[FFmpeg-devel] [PATCH] avformat/avisynth: fix frameprop version check

[FFmpeg-devel] [PATCH] avformat/avisynth: fix frameprop version check

[Stephen Hutchinson]

Trying to be clever about determining between interface version 8
and 8.1 ended up with pre-8.1 versions of AviSynth+ segfaulting.

The amount of time between interface version 8.1 and 9 is small,
so just restrict the frameprop awareness to version 9 and call it
a day.
---
 libavformat/avisynth.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
index 8bc39869a3..b345f5efe2 100644
--- a/libavformat/avisynth.c
+++ b/libavformat/avisynth.c
@@ -502,24 +502,13 @@ static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st)
     /* Read AviSynth+'s frame properties to set additional info.
      *
      * Due to a bug preventing the C interface from accessing frame
-     * properties in earlier versions of interface version 8, only
-     * enable this if we detect version 8.1 at the minimum. */
+     * properties in earlier versions of interface version 8, and
+     * previous attempts at being clever resulting in pre-8 versions
+     * of AviSynth+ segfaulting, only enable this if we detect
+     * version 9 at the minimum.  Technically, 8.1 works, but the time
+     * distance between 8.1 and 9 is very small, so just restrict it to 9. */
 
-    if (!avs_library.avs_get_env_property) {
-        av_log(s, AV_LOG_TRACE, "%s\n",
-               "avs_get_env_property does not exist in AviSynth library; frame properties won't be checked.");
-        frameprop = false;
-    } else {
-        if (avs_library.avs_get_env_property(avs->env, AVS_AEP_INTERFACE_BUGFIX)) {
-            av_log(s, AV_LOG_TRACE, "%s\n", "Using interface version 8.1 or higher, reading frame properties.");
-            frameprop = true;
-        } else {
-            av_log(s, AV_LOG_TRACE, "%s\n", "Using interface version 8.0, need 8.1+ to read frame properties.");
-            frameprop = false;
-        }
-    }
-
-    if (frameprop = true) {
+    if (avs_library.avs_get_version(avs->clip) >= 9) {
 
         frame  = avs_library.avs_get_frame(avs->clip, framedata);
         avsmap = avs_library.avs_get_frame_props_ro(avs->env, frame);
-- 
2.32.0

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Re: [FFmpeg-devel] [PATCH] avformat/avisynth: fix frameprop version check

[Stephen Hutchinson]

On 2/16/22 7:49 PM, Stephen Hutchinson wrote:
> Trying to be clever about determining between interface version 8
> and 8.1 ended up with pre-8.1 versions of AviSynth+ segfaulting.
> 
> The amount of time between interface version 8.1 and 9 is small,
> so just restrict the frameprop awareness to version 9 and call it
> a day.
> ---
>   libavformat/avisynth.c | 23 ++++++-----------------
>   1 file changed, 6 insertions(+), 17 deletions(-)
> 
> diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
> index 8bc39869a3..b345f5efe2 100644
> --- a/libavformat/avisynth.c
> +++ b/libavformat/avisynth.c
> @@ -502,24 +502,13 @@ static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st)
>       /* Read AviSynth+'s frame properties to set additional info.
>        *
>        * Due to a bug preventing the C interface from accessing frame
> -     * properties in earlier versions of interface version 8, only
> -     * enable this if we detect version 8.1 at the minimum. */
> +     * properties in earlier versions of interface version 8, and
> +     * previous attempts at being clever resulting in pre-8 versions
> +     * of AviSynth+ segfaulting, only enable this if we detect
> +     * version 9 at the minimum.  Technically, 8.1 works, but the time
> +     * distance between 8.1 and 9 is very small, so just restrict it to 9. */
>   
> -    if (!avs_library.avs_get_env_property) {
> -        av_log(s, AV_LOG_TRACE, "%s\n",
> -               "avs_get_env_property does not exist in AviSynth library; frame properties won't be checked.");
> -        frameprop = false;
> -    } else {
> -        if (avs_library.avs_get_env_property(avs->env, AVS_AEP_INTERFACE_BUGFIX)) {
> -            av_log(s, AV_LOG_TRACE, "%s\n", "Using interface version 8.1 or higher, reading frame properties.");
> -            frameprop = true;
> -        } else {
> -            av_log(s, AV_LOG_TRACE, "%s\n", "Using interface version 8.0, need 8.1+ to read frame properties.");
> -            frameprop = false;
> -        }
> -    }
> -
> -    if (frameprop = true) {
> +    if (avs_library.avs_get_version(avs->clip) >= 9) {
>   
>           frame  = avs_library.avs_get_frame(avs->clip, framedata);
>           avsmap = avs_library.avs_get_frame_props_ro(avs->env, frame);

Pushed.
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