diff --git a/dlls/msacm32/tests/msacm.c b/dlls/msacm32/tests/msacm.c
index 747c5fe634d..e897fc95fca 100644
--- a/dlls/msacm32/tests/msacm.c
+++ b/dlls/msacm32/tests/msacm.c
@@ -594,8 +594,116 @@ static void test_prepareheader(void)
     ok(mr == MMSYSERR_NOERROR, "close failed: 0x%x\n", mr);
 }
 
+static void test_acmFormatSuggest(void)
+{
+    WAVEFORMATEX src, dst;
+    DWORD suggest;
+    MMRESULT rc;
+
+    /* Test a valid PCM format */
+    src.wFormatTag = WAVE_FORMAT_PCM;
+    src.nChannels = 1;
+    src.nSamplesPerSec = 8000;
+    src.nAvgBytesPerSec = 16000;
+    src.nBlockAlign = 2;
+    src.wBitsPerSample = 16;
+    src.cbSize = 0;
+    suggest = 0;
+    memset(&dst, 0, sizeof(dst));
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_NOERROR, "failed with error 0x%x\n", rc);
+todo_wine
+    ok(src.wFormatTag == dst.wFormatTag, "expected %d, got %d\n", src.wFormatTag, dst.wFormatTag);
+    ok(src.nChannels == dst.nChannels, "expected %d, got %d\n", src.nChannels, dst.nChannels);
+    ok(src.nSamplesPerSec == dst.nSamplesPerSec, "expected %d, got %d\n", src.nSamplesPerSec, dst.nSamplesPerSec);
+todo_wine
+    ok(src.nAvgBytesPerSec == dst.nAvgBytesPerSec, "expected %d, got %d\n", src.nAvgBytesPerSec, dst.nAvgBytesPerSec);
+todo_wine
+    ok(src.nBlockAlign == dst.nBlockAlign, "expected %d, got %d\n", src.nBlockAlign, dst.nBlockAlign);
+todo_wine
+    ok(src.wBitsPerSample == dst.wBitsPerSample, "expected %d, got %d\n", src.wBitsPerSample, dst.wBitsPerSample);
+
+    /* All parameters from destination are valid */
+    suggest = ACM_FORMATSUGGESTF_NCHANNELS
+            | ACM_FORMATSUGGESTF_NSAMPLESPERSEC
+            | ACM_FORMATSUGGESTF_WBITSPERSAMPLE
+            | ACM_FORMATSUGGESTF_WFORMATTAG;
+    dst = src;
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_NOERROR, "failed with error 0x%x\n", rc);
+    ok(src.wFormatTag == dst.wFormatTag, "expected %d, got %d\n", src.wFormatTag, dst.wFormatTag);
+    ok(src.nChannels == dst.nChannels, "expected %d, got %d\n", src.nChannels, dst.nChannels);
+    ok(src.nSamplesPerSec == dst.nSamplesPerSec, "expected %d, got %d\n", src.nSamplesPerSec, dst.nSamplesPerSec);
+    ok(src.nAvgBytesPerSec == dst.nAvgBytesPerSec, "expected %d, got %d\n", src.nAvgBytesPerSec, dst.nAvgBytesPerSec);
+    ok(src.nBlockAlign == dst.nBlockAlign, "expected %d, got %d\n", src.nBlockAlign, dst.nBlockAlign);
+    ok(src.wBitsPerSample == dst.wBitsPerSample, "expected %d, got %d\n", src.wBitsPerSample, dst.wBitsPerSample);
+
+    /* Test for WAVE_FORMAT_MSRT24 used in Monster Truck Madness 2 */
+    src.wFormatTag = WAVE_FORMAT_MSRT24;
+    src.nChannels = 1;
+    src.nSamplesPerSec = 8000;
+    src.nAvgBytesPerSec = 16000;
+    src.nBlockAlign = 2;
+    src.wBitsPerSample = 16;
+    src.cbSize = 0;
+    dst = src;
+    suggest = ACM_FORMATSUGGESTF_NCHANNELS
+            | ACM_FORMATSUGGESTF_NSAMPLESPERSEC
+            | ACM_FORMATSUGGESTF_WBITSPERSAMPLE
+            | ACM_FORMATSUGGESTF_WFORMATTAG;
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst), suggest);
+todo_wine
+    ok(rc == ACMERR_NOTPOSSIBLE, "failed with error 0x%x\n", rc);
+    memset(&dst, 0, sizeof(dst));
+    suggest = 0;
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst), suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+
+    /* Invalid struct size */
+    src.wFormatTag = WAVE_FORMAT_PCM;
+    rc = acmFormatSuggest(NULL, &src, &dst, 0, suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) / 2, suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    /* cbSize is the last parameter and not required for PCM */
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) - 1, suggest);
+    ok(rc == MMSYSERR_NOERROR, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) - sizeof(dst.cbSize), suggest);
+    ok(rc == MMSYSERR_NOERROR, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) - sizeof(dst.cbSize) - 1, suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    /* cbSize is required for others */
+    src.wFormatTag = WAVE_FORMAT_ADPCM;
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) - sizeof(dst.cbSize), suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst) - 1, suggest);
+todo_wine
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+
+    /* Invalid suggest flags */
+    src.wFormatTag = WAVE_FORMAT_PCM;
+    suggest = 0xFFFFFFFF;
+    rc = acmFormatSuggest(NULL, &src, &dst, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_INVALFLAG, "failed with error 0x%x\n", rc);
+
+    /* Invalid source and destination */
+    suggest = 0;
+    rc = acmFormatSuggest(NULL, NULL, &dst, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, &src, NULL, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+    rc = acmFormatSuggest(NULL, NULL, NULL, sizeof(dst), suggest);
+    ok(rc == MMSYSERR_INVALPARAM, "failed with error 0x%x\n", rc);
+}
+
 START_TEST(msacm)
 {
     driver_tests();
     test_prepareheader();
+    test_acmFormatSuggest();
 }
diff --git a/include/mmreg.h b/include/mmreg.h
index 55bfd35ebc0..e0b1dd09c27 100644
--- a/include/mmreg.h
+++ b/include/mmreg.h
@@ -107,6 +107,7 @@ typedef struct _WAVEFORMATEX {
 #define  WAVE_FORMAT_G721_ADPCM			0x0040	/*  Antex Electronics Corporation  */
 #define  WAVE_FORMAT_MPEG			0x0050	/*  Microsoft Corporation  */
 #define  WAVE_FORMAT_MPEGLAYER3			0x0055
+#define  WAVE_FORMAT_MSRT24			0x0082  /*  Microsoft Corporation */
 #define  WAVE_FORMAT_CREATIVE_ADPCM		0x0200	/*  Creative Labs, Inc  */
 #define  WAVE_FORMAT_CREATIVE_FASTSPEECH8	0x0202	/*  Creative Labs, Inc  */
 #define  WAVE_FORMAT_CREATIVE_FASTSPEECH10	0x0203	/*  Creative Labs, Inc  */