Re: [FFmpeg-devel] [PATCH 2/2] lavfi/setpts: introduce rand() function in expression
On date Friday 2023-12-29 12:51:10 +0100, Stefano Sabatini wrote: > On date Thursday 2023-12-28 22:25:08 +0100, Michael Niedermayer wrote: > > On Thu, Dec 28, 2023 at 07:49:18PM +0100, Stefano Sabatini wrote: > > > On date Thursday 2023-12-28 16:00:57 +0100, Stefano Sabatini wrote: > > > > On date Thursday 2023-12-28 12:02:59 +0100, Andreas Rheinhardt wrote: > > > > > Stefano Sabatini: > > > > > > This is useful to simulate random jitter. > > > > > > --- > > > > > > Changelog| 1 + > > > > > > doc/filters.texi | 10 +- > > > > > > libavfilter/setpts.c | 39 +-- > > > > > > 3 files changed, 43 insertions(+), 7 deletions(-) > > > [...] > > > > > Why is this added here and not in lavu/eval so that it is available > > > > > with > > > > > all expressions? > > > > > > > > There is no specific reason. Sometimes you need to have a control over > > > > the seed, in this case you need to provide the PRNG context. > > > > > > > > For the general case, probably we can place a global LFG in the eval > > > > module and fetch its generated values. > > > > > > Another possible solution in attachment, leveraging the same affine > > > PRNG used in random(). For other use cases you might need to use a > > > high-quality PRNG and this might not be good enough. > > > > > eval.c | 18 +++--- > > > 1 file changed, 15 insertions(+), 3 deletions(-) > > > 94413dcc88e3046b4987715f6c152aeb1c24c703 > > > 0001-lavu-eval-add-randomi-function-to-compute-random-val.patch > > > From 4dc5213b0913a2585f75dfd03b497ca2efc093de Mon Sep 17 00:00:00 2001 > > > From: Stefano Sabatini > > > Date: Thu, 28 Dec 2023 19:09:22 +0100 > > > Subject: [PATCH] lavu/eval: add randomi function to compute random value > > > in > > > interval > > > > probably ok if this is usefull > > > > thx > > Will apply the edited patch in a few days if I see no comments. Applied. ___ 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 2/2] lavfi/setpts: introduce rand() function in expression
On date Thursday 2023-12-28 22:25:08 +0100, Michael Niedermayer wrote:
> On Thu, Dec 28, 2023 at 07:49:18PM +0100, Stefano Sabatini wrote:
> > On date Thursday 2023-12-28 16:00:57 +0100, Stefano Sabatini wrote:
> > > On date Thursday 2023-12-28 12:02:59 +0100, Andreas Rheinhardt wrote:
> > > > Stefano Sabatini:
> > > > > This is useful to simulate random jitter.
> > > > > ---
> > > > > Changelog| 1 +
> > > > > doc/filters.texi | 10 +-
> > > > > libavfilter/setpts.c | 39 +--
> > > > > 3 files changed, 43 insertions(+), 7 deletions(-)
> > [...]
> > > > Why is this added here and not in lavu/eval so that it is available with
> > > > all expressions?
> > >
> > > There is no specific reason. Sometimes you need to have a control over
> > > the seed, in this case you need to provide the PRNG context.
> > >
> > > For the general case, probably we can place a global LFG in the eval
> > > module and fetch its generated values.
> >
> > Another possible solution in attachment, leveraging the same affine
> > PRNG used in random(). For other use cases you might need to use a
> > high-quality PRNG and this might not be good enough.
>
> > eval.c | 18 +++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> > 94413dcc88e3046b4987715f6c152aeb1c24c703
> > 0001-lavu-eval-add-randomi-function-to-compute-random-val.patch
> > From 4dc5213b0913a2585f75dfd03b497ca2efc093de Mon Sep 17 00:00:00 2001
> > From: Stefano Sabatini
> > Date: Thu, 28 Dec 2023 19:09:22 +0100
> > Subject: [PATCH] lavu/eval: add randomi function to compute random value in
> > interval
>
> probably ok if this is usefull
>
> thx
Will apply the edited patch in a few days if I see no comments.
