidLF[BUFFERSIZE]; + alignas(16) float MidHF[BUFFERSIZE]; + alignas(16) float Side[BUFFERSIZE]; alignas(16) float TempBuf[BUFFERSIZE + DelayLength]; + alignas(16) float DelayBuf[MAX_OUTPUT_CHANNELS][DelayLength]; + DEF_NEWDEL(FrontStablizer) }; |