diff --git a/compat/avisynth/avisynth_c_25.h b/compat/avisynth/avisynth_c_25.h
new file mode 100644
index 0000000000..9288761331
--- /dev/null
+++ b/compat/avisynth/avisynth_c_25.h
@@ -0,0 +1,68 @@
+//  Copyright (c) 2011 FFmpegSource Project
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+
+/* these are defines/functions that are used and were changed in the switch to 2.6
+ * and are needed to maintain full compatility with 2.5 */
+
+enum {
+  AVS_CS_YV12_25 = 1<<3 | AVS_CS_YUV | AVS_CS_PLANAR,  // y-v-u, planar
+  AVS_CS_I420_25 = 1<<4 | AVS_CS_YUV | AVS_CS_PLANAR,  // y-u-v, planar
+};
+
+AVSC_INLINE int avs_get_height_p_25(const AVS_VideoFrame * p, int plane) {
+    switch (plane)
+    {
+        case AVS_PLANAR_U: case AVS_PLANAR_V:
+            if (p->pitchUV)
+                return p->height>>1;
+            return 0;
+    }
+    return p->height;}
+
+AVSC_INLINE int avs_get_row_size_p_25(const AVS_VideoFrame * p, int plane) {
+    int r;
+    switch (plane)
+    {
+    case AVS_PLANAR_U: case AVS_PLANAR_V:
+        if (p->pitchUV)
+            return p->row_size>>1;
+        else
+            return 0;
+    case AVS_PLANAR_U_ALIGNED: case AVS_PLANAR_V_ALIGNED:
+        if (p->pitchUV)
+        {
+            r = ((p->row_size+AVS_FRAME_ALIGN-1)&(~(AVS_FRAME_ALIGN-1)) )>>1; // Aligned rowsize
+            if (r < p->pitchUV)
+                return r;
+            return p->row_size>>1;
+        }
+        else
+            return 0;
+    case AVS_PLANAR_Y_ALIGNED:
+        r = (p->row_size+AVS_FRAME_ALIGN-1)&(~(AVS_FRAME_ALIGN-1)); // Aligned rowsize
+        if (r <= p->pitch)
+            return r;
+        return p->row_size;
+    }
+    return p->row_size;
+}
+
+AVSC_INLINE int avs_is_yv12_25(const AVS_VideoInfo * p)
+    { return ((p->pixel_type & AVS_CS_YV12_25) == AVS_CS_YV12_25)||((p->pixel_type & AVS_CS_I420_25) == AVS_CS_I420_25); }
diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
index 8a480ede21..afacf04dd1 100644
--- a/libavformat/avisynth.c
+++ b/libavformat/avisynth.c
@@ -36,6 +36,7 @@
   #include <windows.h>
   #undef EXTERN_C
   #include "compat/avisynth/avisynth_c.h"
+  #include "compat/avisynth/avisynth_c_25.h"
   #define AVISYNTH_LIB "avisynth"
 #else
   #include <dlfcn.h>
@@ -471,9 +472,20 @@ static int avisynth_read_packet_video(AVFormatContext *s, AVPacket *pkt, int dis
     for (i = 0; i < avs->n_planes; i++) {
         plane = avs->planes[i];
         src_p = avs_get_read_ptr_p(frame, plane);
+        pitch = avs_get_pitch_p(frame, plane);
+
+#ifdef _WIN32
+        if (avs_library->avs_get_version(avs->clip) == 3) {
+            rowsize = avs_get_row_size_p_25(frame, plane);
+            planeheight = avs_get_height_p_25(frame, plane);
+        } else {
+            rowsize = avs_get_row_size_p(frame, plane);
+            planeheight = avs_get_height_p(frame, plane);
+        }
+#else
         rowsize = avs_get_row_size_p(frame, plane);
         planeheight = avs_get_height_p(frame, plane);
-        pitch = avs_get_pitch_p(frame, plane);
+#endif
 
         // Flip RGB video.
         if (avs_is_rgb24(avs->vi) || avs_is_rgb(avs->vi)) {
@@ -481,26 +493,7 @@ static int avisynth_read_packet_video(AVFormatContext *s, AVPacket *pkt, int dis
             pitch = -pitch;
         }
 
-    // An issue with avs_bit_blt on 2.5.8 prevents video from working correctly.
-    // This problem doesn't exist for 2.6 and AvxSynth, so enable the workaround
-    // for 2.5.8 only. This only displays the warning and exits if the script has
-    // video. 2.5.8's internal interface version is 3, so avs_get_version allows
-    // it to work only in the circumstance that the interface is 5 or higher (4 is
-    // unused).  There's a strong chance that AvxSynth, having been based on 2.5.8,
-    // would also be identified as interface version 3, but since AvxSynth doesn't
-    // suffer from this problem, special-case it.
-#ifdef _WIN32
-    if (avs_library->avs_get_version(avs->clip) > 3) {
         avs_library->avs_bit_blt(avs->env, dst_p, rowsize, src_p, pitch, rowsize, planeheight);
-    } else {
-        av_log(s, AV_LOG_ERROR, "Video input from AviSynth 2.5.8 is not supported. Please upgrade to 2.6.\n");
-        avs->error = 1;
-        av_freep(&pkt->data);
-        return AVERROR_UNKNOWN;
-    }
-#else
-        avs_library->avs_bit_blt(avs->env, dst_p, rowsize, src_p, pitch, rowsize, planeheight);
-#endif
         dst_p += rowsize * planeheight;
     }