>From c4c9eef66401f930a6428c6889020ff5e65c60d6 Mon Sep 17 00:00:00 2001
From: Stefano Sabatini
Date: Thu, 28 Dec 2023 19:09:22 +0100
Subject: [PATCH 1/2] lavu/eval: add randomi function to compute random value
in interval
---
Changelog| 1 +
doc/utils.texi | 12 +---
libavutil/eval.c | 26 +++---
3 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/Changelog b/Changelog
index 424bfc11af..419075dc56 100644
--- a/Changelog
+++ b/Changelog
@@ -15,6 +15,7 @@ version :
- tiltandshift filter
- qrencode filter and qrencodesrc source
- quirc filter
+- lavu/eval: introduce randomi() function in expressions
version 6.1:
- libaribcaption decoder
diff --git a/doc/utils.texi b/doc/utils.texi
index a0b8d4b62d..0c4f146f4f 100644
--- a/doc/utils.texi
+++ b/doc/utils.texi
@@ -939,9 +939,15 @@ Returns the value of the expression printed.
Prints t with loglevel l
-@item random(x)
-Return a pseudo random value between 0.0 and 1.0. @var{x} is the index of the
-internal variable which will be used to save the seed/state.
+@item random(idx)
+Return a pseudo random value between 0.0 and 1.0. @var{idx} is the
+index of the internal variable which will be used to save the
+seed/state.
+
+@item randomi(idx, min, max)
+Return a pseudo random value in the interval between @var{min} and
+@var{max}. @var{idx} is the index of the internal variable which will
+be used to save the seed/state.
@item root(expr, max)
Find an input value for which the function represented by @var{expr}
diff --git a/libavutil/eval.c b/libavutil/eval.c
index bad9e4ecb8..dc6b3697bc 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -162,7 +162,7 @@ struct AVExpr {
e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
e_sqrt, e_not, e_random, e_hypot, e_gcd,
e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
-e_sgn,
+e_sgn, e_randomi
} type;
double value; // is sign in other types
int const_index;
@@ -228,12 +228,22 @@ static double eval_expr(Parser *p, AVExpr *e)
av_log(p, level, "%f\n", x);
return x;
}
-case e_random:{
-int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
-uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
-r= r*1664525+1013904223;
-p->var[idx]= r;
-return e->value * (r * (1.0/UINT64_MAX));
+
+#define COMPUTE_NEXT_RANDOM()\
+int idx = av_clip(eval_expr(p, e->param[0]), 0, VARS-1); \
+uint64_t r = isnan(p->var[idx]) ? 0 : p->var[idx]; \
+r = r * 1664525 + 1013904223;\
+p->var[idx] = r; \
+
+case e_random: {
+COMPUTE_NEXT_RANDOM();
+return r * (1.0/UINT64_MAX);
+}
+case e_randomi: {
+double min = eval_expr(p, e->param[1]);
+double max = eval_expr(p, e->param[2]);
+COMPUTE_NEXT_RANDOM();
+return min + (max - min) * r / UINT64_MAX;
}
case e_while: {
Re: [FFmpeg-devel] [PATCH 2/2] lavfi/setpts: introduce rand() function in expression
On Thu, Dec 28, 2023 at 07:49:18PM +0100, Stefano Sabatini wrote: > On date Thursday 2023-12-28 16:00:57 +0100, Stefano Sabatini wrote: > > On date Thursday 2023-12-28 12:02:59 +0100, Andreas Rheinhardt wrote: > > > Stefano Sabatini: > > > > This is useful to simulate random jitter. > > > > --- > > > > Changelog| 1 + > > > > doc/filters.texi | 10 +- > > > > libavfilter/setpts.c | 39 +-- > > > > 3 files changed, 43 insertions(+), 7 deletions(-) > [...] > > > Why is this added here and not in lavu/eval so that it is available with > > > all expressions? > > > > There is no specific reason. Sometimes you need to have a control over > > the seed, in this case you need to provide the PRNG context. > > > > For the general case, probably we can place a global LFG in the eval > > module and fetch its generated values. > > Another possible solution in attachment, leveraging the same affine > PRNG used in random(). For other use cases you might need to use a > high-quality PRNG and this might not be good enough. > eval.c | 18 +++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > 94413dcc88e3046b4987715f6c152aeb1c24c703 > 0001-lavu-eval-add-randomi-function-to-compute-random-val.patch > From 4dc5213b0913a2585f75dfd03b497ca2efc093de Mon Sep 17 00:00:00 2001 > From: Stefano Sabatini > Date: Thu, 28 Dec 2023 19:09:22 +0100 > Subject: [PATCH] lavu/eval: add randomi function to compute random value in > interval probably ok if this is usefull thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Never trust a computer, one day, it may think you are the virus. -- Compn 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 2/2] lavfi/setpts: introduce rand() function in expression
On date Thursday 2023-12-28 16:00:57 +0100, Stefano Sabatini wrote:
> On date Thursday 2023-12-28 12:02:59 +0100, Andreas Rheinhardt wrote:
> > Stefano Sabatini:
> > > This is useful to simulate random jitter.
