diff --git a/src/audio.c b/src/audio.c
index 6fe7726f63..0299246ac7 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -344,7 +344,185 @@ int map_sound_info(const char* filename)
 */
 void sub_401000(UINT uTimerID, UINT uMsg, DWORD_PTR dwUser, DWORD_PTR dw1, DWORD_PTR dw2, int channel)
 {
-	RCT2_CALLFUNC_6(0x00401000, void, UINT, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR, int, uTimerID, uMsg, dwUser, dw1, dw2, channel);
+	//RCT2_CALLFUNC_6(0x00401000, void, UINT, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR, int, uTimerID, uMsg, dwUser, dw1, dw2, channel);
+	rct_sound_unknown* unknown = &RCT2_ADDRESS(0x014262E0, rct_sound_unknown)[channel];
+	DWORD status;
+	DWORD dwCurrentPlayCursor;
+	DWORD dwCurrentWriteCursor;
+	int var1;
+	int var2;
+	int bufferlost = 0;
+	char* buf1;
+	int buf1size;
+	char* buf2;
+	int buf2size;
+	unknown->dsbuffer->lpVtbl->GetStatus(unknown->dsbuffer, &status);
+	if (status & DSBSTATUS_BUFFERLOST) {
+		if (FAILED(unknown->dsbuffer->lpVtbl->Restore(unknown->dsbuffer))) {
+			return;
+		}
+		unknown->playpos = 0;
+		bufferlost = 1;
+	}
+	unknown->dsbuffer->lpVtbl->GetCurrentPosition(unknown->dsbuffer, &dwCurrentPlayCursor, &dwCurrentWriteCursor);
+	if (dwCurrentPlayCursor != unknown->playpos || bufferlost) {
+		if (unknown->var_168 && !unknown->var_15C) {
+			if (!unknown->var_160) {
+				unknown->var_160 = 1;
+				if (!unknown->var_4) {
+					LPDIRECTSOUNDBUFFER dsbuffer = RCT2_ADDRESS(RCT2_ADDRESS_DSOUND_BUFFERS, LPDIRECTSOUNDBUFFER)[channel];
+					unknown->var_0 = 0;
+					if (dsbuffer) {
+						dsbuffer->lpVtbl->Stop(dsbuffer);
+						dsbuffer->lpVtbl->Release(dsbuffer);
+						RCT2_ADDRESS(RCT2_ADDRESS_DSOUND_BUFFERS, LPDIRECTSOUNDBUFFER)[channel] = 0;
+					}
+					if (unknown->var_120) {
+						sound_channel_free(&unknown->var_120, &unknown->var_11C);
+					}
+				}
+			}
+			return;
+		}
+		if (dwCurrentPlayCursor >= unknown->playpos) {
+			var1 = dwCurrentPlayCursor - unknown->playpos;
+		} else {
+			var1 = dwCurrentPlayCursor + unknown->var_150 - unknown->playpos;
+		}
+		if (bufferlost) {
+			var2 = 2 * unknown->var_150 / 6;
+		} else {
+			var2 = var1;
+		}
+		unknown->var_158 += var1;
+		if (unknown->var_168) {
+			int var3 = unknown->var_15C;
+			int* var4 = &unknown->var_15C;
+			if (var3) {
+				if (var1 <= var3) {
+					*var4 = var3 - var1;
+				} else {
+					*var4 = 0;
+				}
+				if (SUCCEEDED(unknown->dsbuffer->lpVtbl->Lock(unknown->dsbuffer, unknown->playpos, var2, &buf1, &buf1size, &buf2, &buf2size, 0))) {
+					char var5 = -(((char*)unknown->var_11C + 14) != (char *)8);
+					var5 &= 0x80;
+					memset(buf1, var5 + 128, buf1size);
+					if (buf2 && buf2size) {
+						char var5 = -(((char*)unknown->var_11C + 14) != (char *)8);
+						var5 &= 0x80;
+						memset(buf2, var5 + 128, buf2size);
+					}
+					unknown->dsbuffer->lpVtbl->Unlock(unknown->dsbuffer, buf1, buf1size, buf2, buf2size);
