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>

1 files changed, 13 insertions, 20 deletions

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;
     }