Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 09-11-2019 09:39 pm, Michael Niedermayer wrote: On Tue, Nov 05, 2019 at 06:35:54PM +0530, Gyan wrote: On 05-11-2019 03:55 pm, Michael Niedermayer wrote: On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: On 05-11-2019 04:35 am, Michael Niedermayer wrote: On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: Helps better identification of expr eval failures. Gyan eval.c| 21 + eval.h| 10 ++ version.h |4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 0001-avutil-eval-add-function-to-track-variable-use.patch From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH] avutil/eval: add function to track variable use Helps avoid multiple evals of cross-referenced expressions and catch the use of non-applicable variables with respect to eval or special mode in filters Maybe you should provide more details of the use case of this, maybe with an example. Because it seems not completely obvious An example of a cross-referenced expression would be 'y=x+rand(10)'. Normally in filters, X would be evaluated first, then Y, then X again. The 2nd eval of X will overwrite the first and can generate a different value. With this func, we can avoid the 2nd eval. I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' variables in frame eval mode (it already supports dynamic output based on incoming frame changes) and I would like to catch their presence in init mode, since av_expr_eval will fail. Now, it can also fail due to circularly referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to detect whether it's this case or if inapplicable variables have been used. please add this (or similar information) to the commit message Done. Thanks, Gyan eval.c| 21 + eval.h| 10 ++ version.h |4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 740f6166ddb4b1a581aee7c34edd05d328265df1 v2-0001-avutil-eval-add-function-to-track-variable-use.patch From 2931fa96b8e7f80581ded280907655753e54def0 Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH v2 1/2] avutil/eval: add function to track variable use i think the patch is ok but i think nicolas wants to wait with pushing this until there is a 2nd patch which uses the new function Scale patch posted - https://patchwork.ffmpeg.org/patch/16222/ Gyan ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 09-11-2019 09:39 pm, Michael Niedermayer wrote: On Tue, Nov 05, 2019 at 06:35:54PM +0530, Gyan wrote: On 05-11-2019 03:55 pm, Michael Niedermayer wrote: On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: On 05-11-2019 04:35 am, Michael Niedermayer wrote: On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: Helps better identification of expr eval failures. Gyan eval.c| 21 + eval.h| 10 ++ version.h |4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 0001-avutil-eval-add-function-to-track-variable-use.patch From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH] avutil/eval: add function to track variable use Helps avoid multiple evals of cross-referenced expressions and catch the use of non-applicable variables with respect to eval or special mode in filters Maybe you should provide more details of the use case of this, maybe with an example. Because it seems not completely obvious An example of a cross-referenced expression would be 'y=x+rand(10)'. Normally in filters, X would be evaluated first, then Y, then X again. The 2nd eval of X will overwrite the first and can generate a different value. With this func, we can avoid the 2nd eval. I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' variables in frame eval mode (it already supports dynamic output based on incoming frame changes) and I would like to catch their presence in init mode, since av_expr_eval will fail. Now, it can also fail due to circularly referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to detect whether it's this case or if inapplicable variables have been used. please add this (or similar information) to the commit message Done. Thanks, Gyan eval.c| 21 + eval.h| 10 ++ version.h |4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 740f6166ddb4b1a581aee7c34edd05d328265df1 v2-0001-avutil-eval-add-function-to-track-variable-use.patch From 2931fa96b8e7f80581ded280907655753e54def0 Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH v2 1/2] avutil/eval: add function to track variable use i think the patch is ok but i think nicolas wants to wait with pushing this until there is a 2nd patch which uses the new function OK, my scale patch is ready; will submit that in a couple of days, after some more testing. Thanks, Gyan ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On Tue, Nov 05, 2019 at 06:35:54PM +0530, Gyan wrote: > > > On 05-11-2019 03:55 pm, Michael Niedermayer wrote: > >On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: > >> > >>On 05-11-2019 04:35 am, Michael Niedermayer wrote: > >>>On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: > Helps better identification of expr eval failures. > > Gyan > eval.c| 21 + > eval.h| 10 ++ > version.h |4 ++-- > 3 files changed, 33 insertions(+), 2 deletions(-) > 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 > 0001-avutil-eval-add-function-to-track-variable-use.patch > From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 > From: Gyan Doshi > Date: Sat, 2 Nov 2019 20:16:42 +0530 > Subject: [PATCH] avutil/eval: add function to track variable use > > Helps avoid multiple evals of cross-referenced expressions > and catch the use of non-applicable variables with respect > to eval or special mode in filters > >>>Maybe you should provide more details of the use case of this, maybe > >>>with an example. Because it seems not completely obvious > >>An example of a cross-referenced expression would be 'y=x+rand(10)'. > >>Normally in filters, X would be evaluated first, then Y, then X again. The > >>2nd eval of X will overwrite the first and can generate a different value. > >>With this func, we can avoid the 2nd eval. > >> > >>I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' > >>variables in frame eval mode (it already supports dynamic output based on > >>incoming frame changes) and I would like to catch their presence in init > >>mode, since av_expr_eval will fail. Now, it can also fail due to circularly > >>referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to > >>detect whether it's this case or if inapplicable variables have been used. > >please add this (or similar information) to the commit message > > Done. > > Thanks, > Gyan > eval.c| 21 + > eval.h| 10 ++ > version.h |4 ++-- > 3 files