diff --git a/Common/Common.vcxproj b/Common/Common.vcxproj
index 4d30455354..181f4cac39 100644
--- a/Common/Common.vcxproj
+++ b/Common/Common.vcxproj
@@ -427,7 +427,6 @@
     <ClInclude Include="..\ext\at3_standalone\pixdesc.h" />
     <ClInclude Include="..\ext\at3_standalone\pixfmt.h" />
     <ClInclude Include="..\ext\at3_standalone\rational.h" />
-    <ClInclude Include="..\ext\at3_standalone\rdft.h" />
     <ClInclude Include="..\ext\at3_standalone\samplefmt.h" />
     <ClInclude Include="..\ext\at3_standalone\sinewin.h" />
     <ClInclude Include="..\ext\at3_standalone\util_internal.h" />
@@ -657,7 +656,6 @@
     <ClCompile Include="..\ext\at3_standalone\opt.c" />
     <ClCompile Include="..\ext\at3_standalone\options.c" />
     <ClCompile Include="..\ext\at3_standalone\rational.c" />
-    <ClCompile Include="..\ext\at3_standalone\rdft.c" />
     <ClCompile Include="..\ext\at3_standalone\samplefmt.c" />
     <ClCompile Include="..\ext\at3_standalone\sinewin.c" />
     <ClCompile Include="..\ext\at3_standalone\utils.c" />
diff --git a/Common/Common.vcxproj.filters b/Common/Common.vcxproj.filters
index 5a5d97000f..b6f0c42cc5 100644
--- a/Common/Common.vcxproj.filters
+++ b/Common/Common.vcxproj.filters
@@ -662,9 +662,6 @@
     <ClInclude Include="..\ext\at3_standalone\rational.h">
       <Filter>ext\at3_standalone</Filter>
     </ClInclude>
-    <ClInclude Include="..\ext\at3_standalone\rdft.h">
-      <Filter>ext\at3_standalone</Filter>
-    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="ABI.cpp" />
@@ -1206,9 +1203,6 @@
     <ClCompile Include="..\ext\at3_standalone\rational.c">
       <Filter>ext\at3_standalone</Filter>
     </ClCompile>
-    <ClCompile Include="..\ext\at3_standalone\rdft.c">
-      <Filter>ext\at3_standalone</Filter>
-    </ClCompile>
     <ClCompile Include="..\ext\at3_standalone\intmath.c">
       <Filter>ext\at3_standalone</Filter>
     </ClCompile>
diff --git a/ext/at3_standalone/avfft.c b/ext/at3_standalone/avfft.c
index 53fc672209..247b063ae8 100644
--- a/ext/at3_standalone/avfft.c
+++ b/ext/at3_standalone/avfft.c
@@ -19,8 +19,7 @@
 #include "attributes.h"
 #include "avfft.h"
 #include "fft.h"
-#include "rdft.h"
-#include "dct.h"
+#include "mem.h"
 
 /* FFT */
 
@@ -88,91 +87,3 @@ av_cold void av_mdct_end(FFTContext *s)
 }
 
 #endif /* CONFIG_MDCT */
-
-#if CONFIG_RDFT
-
-RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans)
-{
-    RDFTContext *s = av_malloc(sizeof(*s));
-
-    if (s && ff_rdft_init(s, nbits, trans))
-        av_freep(&s);
-
-    return s;
-}
-
-void av_rdft_calc(RDFTContext *s, FFTSample *data)
-{
-    s->rdft_calc(s, data);
-}
-
-av_cold void av_rdft_end(RDFTContext *s)
-{
-    if (s) {
-        ff_rdft_end(s);
-        av_free(s);
-    }
-}
-
-#endif /* CONFIG_RDFT */
-
-#if CONFIG_DCT
-
-DCTContext *av_dct_init(int nbits, enum DCTTransformType inverse)
-{
-    DCTContext *s = av_malloc(sizeof(*s));
-
-    if (s && ff_dct_init(s, nbits, inverse))
-        av_freep(&s);
-
-    return s;
-}
-
-void av_dct_calc(DCTContext *s, FFTSample *data)
-{
-    s->dct_calc(s, data);
-}
-
-av_cold void av_dct_end(DCTContext *s)
-{
-    if (s) {
-        ff_dct_end(s);
-        av_free(s);
-    }
-}
-
-#ifdef TEST
-int main(int argc, char **argv)
-{
-    int i;
-#define LEN 1024
-    FFTSample *ref  = av_malloc_array(LEN, sizeof(*ref));
-    FFTSample *data = av_malloc_array(LEN, sizeof(*data));
-    RDFTContext *rdft_context  = av_rdft_init(10, DFT_R2C);
-    RDFTContext *irdft_context = av_rdft_init(10, IDFT_C2R);
-
-    if (!ref || !data || !rdft_context || !irdft_context)
-        return 2;
-    for (i=0; i<LEN; i++) {
-        ref[i] = data[i] = i*456 + 123 + i*i;
-    }
-    av_rdft_calc(rdft_context, data);
-    av_rdft_calc(irdft_context, data);
-
-    for (i=0; i<LEN; i++) {
-        if (fabs(ref[i] - data[i]/LEN*2) > 1) {
-            fprintf(stderr, "Failed at %d (%f %f)\n", i, ref[i], data[i]/LEN*2);
-            return 1;
-        }
-    }
-
-    av_rdft_end(rdft_context);
-    av_rdft_end(irdft_context);
-    av_free(data);
-    av_free(ref);
-
-    return 0;
-}
-#endif
-
-#endif /* CONFIG_DCT */