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fix(audio): set the bits-per-sample of Steam Streaming Speakers to 16-bit when the default audio device is 16-bit #3704

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Merged
ReenigneArcher merged 1 commit into from
Apr 19, 2025
Merged

fix(audio): set the bits-per-sample of Steam Streaming Speakers to 16-bit when the default audio device is 16-bit #3704

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39 changes: 37 additions & 2 deletions src/platform/windows/audio.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -117,15 +117,26 @@ namespace {

using virtual_sink_waveformats_t = std::vector<WAVEFORMATEXTENSIBLE>;

/**
* @brief List of supported waveformats for an N-channel virtual audio device
* @tparam channel_count Number of virtual audio channels
* @returns std::vector<WAVEFORMATEXTENSIBLE>
* @note The list of virtual formats returned are sorted in preference order and the first valid
* format will be used. All bits-per-sample options are listed because we try to match
* this to the default audio device. See also: set_format() below.
*/
template<WORD channel_count>
virtual_sink_waveformats_t create_virtual_sink_waveformats() {
if constexpr (channel_count == 2) {
auto channel_mask = waveformat_mask_stereo;
// only choose 24 or 16-bit formats to avoid clobbering existing Dolby/DTS spatial audio settings
// The 32-bit formats are a lower priority for stereo because using one will disable Dolby/DTS
// spatial audio mode if the user enabled it on the Steam speaker.
return {
create_waveformat(sample_format_e::s24in32, channel_count, channel_mask),
create_waveformat(sample_format_e::s24, channel_count, channel_mask),
create_waveformat(sample_format_e::s16, channel_count, channel_mask),
create_waveformat(sample_format_e::f32, channel_count, channel_mask),
create_waveformat(sample_format_e::s32, channel_count, channel_mask),
};
} else if (channel_count == 6) {
auto channel_mask1 = waveformat_mask_surround51_with_backspeakers;
Expand Down Expand Up @@ -298,6 +309,10 @@ namespace platf::audio {
auto waveformatext_pointer = reinterpret_cast<const WAVEFORMATEXTENSIBLE *>(mixer_waveformat.get());
capture_waveformat.dwChannelMask = waveformatext_pointer->dwChannelMask;
}

BOOST_LOG(info) << "Audio mixer format is "sv << mixer_waveformat->wBitsPerSample << "-bit, "sv
<< mixer_waveformat->nSamplesPerSec << " Hz, "sv
<< ((mixer_waveformat->nSamplesPerSec != 48000) ? "will be resampled to 48000 by Windows"sv : "no resampling needed"sv);
}

status = audio_client->Initialize(
Expand All @@ -315,7 +330,7 @@ namespace platf::audio {
return nullptr;
}

BOOST_LOG(info) << "Audio capture format is " << logging::bracket(waveformat_to_pretty_string(capture_waveformat));
BOOST_LOG(info) << "Audio capture format is "sv << logging::bracket(waveformat_to_pretty_string(capture_waveformat));

return audio_client;
}
Expand Down Expand Up @@ -793,6 +808,22 @@ namespace platf::audio {
}
}

// When switching to a Steam virtual speaker device, try to retain the bit depth of the
// default audio device. Switching from a 16-bit device to a 24-bit one has been known to
// cause glitches for some users.
int wanted_bits_per_sample = 32;
auto current_default_dev = default_device(device_enum);
if (current_default_dev) {
audio::prop_t prop;
prop_var_t current_device_format;

if (SUCCEEDED(current_default_dev->OpenPropertyStore(STGM_READ, &prop)) && SUCCEEDED(prop->GetValue(PKEY_AudioEngine_DeviceFormat, &current_device_format.prop))) {
auto *format = (WAVEFORMATEXTENSIBLE *) current_device_format.prop.blob.pBlobData;
wanted_bits_per_sample = format->Samples.wValidBitsPerSample;
BOOST_LOG(info) << "Virtual audio device will use "sv << wanted_bits_per_sample << "-bit to match default device"sv;
}
}

auto &device_id = virtual_sink_info->first;
auto &waveformats = virtual_sink_info->second.get().virtual_sink_waveformats;
for (const auto &waveformat : waveformats) {
Expand All @@ -802,6 +833,10 @@ namespace platf::audio {
auto waveformat_copy = waveformat;
auto waveformat_copy_pointer = reinterpret_cast<WAVEFORMATEX *>(&waveformat_copy);

if (wanted_bits_per_sample != waveformat.Samples.wValidBitsPerSample) {
continue;
}

WAVEFORMATEXTENSIBLE p {};
if (SUCCEEDED(policy->SetDeviceFormat(device_id_copy.c_str(), waveformat_copy_pointer, (WAVEFORMATEX *) &p))) {
BOOST_LOG(info) << "Changed virtual audio sink format to " << logging::bracket(waveformat_to_pretty_string(waveformat));
Expand Down