changed, 33 insertions(+), 2 deletions(-) > 740f6166ddb4b1a581aee7c34edd05d328265df1 > v2-0001-avutil-eval-add-function-to-track-variable-use.patch > From 2931fa96b8e7f80581ded280907655753e54def0 Mon Sep 17 00:00:00 2001 > From: Gyan Doshi > Date: Sat, 2 Nov 2019 20:16:42 +0530 > Subject: [PATCH v2 1/2] avutil/eval: add function to track variable use i think the patch is ok but i think nicolas wants to wait with pushing this until there is a 2nd patch which uses the new function Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB In fact, the RIAA has been known to suggest that students drop out of college or go to community college in order to be able to afford settlements. -- The RIAA signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 05-11-2019 06:35 pm, Gyan wrote: On 05-11-2019 03:55 pm, Michael Niedermayer wrote: On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: On 05-11-2019 04:35 am, Michael Niedermayer wrote: On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: Helps better identification of expr eval failures. Gyan eval.c | 21 + eval.h | 10 ++ version.h | 4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 0001-avutil-eval-add-function-to-track-variable-use.patch From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH] avutil/eval: add function to track variable use Helps avoid multiple evals of cross-referenced expressions and catch the use of non-applicable variables with respect to eval or special mode in filters Maybe you should provide more details of the use case of this, maybe with an example. Because it seems not completely obvious An example of a cross-referenced expression would be 'y=x+rand(10)'. Normally in filters, X would be evaluated first, then Y, then X again. The 2nd eval of X will overwrite the first and can generate a different value. With this func, we can avoid the 2nd eval. I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' variables in frame eval mode (it already supports dynamic output based on incoming frame changes) and I would like to catch their presence in init mode, since av_expr_eval will fail. Now, it can also fail due to circularly referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to detect whether it's this case or if inapplicable variables have been used. please add this (or similar information) to the commit message Done. Ping. Gyan ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 05-11-2019 07:40 pm, Nicolas George wrote: Gyan (12019-11-05): An example of a cross-referenced expression would be 'y=x+rand(10)'. Normally in filters, X would be evaluated first, then Y, then X again. The 2nd eval of X will overwrite the first and can generate a different value. With this func, we can avoid the 2nd eval. I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' variables in frame eval mode (it already supports dynamic output based on incoming frame changes) and I would like to catch their presence in init mode, since av_expr_eval will fail. Now, it can also fail due to circularly referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to detect whether it's this case or if inapplicable variables have been used. Then I would prefer that we wait for that to be done and working to commit this patch. After all, it is entirely possible that you realize this is not exactly what you need to achieve your goal. I've looked for workarounds using existing API and I haven't found one. In my scale patch, I've implemented this function locally and it fulfills the role. Thought I should insert it generically. Also, you may consider if it would be worthwhile to globally improve the expression system: maybe have a context with dedicated structure to define the variables and custom functions instead of just arrays that needs to have the same size The scale filter is not the only one with multiple expression evaluation, it would be a waste if the simplification was not applicable to all cases easily. I have come across the need for this helper in other filters like the various draw* filters but it was never a priority. But the changes to scale/scale2ref filter need it or its equivalent. This one does the trick and I can see how it would be helpful in animation support for drawbox where all vars can refer to each other, so each expression is evaluated 5 times. That work is half-way done and is my next focus. (Also, the possibility to define user variables would be nice. But that would require re-writing most of the parser. It needs doing anyway, but it is a huge work.) That sounds desirable but that needs careful design in terms of sanitation of user input. That looks to be a job for another day. Possibly, early next year. Thanks, Gyan ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
Gyan (12019-11-05): > An example of a cross-referenced expression would be 'y=x+rand(10)'. > Normally in filters, X would be evaluated first, then Y, then X again. The > 2nd eval of X will overwrite the first and can generate a different value. > With this func, we can avoid the 2nd eval. > > I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' > variables in frame eval mode (it already supports dynamic output based on > incoming frame changes) and I would like to catch their presence in init > mode, since av_expr_eval will fail. Now, it can also fail due to circularly > referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to > detect whether it's this case or if inapplicable variables have been used. Then I would prefer that we wait for that to be done and working to commit this patch. After all, it is entirely possible that you realize this is not exactly what you need to achieve your goal. Also, you may consider if it would be worthwhile to globally improve the expression system: maybe have a context with dedicated structure to define the variables and custom functions instead of just arrays that needs to have the same size. The scale filter is not the only one with multiple expression evaluation, it would be a waste if the simplification was not applicable to all cases easily. (Also, the possibility to define user variables would be nice. But that would require re-writing most of the parser. It needs doing anyway, but it is a huge work.) Regards, -- Nicolas George signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 05-11-2019 03:55 pm, Michael Niedermayer wrote:
On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote:
On 05-11-2019 04:35 am, Michael Niedermayer wrote:
On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote:
Helps better identification of expr eval failures.