> > > ---
> > > Changelog| 1 +
> > > doc/filters.texi | 10 +-
> > > libavfilter/setpts.c | 39 +--
> > > 3 files changed, 43 insertions(+), 7 deletions(-)
[...]
> > Why is this added here and not in lavu/eval so that it is available with
> > all expressions?
>
> There is no specific reason. Sometimes you need to have a control over
> the seed, in this case you need to provide the PRNG context.
>
> For the general case, probably we can place a global LFG in the eval
> module and fetch its generated values.
Another possible solution in attachment, leveraging the same affine
PRNG used in random(). For other use cases you might need to use a
high-quality PRNG and this might not be good enough.
>From 4dc5213b0913a2585f75dfd03b497ca2efc093de Mon Sep 17 00:00:00 2001
From: Stefano Sabatini
Date: Thu, 28 Dec 2023 19:09:22 +0100
Subject: [PATCH] lavu/eval: add randomi function to compute random value in
interval
---
libavutil/eval.c | 18 +++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/libavutil/eval.c b/libavutil/eval.c
index 344bebbf69..e94597ccf4 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -164,7 +164,7 @@ struct AVExpr {
e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
e_sqrt, e_not, e_random, e_hypot, e_gcd,
e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
-e_sgn,
+e_sgn, e_randomi
} type;
double value; // is sign in other types
int const_index;
@@ -230,13 +230,23 @@ static double eval_expr(Parser *p, AVExpr *e)
av_log(p, level, "%f\n", x);
return x;
}
-case e_random:{
+#define COMPUTE_RANDOM(seed_) (seed_)*1664525+1013904223
+case e_random:{
int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
-r= r*1664525+1013904223;
+r = COMPUTE_RANDOM(r);
p->var[idx]= r;
return e->value * (r * (1.0/UINT64_MAX));
}
+case e_randomi: {
+int idx = av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
+uint64_t r = isnan(p->var[idx]) ? 0 : p->var[idx];
+r = COMPUTE_RANDOM(r);
+p->var[idx] = r;
+double min = eval_expr(p, e->param[1]);
+double max = eval_expr(p, e->param[2]);
+return min + (max - min) * r / UINT64_MAX;
+}
case e_while: {
double d = NAN;
while (eval_expr(p, e->param[0]))
@@ -463,6 +473,7 @@ static int parse_primary(AVExpr **e, Parser *p)
else if (strmatch(next, "pow" )) d->type = e_pow;
else if (strmatch(next, "print" )) d->type = e_print;
else if (strmatch(next, "random")) d->type = e_random;
+else if (strmatch(next, "randomi")) d->type = e_randomi;
else if (strmatch(next, "hypot" )) d->type = e_hypot;
else if (strmatch(next, "gcd" )) d->type = e_gcd;
else if (strmatch(next, "if")) d->type = e_if;
@@ -676,6 +687,7 @@ static int verify_expr(AVExpr *e)
case e_between:
case e_clip:
case e_lerp:
+case e_randomi:
return verify_expr(e->param[0]) &&
verify_expr(e->param[1]) &&
verify_expr(e->param[2]);
--
2.34.1
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Re: [FFmpeg-devel] [PATCH 2/2] lavfi/setpts: introduce rand() function in expression
On date Thursday 2023-12-28 12:02:59 +0100, Andreas Rheinhardt wrote:
> Stefano Sabatini:
> > This is useful to simulate random jitter.
> > ---
> > Changelog| 1 +
> > doc/filters.texi | 10 +-
> > libavfilter/setpts.c | 39 +--
> > 3 files changed, 43 insertions(+), 7 deletions(-)
> >
> > diff --git a/Changelog b/Changelog
> > index 424bfc11af..ed01c53264 100644
> > --- a/Changelog
> > +++ b/Changelog
> > @@ -15,6 +15,7 @@ version :
> > - tiltandshift filter
> > - qrencode filter and qrencodesrc source
> > - quirc filter
> > +- lavfi/setpts: introduce rand() function in expression
> >
> > version 6.1:
> > - libaribcaption decoder
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index d1f95b9781..1d9a5d6c7d 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -30946,7 +30946,7 @@ The expression which is evaluated for each frame to
> > construct its timestamp.