+					unknown->playpos += var2;
+					if( unknown->playpos >= unknown->var_150) {
+						unknown->playpos = unknown->playpos - unknown->var_150;
+					}
+					return;
+				}
+				// TimeFunc() could not lock DirectSoundBuffer
+				return;
+			}
+		}
+		if (FAILED(unknown->dsbuffer->lpVtbl->Lock(unknown->dsbuffer, unknown->playpos, var2, &buf1, &buf1size, &buf2, &buf2size, 0))) {
+			// TimeFunc() could not lock DirectSoundBuffer
+			return;
+		}
+		if (buf1size) {
+			if (unknown->var_160) {
+				int var5 = -(((char*)unknown->var_11C + 14) != (char *)8);
+				var5 &= 0x80;
+				memset(buf1, var5 + 128, buf1size);
+				goto label49;
+			}
+		}
+		int var7;
+		RCT2_CALLFUNC_5(0x00405383, int, HMMIO, int, char*, int*, int*, unknown->var_120, buf1size, buf1, &unknown->var_124, &var7);
+		if (var7 < buf1size) {
+			if (!unknown->var_164) {
+				int s = *(char*)((char*)unknown->var_11C + 14);
+				int t = buf1size - var7;
+				int v;
+				if (s == 8) {
+					v = 128;
+				} else {
+					if (s != 16) {
+						goto label42;
+					}
+					v = 0;
+				}
+				memset(&buf1[var7], v, t);
+			label42:
+				unknown->var_168 = 1;
+				if (dwCurrentPlayCursor <= unknown->playpos) {
+					unknown->var_15C = unknown->playpos - dwCurrentPlayCursor;
+				} else {
+					unknown->var_15C = unknown->playpos + unknown->var_150 - dwCurrentPlayCursor;
+				}
+				goto label49;
+			}
+			char* v21 = buf1;
+			int v38 = buf1size;
+			do {
+				v38 -= var7;
+				v21 += var7;
+				RCT2_CALLFUNC_1(0x0040153B, int, int, channel);
+				RCT2_CALLFUNC_5(0x00405383, int, HMMIO, int, char*, int*, int*, unknown->var_120, v38, v21, &unknown->var_124, &var7);
+			} while(var7 < v38);
+		}
+	label49:
+		if (buf2size == 0 || unknown->var_160 != 0) {
+			if(buf2 != 0 && buf2size != 0 && unknown->var_160 != 0) {
+				int var5 = -(*(char*)((char*)unknown->var_11C + 14) != 8);
+				var5 &= 0x80;
+				memset(buf2, var5 + 128, buf2size);
+			}
+			goto label68;
+		}
+		RCT2_CALLFUNC_5(0x00405383, int, HMMIO, int, char*, int*, int*, unknown->var_120, buf2size, buf2, &unknown->var_124, &var7);
+		if (var7 >= buf2size) {
+		label68:
+			unknown->dsbuffer->lpVtbl->Unlock(unknown->dsbuffer, buf1, buf1size, buf2, buf2size);
+			unknown->playpos += var2;
+			if( unknown->playpos >= unknown->var_150 ) {
+				unknown->playpos -= unknown->var_150;
+			}
+			if (bufferlost != 0) {
+				unknown->dsbuffer->lpVtbl->Play(unknown->dsbuffer, 0, 0, DSBPLAY_LOOPING);
+			}
+			return;
+		}
+		if (unknown->var_164 != 0) {
+			char* v26 = buf2;
+			int v27 = buf2size;
+			do {
+				v26 += var7;
+				v27 -= var7;
+				RCT2_CALLFUNC_1(0x0040153B, int, int, channel);
+				RCT2_CALLFUNC_5(0x00405383, int, HMMIO, int, char*, int*, int*, unknown->var_120, v27, v26, &unknown->var_124, &var7);
+			} while(var7 < v27);
+			goto label68;
+		}
+		int s = buf2size - var7;
+		int v;