Gyan
eval.c| 21 +
eval.h| 10 ++
version.h |4 ++--
3 files changed, 33 insertions(+), 2 deletions(-)
3dd142baa0144fd324eb9da8a9932cfd7ab2cd98
0001-avutil-eval-add-function-to-track-variable-use.patch
From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001
From: Gyan Doshi
Date: Sat, 2 Nov 2019 20:16:42 +0530
Subject: [PATCH] avutil/eval: add function to track variable use
Helps avoid multiple evals of cross-referenced expressions
and catch the use of non-applicable variables with respect
to eval or special mode in filters
Maybe you should provide more details of the use case of this, maybe
with an example. Because it seems not completely obvious
An example of a cross-referenced expression would be 'y=x+rand(10)'.
Normally in filters, X would be evaluated first, then Y, then X again. The
2nd eval of X will overwrite the first and can generate a different value.
With this func, we can avoid the 2nd eval.
I'm in the process of modifying the scale filter to allow 'n', 't', 'pos'
variables in frame eval mode (it already supports dynamic output based on
incoming frame changes) and I would like to catch their presence in init
mode, since av_expr_eval will fail. Now, it can also fail due to circularly
referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to
detect whether it's this case or if inapplicable variables have been used.
please add this (or similar information) to the commit message
Done.
Thanks,
Gyan
From 2931fa96b8e7f80581ded280907655753e54def0 Mon Sep 17 00:00:00 2001
From: Gyan Doshi
Date: Sat, 2 Nov 2019 20:16:42 +0530
Subject: [PATCH v2 1/2] avutil/eval: add function to track variable use
1)Some filters allow cross-referenced expressions e.g. x=y+10. In
such cases, filters evaluate expressions multiple times for
successful evaluation of all expressions. If the expression for one or
more variables contains a RNG, the result may vary across evaluation
leading to inconsistent values across the cross-referenced expressions.
2)A related case is circular expressions e.g. x=y+10 and y=x+10 which
cannot be succesfully resolved.
3)Certain filter variables may only be applicable in specific eval modes
and lead to a failure of evaluation in other modes e.g. pts is only relevant
for frame eval mode.
At present, there is no reliable means to identify these occurrences and
thus the error messages provided are broad or inaccurate. The helper
function introduced - av_expr_count_var - allows developers to identify
the use of one or more variables in expressions and thus tailor the error
message or allow for a graceful fallback.