> > @end table
> >
> > The expression is evaluated through the eval API and can contain the
> > following
> > -constants:
> > +constants and functions:
> >
> > @table @option
> > @item FRAME_RATE, FR
> > @@ -31010,6 +31010,8 @@ The timebase of the input timestamps.
> > @item T_CHANGE
> > Time of the first frame after command was applied or time of the first
> > frame if no commands.
> >
> > +@item rand(min, max)
> > +a random number included between min and max
> > @end table
> >
> > @subsection Examples
> > @@ -31021,6 +31023,12 @@ Start counting PTS from zero
> > setpts=PTS-STARTPTS
> > @end example
> >
> > +@item
> > +Apply a random jitter effect of +/-100 TB units:
> > +@example
> > +setpts=PTS+100rand(-100\,100)
> > +@end example
> > +
> > @item
> > Apply fast motion effect:
> > @example
> > diff --git a/libavfilter/setpts.c b/libavfilter/setpts.c
> > index 88a8d6af86..0f24a900b3 100644
> > --- a/libavfilter/setpts.c
> > +++ b/libavfilter/setpts.c
> > @@ -32,6 +32,8 @@
> > #include "libavutil/internal.h"
> > #include "libavutil/mathematics.h"
> > #include "libavutil/opt.h"
> > +#include "libavutil/lfg.h"
> > +#include "libavutil/random_seed.h"
> > #include "libavutil/time.h"
> > #include "audio.h"
> > #include "avfilter.h"
> > @@ -101,18 +103,39 @@ typedef struct SetPTSContext {
> > AVExpr *expr;
> > double var_values[VAR_VARS_NB];
> > enum AVMediaType type;
> > +AVLFG lfg;
> > } SetPTSContext;
> >
> > #define V(name_) \
> > setpts->var_values[VAR_##name_]
> >
> > +static double drand(void *ctx, double min, double max)
> > +{
> > +SetPTSContext *setpts = ((AVFilterContext *)ctx)->priv;
> > +
> > +return min + (max-min) / UINT_MAX * av_lfg_get(>lfg);
> > +}
> > +
[...]
>
> Why is this added here and not in lavu/eval so that it is available with
> all expressions?
There is no specific reason. Sometimes you need to have a control over
the seed, in this case you need to provide the PRNG context.
For the general case, probably we can place a global LFG in the eval
module and fetch its generated values.
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Re: [FFmpeg-devel] [PATCH 2/2] lavfi/setpts: introduce rand() function in expression
Stefano Sabatini:
> This is useful to simulate random jitter.
> ---
> Changelog| 1 +
> doc/filters.texi | 10 +-
> libavfilter/setpts.c | 39 +--
> 3 files changed, 43 insertions(+), 7 deletions(-)
>
> diff --git a/Changelog b/Changelog
> index 424bfc11af..ed01c53264 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -15,6 +15,7 @@ version :
> - tiltandshift filter
> - qrencode filter and qrencodesrc source
> - quirc filter
> +- lavfi/setpts: introduce rand() function in expression
>
> version 6.1:
> - libaribcaption decoder
> diff --git a/doc/filters.texi b/doc/filters.texi
> index d1f95b9781..1d9a5d6c7d 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -30946,7 +30946,7 @@ The expression which is evaluated for each frame to
> construct its timestamp.
> @end table
>
> The expression is evaluated through the eval API and can contain the
> following
> -constants:
> +constants and functions:
>
> @table @option
> @item FRAME_RATE, FR
> @@ -31010,6 +31010,8 @@ The timebase of the input timestamps.
> @item T_CHANGE
> Time of the first frame after command was applied or time of the first frame
> if no commands.