+		if (unknown->var_11C == (HGLOBAL)8) {
+			v = 128;
+		} else {
+			if (unknown->var_11C != (HGLOBAL)16) {
+				goto label58;
+			}
+			v = 0;
+		}
+		memset(&buf2[var7], v, s);
+	label58:
+		unknown->var_168 = 1;
+		if (dwCurrentPlayCursor <= unknown->playpos) {
+			unknown->var_15C = unknown->playpos - dwCurrentPlayCursor;
+		} else {
+			unknown->var_15C = unknown->playpos + unknown->var_150 - dwCurrentPlayCursor;
+		}
+		goto label68;
+	}
 }
 
 /**
diff --git a/src/audio.h b/src/audio.h
index 85aba58db8..b630ba92ce 100644
--- a/src/audio.h
+++ b/src/audio.h
@@ -100,6 +100,101 @@ typedef struct {
 	rct_sound sound;
 } rct_other_sound;
 
+typedef struct {
+	uint32 var_0;
+	uint32 var_4;
+	uint32 var_8;
+	uint16 var_C;
+	uint16 var_E;
+	uint32 var_10;
+	uint32 var_14;
+	uint32 var_18;
+	uint32 var_1C;
+	uint32 var_20;
+	uint32 var_24;
+	uint32 var_28;
+	uint32 var_2C;
+	uint32 var_30;
+	uint32 var_34;
+	uint32 var_38;
+	uint32 var_3C;
+	uint32 var_40;
+	uint32 var_44;
+	uint32 var_48;
+	uint32 var_4C;
+	uint32 var_50;
+	uint32 var_54;
+	uint32 var_58;
+	uint32 var_5C;
+	uint32 var_60;
+	uint32 var_64;
+	uint32 var_68;
+	uint32 var_6C;
+	uint32 var_70;
+	uint32 var_74;
+	uint32 var_78;
+	uint32 var_7C;
+	uint32 var_80;
+	uint32 var_84;
+	uint32 var_88;
+	uint32 var_8C;
+	uint32 var_90;
+	uint32 var_94;
+	uint32 var_98;
+	uint32 var_9C;
+	uint32 var_A0;
+	uint32 var_A4;
+	uint32 var_A8;
+	uint32 var_AC;
+	uint32 var_B0;
+	uint32 var_B4;
+	uint32 var_B8;
+	uint32 var_BC;
+	uint32 var_C0;
+	uint32 var_C4;
+	uint32 var_C8;
+	uint32 var_CC;
+	uint32 var_D0;
+	uint32 var_D4;
+	uint32 var_D8;
+	uint32 var_DC;
+	uint32 var_E0;
+	uint32 var_E4;
+	uint32 var_E8;
+	uint32 var_EC;
+	uint32 var_F0;
+	uint32 var_F4;
+	uint32 var_F8;
+	uint32 var_FC;
+	uint32 var_100;
+	uint32 var_104;
+	uint32 var_108;
+	uint32 var_10C;
+	uint32 var_110;
+	uint32 var_114;
+	uint32 var_118;
+	HGLOBAL var_11C;
+	HMMIO var_120;
+	uint32 var_124;
+	uint32 var_128;
+	uint32 var_12C;
+	uint32 var_130;
+	uint32 var_134;
+	uint32 var_138;
+	uint32 var_13C;
+	uint32 var_140;
+	uint32 var_144;
+	uint32 var_148;
+	LPDIRECTSOUNDBUFFER dsbuffer;	// 0x14C
+	uint32 var_150;
+	uint32 playpos;					// 0x154
+	uint32 var_158;
+	uint32 var_15C;
+	uint32 var_160;
+	uint32 var_164;
+	uint32 var_168;
+} rct_sound_unknown;
+
 int get_dsound_devices();
 int sound_prepare(int sound_id, rct_sound *sound, int channels, int software);
 int sound_play_panned(int sound_id, int x);
@@ -112,6 +207,7 @@ int sound_channel_play(int channel, int a2, int volume, int pan, int frequency);
 int sound_channel_set_frequency(int channel, int frequency);
 int sound_channel_set_pan(int channel, int pan);
 int sound_channel_set_volume(int channel, int volume);
+void sound_channel_free(HMMIO* hmmio, HGLOBAL* hmem);
 int sound_stop(rct_sound *sound);
 int sound_stop_all();
 int unmap_file(LPCVOID base);