audio: WASAPI exclusive resampling, buffer size increase options (#727)

## Link to GitHub Issue or related Pull Request, if one exists n/a ## Description of change Resampler: Implement resampler for exclusive mode streams, as we are seeing more and more devices - not just laptops but onboard audio devices - that only support 48khz and not 44.1khz. Should work with volume boost (gain calculated inside resample) and also downmixer (hands off intermediate scratch buffers). Buffer size increase: By default many of these games request a tiny buffer when in shared mode (TDJ uses 3ms). On some audio setup this results in crackling due to underflow. Add an option to forcibly increase the buffer size. ## Testing With resampler set to 48kHz and buffer set to 20ms I can reliably boot and play IIDX on my display port monitor's speakers; previously this wasn't possible. IIDX is event-driven. Tested SDVX7 as well at 48kHz, which opens timer-driven streams.
2026-08-06 16:40:41 -07:00 · 2026-06-02 01:55:50 -07:00
parent b517ef3182
commit 48033816a8
17 changed files with 967 additions and 128 deletions
@@ -1,8 +1,100 @@
 #pragma once

+#include <algorithm>
+#include <cmath>
+#include <cstdint>
+#include <cstring>
 #include <string>

 #include <windows.h>
 #include <mmreg.h>
+#include <audioclient.h>

 std::string stream_flags_str(DWORD flags);
+
+// log the stream parameters (share mode, flags, buffer duration, periodicity) followed by the wave
+// format, matching the block printed at the top of IAudioClient::Initialize.
+void print_format(AUDCLNT_SHAREMODE share_mode, DWORD stream_flags, REFERENCE_TIME buffer_duration,
+        REFERENCE_TIME periodicity, const WAVEFORMATEX *device_format);
+
+// log the share mode followed by the wave format, for paths that only have a share mode (e.g.
+// IAudioClient::IsFormatSupported).
+void print_format(AUDCLNT_SHAREMODE share_mode, const WAVEFORMATEX *device_format);
+
+// detect IEEE float samples: WAVE_FORMAT_IEEE_FLOAT, or WAVE_FORMAT_EXTENSIBLE whose SubFormat is
+// KSDATAFORMAT_SUBTYPE_IEEE_FLOAT (Data1 == 3; _PCM has Data1 == 1)
+inline bool is_ieee_float(const WAVEFORMATEX *fmt) {
+    return fmt->wFormatTag == WAVE_FORMAT_IEEE_FLOAT
+        || (fmt->wFormatTag == WAVE_FORMAT_EXTENSIBLE
+            && reinterpret_cast<const WAVEFORMATEXTENSIBLE *>(fmt)->SubFormat.Data1 == 0x00000003);
+}
+
+// read one sample at `p` as a normalized float in [-1, 1]
+inline float read_sample(const BYTE *p, int bytes, bool is_float) {
+    if (is_float) {
+        float v;
+        memcpy(&v, p, sizeof(float));
+        return v;
+    }
+    switch (bytes) {
+        case 2: {
+            int16_t v;
+            memcpy(&v, p, sizeof(v));
+            return v * (1.0f / 32768.0f);
+        }
+        case 3: {
+            int32_t v = p[0] | (p[1] << 8) | (p[2] << 16);
+            if (v & 0x800000) {
+                v |= ~0xFFFFFF; // sign extend
+            }
+            return v * (1.0f / 8388608.0f);
+        }
+        case 4: {
+            int32_t v;
+            memcpy(&v, p, sizeof(v));
+            return (float) (v * (1.0 / 2147483648.0));
+        }
+        default:
+            return 0.0f;
+    }
+}
+
+// write the normalized float `value` to the sample at `p`, clamping to the format's range
+inline void write_sample(BYTE *p, int bytes, bool is_float, float value) {
+    if (is_float) {
+        float v = std::clamp(value, -1.0f, 1.0f);
+        memcpy(p, &v, sizeof(v));
+        return;
+    }
+    switch (bytes) {
+        case 2: {
+            int16_t v = (int16_t) std::clamp(
+                (int) std::lround(value * 32768.0f), -32768, 32767);
+            memcpy(p, &v, sizeof(v));
+            break;
+        }
+        case 3: {
+            int32_t v = (int32_t) std::clamp<int64_t>(
+                std::llround((double) value * 8388608.0), -8388608, 8388607);
+            p[0] = v & 0xFF;
+            p[1] = (v >> 8) & 0xFF;
+            p[2] = (v >> 16) & 0xFF;
+            break;
+        }
+        case 4: {
+            int32_t v = (int32_t) std::clamp<int64_t>(
+                std::llround((double) value * 2147483648.0), INT32_MIN, INT32_MAX);
+            memcpy(p, &v, sizeof(v));
+            break;
+        }
+        default:
+            break;
+    }
+}
+
+// initialize the real audio client, recovering from AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED by asking the
+// device for the next aligned buffer size and re-initializing with a matching duration. log_group
+// names the subsystem in the retry log line.
+HRESULT initialize_with_alignment_retry(IAudioClient *client, const char *log_group,
+        AUDCLNT_SHAREMODE share_mode, DWORD stream_flags, REFERENCE_TIME buffer_duration,
+        REFERENCE_TIME periodicity, const WAVEFORMATEX *device_format, LPCGUID session_guid);