diff --git a/media/codec2/components/gav1/C2SoftGav1Dec.cpp b/media/codec2/components/gav1/C2SoftGav1Dec.cpp
index 7bd3358..386e097 100644
--- a/media/codec2/components/gav1/C2SoftGav1Dec.cpp
+++ b/media/codec2/components/gav1/C2SoftGav1Dec.cpp
@@ -36,6 +36,8 @@
 // codecname set and passed in as a compile flag from Android.bp
 constexpr char COMPONENT_NAME[] = CODECNAME;
 
+constexpr size_t kMinInputBufferSize = 2 * 1024 * 1024;
+
 class C2SoftGav1Dec::IntfImpl : public SimpleInterface<void>::BaseParams {
  public:
   explicit IntfImpl(const std::shared_ptr<C2ReflectorHelper> &helper)
@@ -114,8 +116,7 @@
             .build());
 
     addParameter(DefineParam(mMaxInputSize, C2_PARAMKEY_INPUT_MAX_BUFFER_SIZE)
-                     .withDefault(new C2StreamMaxBufferSizeInfo::input(
-                         0u, 320 * 240 * 3 / 4))
+                     .withDefault(new C2StreamMaxBufferSizeInfo::input(0u, kMinInputBufferSize))
                      .withFields({
                          C2F(mMaxInputSize, value).any(),
                      })
@@ -231,9 +232,9 @@
       bool mayBlock, C2P<C2StreamMaxBufferSizeInfo::input> &me,
       const C2P<C2StreamMaxPictureSizeTuning::output> &maxSize) {
     (void)mayBlock;
-    // assume compression ratio of 2
-    me.set().value =
-        (((maxSize.v.width + 63) / 64) * ((maxSize.v.height + 63) / 64) * 3072);
+    // assume compression ratio of 2, but enforce a floor
+    me.set().value = c2_max((((maxSize.v.width + 63) / 64)
+                * ((maxSize.v.height + 63) / 64) * 3072), kMinInputBufferSize);
     return C2R::Ok();
   }
 
diff --git a/media/codec2/components/hevc/C2SoftHevcDec.cpp b/media/codec2/components/hevc/C2SoftHevcDec.cpp
index 5f5b2ef..2a6adca 100644
--- a/media/codec2/components/hevc/C2SoftHevcDec.cpp
+++ b/media/codec2/components/hevc/C2SoftHevcDec.cpp
@@ -34,6 +34,7 @@
 constexpr char COMPONENT_NAME[] = "c2.android.hevc.decoder";
 constexpr uint32_t kDefaultOutputDelay = 8;
 constexpr uint32_t kMaxOutputDelay = 16;
+constexpr size_t kMinInputBufferSize = 2 * 1024 * 1024;
 }  // namespace
 
 class C2SoftHevcDec::IntfImpl : public SimpleInterface<void>::BaseParams {
@@ -108,7 +109,7 @@
 
         addParameter(
                 DefineParam(mMaxInputSize, C2_PARAMKEY_INPUT_MAX_BUFFER_SIZE)
-                .withDefault(new C2StreamMaxBufferSizeInfo::input(0u, 320 * 240 * 3 / 4))
+                .withDefault(new C2StreamMaxBufferSizeInfo::input(0u, kMinInputBufferSize))
                 .withFields({
                     C2F(mMaxInputSize, value).any(),
                 })
@@ -220,8 +221,9 @@
     static C2R MaxInputSizeSetter(bool mayBlock, C2P<C2StreamMaxBufferSizeInfo::input> &me,
                                   const C2P<C2StreamMaxPictureSizeTuning::output> &maxSize) {
         (void)mayBlock;
-        // assume compression ratio of 2
-        me.set().value = (((maxSize.v.width + 63) / 64) * ((maxSize.v.height + 63) / 64) * 3072);
+        // assume compression ratio of 2, but enforce a floor
+        me.set().value = c2_max((((maxSize.v.width + 63) / 64)
+                    * ((maxSize.v.height + 63) / 64) * 3072), kMinInputBufferSize);
         return C2R::Ok();
     }