avisynth: Support video input from AviSynth 2.5 properly.

Uses the 2.5 compatibility header included with the variant of
FFMS2 that uses AviSynth's C-interface. A copy of this header is
now provided in compat/avisynth.

avs_get_row_size_p and avs_get_height_p changed between versions
2.5 and 2.6. Since the avisynth_c.h header that avformat uses
assumes AviSynth 2.6, it would cause 2.5 to crash if given any
kind of real video (the Version() function was known to work,
though).

AvxSynth was unaffected by this issue because, despite being based
on AviSynth 2.5.8 and using 2.5.8's interface version number of 3,
it actually uses 2.6's versions of these functions.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

compat/avisynth/avisynth_c_25.h

+//  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); }

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;
     }