>
> +@item rand(min, max)
> +a random number included between min and max
> @end table
>
> @subsection Examples
> @@ -31021,6 +31023,12 @@ Start counting PTS from zero
> setpts=PTS-STARTPTS
> @end example
>
> +@item
> +Apply a random jitter effect of +/-100 TB units:
> +@example
> +setpts=PTS+100rand(-100\,100)
> +@end example
> +
> @item
> Apply fast motion effect:
> @example
> diff --git a/libavfilter/setpts.c b/libavfilter/setpts.c
> index 88a8d6af86..0f24a900b3 100644
> --- a/libavfilter/setpts.c
> +++ b/libavfilter/setpts.c
> @@ -32,6 +32,8 @@
> #include "libavutil/internal.h"
> #include "libavutil/mathematics.h"
> #include "libavutil/opt.h"
> +#include "libavutil/lfg.h"
> +#include "libavutil/random_seed.h"
> #include "libavutil/time.h"
> #include "audio.h"
> #include "avfilter.h"
> @@ -101,18 +103,39 @@ typedef struct SetPTSContext {
> AVExpr *expr;
> double var_values[VAR_VARS_NB];
> enum AVMediaType type;
> +AVLFG lfg;
> } SetPTSContext;
>
> #define V(name_) \
> setpts->var_values[VAR_##name_]
>
> +static double drand(void *ctx, double min, double max)
> +{
> +SetPTSContext *setpts = ((AVFilterContext *)ctx)->priv;
> +
> +return min + (max-min) / UINT_MAX * av_lfg_get(>lfg);
> +}
> +
> +typedef double (*eval_func2)(void *, double a, double b);
> +
> +static const eval_func2 fun2[] = {
> +drand,
> +NULL
> +};
> +
> +static const char *const fun2_names[] = {
> +"rand"
> +};
> +
> static av_cold int init(AVFilterContext *ctx)
> {
> SetPTSContext *setpts = ctx->priv;
> int ret;
>
> +av_lfg_init(>lfg, av_get_random_seed());
> +
> if ((ret = av_expr_parse(>expr, setpts->expr_str,
> - var_names, NULL, NULL, NULL, NULL, 0, ctx)) <
> 0) {
> + var_names, NULL, NULL, fun2_names, fun2, 0,
> ctx)) < 0) {
> av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",
> setpts->expr_str);
> return ret;
> }
> @@ -126,6 +149,7 @@ static av_cold int init(AVFilterContext *ctx)
> V(STARTPTS)= NAN;
> V(STARTT) = NAN;
> V(T_CHANGE)= NAN;
> +
> return 0;
> }
>
> @@ -159,8 +183,10 @@ static inline char *double2int64str(char *buf, double v)
> return buf;
> }
>
> -static double eval_pts(SetPTSContext *setpts, AVFilterLink *inlink, AVFrame
> *frame, int64_t pts)
> +static double eval_pts(AVFilterContext *ctx, AVFilterLink *inlink, AVFrame
> *frame, int64_t pts)
> {
> +SetPTSContext *setpts = ctx->priv;
> +
> if (isnan(V(STARTPTS))) {
> V(STARTPTS) = TS2D(pts);
> V(STARTT ) = TS2T(pts, inlink->time_base);
> @@ -186,17 +212,18 @@ FF_ENABLE_DEPRECATION_WARNINGS
> }
> }
>
> -return av_expr_eval(setpts->expr, setpts->var_values, NULL);
> +return av_expr_eval(setpts->expr, setpts->var_values, ctx);
> }
> #define d2istr(v) double2int64str((char[BUF_SIZE]){0}, v)
>
> static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
> {
> -SetPTSContext *setpts = inlink->dst->priv;
> +AVFilterContext *ctx = inlink->dst;
> +SetPTSContext *setpts = ctx->priv;
> int64_t in_pts = frame->pts;
> double d;
>
> -d = eval_pts(setpts, inlink, frame, frame->pts);
> +d = eval_pts(ctx, inlink, frame, frame->pts);
> frame->pts = D2TS(d);
>
> av_log(inlink->dst, AV_LOG_TRACE,
> @@ -250,7 +277,7 @@ static int activate(AVFilterContext *ctx)
> return filter_frame(inlink, in);
>
> if (ff_inlink_acknowledge_status(inlink, , )) {
> -double d = eval_pts(setpts, inlink, NULL, pts);
> +double d = eval_pts(ctx, inlink, NULL, pts);
>
> av_log(ctx, AV_LOG_TRACE, "N:EOF PTS:%s T:%f -> PTS:%s T:%f\n",
>
[FFmpeg-devel] [PATCH 2/2] lavfi/setpts: introduce rand() function in expression
This is useful to simulate random jitter.
---
Changelog| 1 +
doc/filters.texi | 10 +-
libavfilter/setpts.c | 39 +--
3 files changed, 43 insertions(+), 7 deletions(-)
diff --git a/Changelog b/Changelog
index 424bfc11af..ed01c53264 100644
--- a/Changelog
+++ b/Changelog
@@ -15,6 +15,7 @@ version :
- tiltandshift filter
- qrencode filter and qrencodesrc source
- quirc filter
+- lavfi/setpts: introduce rand() function in expression
version 6.1:
- libaribcaption decoder
diff --git a/doc/filters.texi b/doc/filters.texi
index d1f95b9781..1d9a5d6c7d 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -30946,7 +30946,7 @@ The expression which is evaluated for each frame to
construct its timestamp.