---
libavutil/eval.c| 21 +
libavutil/eval.h| 10 ++
libavutil/version.h | 4 ++--
3 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/libavutil/eval.c b/libavutil/eval.c
index 48832979e2..ed0fe636f7 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -735,6 +735,27 @@ end:
return ret;
}
+int av_expr_count_var(AVExpr *e, int var_start, int var_end)
+{
+int i, count = 0;
+
+if (var_start >= var_end)
+return AVERROR(EINVAL);
+
+if (!e)
+return AVERROR(EINVAL);
+
+for (i = 0; e->type != e_const && i < 3 && e->param[i]; i++)
+count += av_expr_count_var(e->param[i], var_start, var_end);
+
+if (e->type == e_const &&
+e->a.const_index >= var_start &&
+e->a.const_index < var_end)
+count++;
+
+return count;
+}
+
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
{
Parser p = { 0 };
diff --git a/libavutil/eval.h b/libavutil/eval.h
index dacd22b96e..030e5617cc 100644
--- a/libavutil/eval.h
+++ b/libavutil/eval.h
@@ -86,6 +86,16 @@ int av_expr_parse(AVExpr **expr, const char *s,
*/
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque);
+/**
+ * Return the number of occurrences of variables within a range in a parsed
expression
+ *
+ * @param var_start index of the start of the range of variables being seached
for in the const_names identifiers
+ * @param var_end index of the first variable after the range of variables
being seached for in the const_names identifiers
+ * @return the number of occurrences of the variables in the range, a negative
value indicates that no expression was passed
+ * or the range wasn't strictly monotonic
+ */
+int av_expr_count_var(AVExpr *e, int var_start, int var_end);
+
/**
* Free a parsed expression previously created with av_expr_parse().
*/
diff --git a/libavutil/version.h b/libavutil/version.h
index 27d663baf1..af3abf7265 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,8 +79,8 @@
*/
#define
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: > > > On 05-11-2019 04:35 am, Michael Niedermayer wrote: > >On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: > >>Helps better identification of expr eval failures. > >> > >>Gyan > >> eval.c| 21 + > >> eval.h| 10 ++ > >> version.h |4 ++-- > >> 3 files changed, 33 insertions(+), 2 deletions(-) > >>3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 > >>0001-avutil-eval-add-function-to-track-variable-use.patch > >> From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 > >>From: Gyan Doshi > >>Date: Sat, 2 Nov 2019 20:16:42 +0530 > >>Subject: [PATCH] avutil/eval: add function to track variable use > >> > >>Helps avoid multiple evals of cross-referenced expressions > >>and catch the use of non-applicable variables with respect > >>to eval or special mode in filters > >Maybe you should provide more details of the use case of this, maybe > >with an example. Because it seems not completely obvious > > An example of a cross-referenced expression would be 'y=x+rand(10)'. > Normally in filters, X would be evaluated first, then Y, then X again. The > 2nd eval of X will overwrite the first and can generate a different value. > With this func, we can avoid the 2nd eval. > > I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' > variables in frame eval mode (it already supports dynamic output based on > incoming frame changes) and I would like to catch their presence in init > mode, since av_expr_eval will fail. Now, it can also fail due to circularly > referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to > detect whether it's this case or if inapplicable variables have been used. please add this (or similar information) to the commit message thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Opposition brings concord. Out of discord comes the fairest harmony. -- Heraclitus signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On 05-11-2019 04:35 am, Michael Niedermayer wrote: On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: Helps better identification of expr eval failures. Gyan eval.c| 21 + eval.h| 10 ++ version.h |4 ++-- 3 files changed, 33 insertions(+), 2 deletions(-) 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 0001-avutil-eval-add-function-to-track-variable-use.patch From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Sat, 2 Nov 2019 20:16:42 +0530 Subject: [PATCH] avutil/eval: add function to track variable use Helps avoid multiple evals of cross-referenced expressions and catch the use of non-applicable variables with respect to eval or special mode in filters Maybe you should provide more details of the use case of this, maybe with an example. Because it seems not completely obvious An example of a cross-referenced expression would be 'y=x+rand(10)'. Normally in filters, X would be evaluated first, then Y, then X again. The 2nd eval of X will overwrite the first and can generate a different value. With this func, we can avoid the 2nd eval. I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' variables in frame eval mode (it already supports dynamic output based on incoming frame changes) and I would like to catch their presence in init mode, since av_expr_eval will fail. Now, it can also fail due to circularly referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to detect whether it's this case or if inapplicable variables have been used. Regards, Gyan ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] avutil/eval: add function to track variable use
On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: > > Helps better identification of expr eval failures. > > Gyan > eval.c| 21 + > eval.h| 10 ++ > version.h |4 ++-- > 3 files changed, 33 insertions(+), 2 deletions(-) > 3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 > 0001-avutil-eval-add-function-to-track-variable-use.patch > From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 > From: Gyan Doshi > Date: Sat, 2 Nov 2019 20:16:42 +0530 > Subject: [PATCH] avutil/eval: add function to track variable use > > Helps avoid multiple evals of cross-referenced expressions > and catch the use of non-applicable variables with respect > to eval or special mode in filters Maybe you should provide more details of the use case of this, maybe with an example. Because it seems not completely obvious thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I know you won't believe me, but the highest form of Human Excellence is to question oneself and others. -- Socrates signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
