--- a/libavcodec/x86/fmtconvert.asm
+++ b/libavcodec/x86/fmtconvert.asm
@@ -115,6 +115,85 @@ FLOAT_TO_INT16 sse, 0
FLOAT_TO_INT16 3dnow, 0
%undef cvtps2pi
+;------------------------------------------------------------------------------
+; void ff_float_to_int16_step(int16_t *dst, const float *src, long len, long
step);
+;------------------------------------------------------------------------------
+%macro FLOAT_TO_INT16_STEP 2
+cglobal float_to_int16_step_%1, 4,7,%2, dst, src, len, step, step3, v1, v2
+ add lenq, lenq
+ lea srcq, [srcq+2*lenq]
+ lea step3q, [stepq*3]
+ neg lenq
+.loop:
+%ifidn %1, sse2
+ cvtps2dq m0, [srcq+2*lenq ]
+ cvtps2dq m1, [srcq+2*lenq+16]
+ packssdw m0, m1
+ movd v1d, m0
+ psrldq m0, 4
+ movd v2d, m0
+ psrldq m0, 4
+ mov [dstq], v1w
+ mov [dstq+stepq*4], v2w
+ shr v1d, 16
+ shr v2d, 16
+ mov [dstq+stepq*2], v1w
+ mov [dstq+step3q*2], v2w
+ lea dstq, [dstq+stepq*8]
+ movd v1d, m0
+ psrldq m0, 4
+ movd v2d, m0
+ psrldq m0, 4