@end table
The expression is evaluated through the eval API and can contain the following
-constants:
+constants and functions:
@table @option
@item FRAME_RATE, FR
@@ -31010,6 +31010,8 @@ The timebase of the input timestamps.
@item T_CHANGE
Time of the first frame after command was applied or time of the first frame
if no commands.
+@item rand(min, max)
+a random number included between min and max
@end table
@subsection Examples
@@ -31021,6 +31023,12 @@ Start counting PTS from zero
setpts=PTS-STARTPTS
@end example
+@item
+Apply a random jitter effect of +/-100 TB units:
+@example
+setpts=PTS+100rand(-100\,100)
+@end example
+
@item
Apply fast motion effect:
@example
diff --git a/libavfilter/setpts.c b/libavfilter/setpts.c
index 88a8d6af86..0f24a900b3 100644
--- a/libavfilter/setpts.c
+++ b/libavfilter/setpts.c
@@ -32,6 +32,8 @@
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
+#include "libavutil/lfg.h"
+#include "libavutil/random_seed.h"
#include "libavutil/time.h"
#include "audio.h"
#include "avfilter.h"
@@ -101,18 +103,39 @@ typedef struct SetPTSContext {
AVExpr *expr;
double var_values[VAR_VARS_NB];
enum AVMediaType type;
+AVLFG lfg;
} SetPTSContext;
#define V(name_) \
setpts->var_values[VAR_##name_]
+static double drand(void *ctx, double min, double max)
+{
+SetPTSContext *setpts = ((AVFilterContext *)ctx)->priv;
+
+return min + (max-min) / UINT_MAX * av_lfg_get(>lfg);
+}
+
+typedef double (*eval_func2)(void *, double a, double b);
+
+static const eval_func2 fun2[] = {
+drand,
+NULL
+};
+
+static const char *const fun2_names[] = {
+"rand"
+};
+
static av_cold int init(AVFilterContext *ctx)
{
SetPTSContext *setpts = ctx->priv;
int ret;
+av_lfg_init(>lfg, av_get_random_seed());
+
if ((ret = av_expr_parse(>expr, setpts->expr_str,
- var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
+ var_names, NULL, NULL, fun2_names, fun2, 0, ctx))
< 0) {
av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",
setpts->expr_str);
return ret;
}
@@ -126,6 +149,7 @@ static av_cold int init(AVFilterContext *ctx)
V(STARTPTS)= NAN;
V(STARTT) = NAN;
V(T_CHANGE)= NAN;
+
return 0;
}
@@ -159,8 +183,10 @@ static inline char *double2int64str(char *buf, double v)
return buf;
}
-static double eval_pts(SetPTSContext *setpts, AVFilterLink *inlink, AVFrame
*frame, int64_t pts)
+static double eval_pts(AVFilterContext *ctx, AVFilterLink *inlink, AVFrame
*frame, int64_t pts)
{
+SetPTSContext *setpts = ctx->priv;
+
if (isnan(V(STARTPTS))) {
V(STARTPTS) = TS2D(pts);
V(STARTT ) = TS2T(pts, inlink->time_base);
@@ -186,17 +212,18 @@ FF_ENABLE_DEPRECATION_WARNINGS
}
}
-return av_expr_eval(setpts->expr, setpts->var_values, NULL);
+return av_expr_eval(setpts->expr, setpts->var_values, ctx);
}
#define d2istr(v) double2int64str((char[BUF_SIZE]){0}, v)
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
-SetPTSContext *setpts = inlink->dst->priv;
+AVFilterContext *ctx = inlink->dst;
+SetPTSContext *setpts = ctx->priv;
int64_t in_pts = frame->pts;
double d;
-d = eval_pts(setpts, inlink, frame, frame->pts);
+d = eval_pts(ctx, inlink, frame, frame->pts);
frame->pts = D2TS(d);
av_log(inlink->dst, AV_LOG_TRACE,
@@ -250,7 +277,7 @@ static int activate(AVFilterContext *ctx)
return filter_frame(inlink, in);
if (ff_inlink_acknowledge_status(inlink, , )) {
-double d = eval_pts(setpts, inlink, NULL, pts);
+double d = eval_pts(ctx, inlink, NULL, pts);
av_log(ctx, AV_LOG_TRACE, "N:EOF PTS:%s T:%f -> PTS:%s T:%f\n",
d2istr(V(PTS)), V(T), d2istr(d), TS2T(d, inlink->time_base));
--
2.34.1
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