diff --git a/src/devices/lib/amlogic/include/soc/aml-common/aml-pdm-audio.h b/src/devices/lib/amlogic/include/soc/aml-common/aml-pdm-audio.h
index eb49b1e..be9623b 100644
--- a/src/devices/lib/amlogic/include/soc/aml-common/aml-pdm-audio.h
+++ b/src/devices/lib/amlogic/include/soc/aml-common/aml-pdm-audio.h
@@ -31,6 +31,9 @@
   //  must resize in lower 32-bits of address space
   zx_status_t SetBuffer(zx_paddr_t buf, size_t len);
 
+  // Get HW alignment required in the buffer in bytes.
+  static uint32_t GetBufferAlignment() { return 8; }
+
   /*
       Returns offset of dma pointer in the ring buffer
   */
diff --git a/src/media/audio/drivers/aml-g12-pdm/audio-stream-in.cc b/src/media/audio/drivers/aml-g12-pdm/audio-stream-in.cc
index dea6105..348e42b 100644
--- a/src/media/audio/drivers/aml-g12-pdm/audio-stream-in.cc
+++ b/src/media/audio/drivers/aml-g12-pdm/audio-stream-in.cc
@@ -7,6 +7,7 @@
 #include <lib/zx/clock.h>
 #include <math.h>
 
+#include <numeric>
 #include <optional>
 #include <utility>
 
@@ -120,13 +121,18 @@
     return ZX_ERR_NO_MEMORY;
   }
 
-  // Calculate ring buffer size for 1 second of 16-bit, 48kHz.
-  size_t kRingBufferSize = fbl::round_up<size_t, size_t>(
-      kMaxSampleRate * 2 * metadata_.number_of_channels, ZX_PAGE_SIZE);
-  // Initialize the ring buffer
-  InitBuffer(kRingBufferSize);
-
-  lib_->SetBuffer(pinned_ring_buffer_.region(0).phys_addr, pinned_ring_buffer_.region(0).size);
+  // Initial setup of one page of buffer, just to be safe.
+  status = InitBuffer(PAGE_SIZE);
+  if (status != ZX_OK) {
+    zxlogf(ERROR, "%s failed to init buffer %d", __FILE__, status);
+    return status;
+  }
+  status =
+      lib_->SetBuffer(pinned_ring_buffer_.region(0).phys_addr, pinned_ring_buffer_.region(0).size);
+  if (status != ZX_OK) {
+    zxlogf(ERROR, "%s failed to set buffer %d", __FILE__, status);
+    return status;
+  }
 
   InitHw();
 
@@ -166,23 +172,33 @@
 
 zx_status_t AudioStreamIn::GetBuffer(const audio_proto::RingBufGetBufferReq& req,
                                      uint32_t* out_num_rb_frames, zx::vmo* out_buffer) {
-  uint32_t rb_frames = static_cast<uint32_t>(pinned_ring_buffer_.region(0).size) / frame_size_;
-
-  if (req.min_ring_buffer_frames > rb_frames) {
-    zxlogf(ERROR, "%s out of range min rin buffer frames", __FUNCTION__);
-    return ZX_ERR_OUT_OF_RANGE;
+  size_t ring_buffer_size = fbl::round_up<size_t, size_t>(
+      req.min_ring_buffer_frames * frame_size_, std::lcm(frame_size_, lib_->GetBufferAlignment()));
+  size_t out_frames = ring_buffer_size / frame_size_;
+  if (out_frames > std::numeric_limits<uint32_t>::max()) {
+    return ZX_ERR_INVALID_ARGS;
   }
-  zx_status_t status;
+
+  size_t vmo_size = fbl::round_up<size_t, size_t>(ring_buffer_size, PAGE_SIZE);
+  auto status = InitBuffer(vmo_size);
+  if (status != ZX_OK) {
+    zxlogf(ERROR, "%s failed to init buffer %d", __FILE__, status);
+    return status;
+  }
+
   constexpr uint32_t rights = ZX_RIGHT_READ | ZX_RIGHT_WRITE | ZX_RIGHT_MAP | ZX_RIGHT_TRANSFER;
   status = ring_buffer_vmo_.duplicate(rights, out_buffer);
   if (status != ZX_OK) {
     zxlogf(ERROR, "%s failed to duplicate vmo", __FUNCTION__);
     return status;
   }
-
-  *out_num_rb_frames = rb_frames;
-
-  lib_->SetBuffer(pinned_ring_buffer_.region(0).phys_addr, rb_frames * frame_size_);
+  status = lib_->SetBuffer(pinned_ring_buffer_.region(0).phys_addr, ring_buffer_size);
+  if (status != ZX_OK) {
+    zxlogf(ERROR, "%s failed to set buffer %d", __FILE__, status);
+    return status;
+  }
+  // This is safe because of the overflow check we made above.
+  *out_num_rb_frames = static_cast<uint32_t>(out_frames);
   return status;
 }
 
@@ -251,13 +267,13 @@
 }
 
 zx_status_t AudioStreamIn::InitBuffer(size_t size) {
-  zx_status_t status;
-  status = zx_vmo_create_contiguous(bti_.get(), size, 0, ring_buffer_vmo_.reset_and_get_address());
+  pinned_ring_buffer_.Unpin();
+  auto status =
+      zx_vmo_create_contiguous(bti_.get(), size, 0, ring_buffer_vmo_.reset_and_get_address());
   if (status != ZX_OK) {
     zxlogf(ERROR, "%s failed to allocate ring buffer vmo - %d", __func__, status);
     return status;
   }
-
   status = pinned_ring_buffer_.Pin(ring_buffer_vmo_, bti_, ZX_VM_PERM_READ | ZX_VM_PERM_WRITE);
   if (status != ZX_OK) {
     zxlogf(ERROR, "%s failed to pin ring buffer vmo - %d", __func__, status);
diff --git a/src/media/audio/drivers/aml-g12-pdm/test/test.cc b/src/media/audio/drivers/aml-g12-pdm/test/test.cc
index 05a692f..0f2bd6b 100644
--- a/src/media/audio/drivers/aml-g12-pdm/test/test.cc
+++ b/src/media/audio/drivers/aml-g12-pdm/test/test.cc
@@ -9,6 +9,7 @@
 #include <ddktl/protocol/composite.h>
 #include <fake-mmio-reg/fake-mmio-reg.h>
 #include <mock-mmio-reg/mock-mmio-reg.h>
+#include <mock/ddktl/protocol/gpio.h>
 #include <soc/aml-s905d2/s905d2-hw.h>
 #include <zxtest/zxtest.h>
 
@@ -138,6 +139,33 @@
     EXPECT_EQ(step, 12);
   }
 
+  void TestRingBufferSize(uint8_t number_of_channels, uint32_t frames_req,
+                          uint32_t frames_expected) {
+    auto metadata = GetDefaultMetadata();
+    metadata.number_of_channels = number_of_channels;
+    tester_.SetMetadata(&metadata, sizeof(metadata));
+
+    auto stream = audio::SimpleAudioStream::Create<TestAudioStreamIn>();
+    audio_fidl::Device::SyncClient client_wrap(std::move(tester_.FidlClient()));
+    audio_fidl::Device::ResultOf::GetChannel ch = client_wrap.GetChannel();
+    ASSERT_EQ(ch.status(), ZX_OK);
+    audio_fidl::StreamConfig::SyncClient client(std::move(ch->channel));
+    zx::channel local, remote;
+    ASSERT_OK(zx::channel::create(0, &local, &remote));
+    fidl::aligned<audio_fidl::PcmFormat> pcm_format = GetDefaultPcmFormat();
+    pcm_format.value.number_of_channels = number_of_channels;
+    auto builder = audio_fidl::Format::UnownedBuilder();
+    builder.set_pcm_format(fidl::unowned_ptr(&pcm_format));
+    client.CreateRingBuffer(builder.build(), std::move(remote));
+
+    auto vmo = audio_fidl::RingBuffer::Call::GetVmo(zx::unowned_channel(local), frames_req, 0);
+    ASSERT_OK(vmo.status());
+    ASSERT_EQ(vmo.Unwrap()->result.response().num_frames, frames_expected);
+
+    stream->DdkAsyncRemove();
+    EXPECT_TRUE(tester_.Ok());
+    stream->DdkRelease();
+  }
   FakePDev pdev_;
   fake_ddk::Bind tester_;
 };
@@ -155,6 +183,22 @@
   TestMasks(/*channels*/ 2, /*channels_to_use_bitmask*/ 0xff, /*channels_mask*/ 3, /*mute_mask*/ 0);
 }
 
+// With 16 bits samples, frame size is 2 x number of channels bytes.
+// Frames returned are rounded to HW buffer alignment (8 bytes) and frame size.
+TEST_F(AudioStreamInTest, RingBufferSize1) {
+  TestRingBufferSize(2, 1, 2);
+}  // Rounded to HW buffer.
+TEST_F(AudioStreamInTest, RingBufferSize2) {
+  TestRingBufferSize(2, 3, 4);
+}  // Rounded to HW buffer.
+TEST_F(AudioStreamInTest, RingBufferSize3) { TestRingBufferSize(3, 1, 4); }  // Rounded to both.
+TEST_F(AudioStreamInTest, RingBufferSize4) { TestRingBufferSize(3, 3, 4); }  // Rounded to both.
+TEST_F(AudioStreamInTest, RingBufferSize5) {
+  TestRingBufferSize(8, 1, 1);
+}  // Rounded to frame size.
+TEST_F(AudioStreamInTest, RingBufferSize6) {
+  TestRingBufferSize(8, 3, 3);
+}  // Rounded to frame size.
 }  // namespace audio::aml_g12
 
 // Redefine PDevMakeMmioBufferWeak per the recommendation in pdev.h.