[FFmpeg-devel] [PATCH 4/4] Make the crop filter accept parametric expressions.
Michael Niedermayer
michaelni
Wed Sep 22 22:59:50 CEST 2010
On Tue, Sep 21, 2010 at 10:36:52AM +0200, Stefano Sabatini wrote:
> On date Friday 2010-09-17 12:09:04 +0200, Michael Niedermayer encoded:
> > On Wed, Sep 15, 2010 at 12:28:06AM +0200, Stefano Sabatini wrote:
> > [...]
> > > +static inline int normalize_double(int *n, double d)
> > > +{
> > > + int ret = 0;
> > > +
> > > + if (isnan(d)) {
> > > + ret = AVERROR(EINVAL);
> > > + } else if (d > INT_MAX || d < INT_MIN) {
> > > + *n = d > INT_MAX ? INT_MAX : INT_MIN;
> > > + ret = AVERROR(EINVAL);
> > > + } else
> >
> > > + *n = d;
> >
> > something that rounds to nearest should be used
>
> round()
>
> > > +
> > > + return ret;
> > > +}
> > > +
> > > static int config_input(AVFilterLink *link)
> > > {
> > > AVFilterContext *ctx = link->dst;
> > > CropContext *crop = ctx->priv;
> > > const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[link->format];
> > > + int ret;
> > > + const char *expr;
> > > + double res;
> > > +
> > > + crop->var_values[E] = M_E;
> > > + crop->var_values[PHI] = M_PHI;
> > > + crop->var_values[PI] = M_PI;
> > > + crop->var_values[IN_W] = crop->var_values[IW] = ctx->inputs[0]->w;
> > > + crop->var_values[IN_H] = crop->var_values[IH] = ctx->inputs[0]->h;
> > > + crop->var_values[X] = NAN;
> > > + crop->var_values[Y] = NAN;
> > > + crop->var_values[OUT_W] = crop->var_values[OW] = NAN;
> > > + crop->var_values[OUT_H] = crop->var_values[OH] = NAN;
> > > + crop->var_values[N] = 0;
> >
> > T/POS are random?
>
> Fixed, set now to NAN.
>
> > > av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);
> > > crop->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
> > > crop->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
> > >
> > > - if (crop->w == 0)
> > > - crop->w = link->w - crop->x;
> > > - if (crop->h == 0)
> > > - crop->h = link->h - crop->y;
> > > + if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
> > > + var_names, crop->var_values,
> > > + NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> > > + crop->var_values[OUT_W] = crop->var_values[OW] = res;
> > > + if ((ret = av_parse_and_eval_expr(&res, (expr = crop->oh_expr),
> > > + var_names, crop->var_values,
> > > + NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> > > + crop->var_values[OUT_H] = crop->var_values[OH] = res;
> > > + /* evaluate again ow as it may depend on oh */
> > > + if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
> > > + var_names, crop->var_values,
> > > + NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> > > + crop->var_values[OUT_W] = crop->var_values[OW] = res;
> > > + if (normalize_double(&crop->w, crop->var_values[OUT_W]) < 0 ||
> > > + normalize_double(&crop->h, crop->var_values[OUT_H]) < 0) {
> > > + av_log(ctx, AV_LOG_ERROR,
> > > + "Too big value or invalid expression for out_w/ow or out_h/oh. "
> > > + "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
> > > + crop->ow_expr, crop->oh_expr);
> > > + return AVERROR(EINVAL);
> > > + }
> > > + crop->w &= ~((1 << crop->hsub) - 1);
> > > + crop->h &= ~((1 << crop->vsub) - 1);
> > > +
> > > + if ((ret = av_parse_expr(&crop->x_pexpr, crop->x_expr, var_names,
> > > + NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
> > > + (ret = av_parse_expr(&crop->y_pexpr, crop->y_expr, var_names,
> > > + NULL, NULL, NULL, NULL, 0, ctx)) < 0)
> > > + return AVERROR(EINVAL);
> > >
> > > + crop->var_values[X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
> > > + crop->var_values[Y] = av_eval_expr(crop->y_pexpr, crop->var_values, NULL);
> > > + /* evaluate again x as it may depend on y */
> > > + crop->var_values[X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
> > > + if (normalize_double(&crop->x, crop->var_values[X]) < 0 ||
> > > + normalize_double(&crop->y, crop->var_values[Y]) < 0) {
> > > + av_log(ctx, AV_LOG_ERROR,
> > > + "Too big value or invalid expression for x or y. "
> > > + "Maybe the expression for x:'%s' or for y:'%s' is self-referencing.\n",
> > > + crop->x_expr, crop->y_expr);
> > > + return AVERROR(EINVAL);
> > > + }
> >
> > i dont think that will work they can depend on N/T/POS which should be NAN for W/H
>
> Changed the logic, now x/y is evaluated only in start_frame(), a
> default value is set in case the first evaluated x/y is not valid.
> This way the filter won't fail if the initial value of x/y is not
> invalid (and the last valid value is used).
>
> Regards.
> --
> FFmpeg = Fascinating and Fostering MultiPurpose Extroverse Gnome
> doc/ffmpeg-doc.texi | 8 +-
> doc/filters.texi | 104 ++++++++++++++++++++++-----
> ffmpeg.c | 4 -
> libavfilter/vf_crop.c | 176 +++++++++++++++++++++++++++++++++++++++++-----
> tests/lavfi-regression.sh | 10 +-
> 5 files changed, 254 insertions(+), 48 deletions(-)
> 39c3adc9137408cd71d23329d7c7da16b8abada3 0001-Make-the-crop-filter-accept-parametric-expressions.patch
> From 9330a5223bfeeadd1ffbb1c8e6d39c6d95906812 Mon Sep 17 00:00:00 2001
> From: Stefano Sabatini <stefano.sabatini-lala at poste.it>
> Date: Thu, 9 Sep 2010 01:05:04 +0200
> Subject: [PATCH] Make the crop filter accept parametric expressions.
>
> Also change the syntax of the crop filter, from:
> x:y:w:h
> to
> w:h:x:y
>
> which looks more useful.
> ---
> doc/ffmpeg-doc.texi | 8 +-
> doc/filters.texi | 104 ++++++++++++++++++++++-----
> ffmpeg.c | 4 +-
> libavfilter/vf_crop.c | 176 ++++++++++++++++++++++++++++++++++++++++-----
> tests/lavfi-regression.sh | 10 ++--
> 5 files changed, 254 insertions(+), 48 deletions(-)
>
> diff --git a/doc/ffmpeg-doc.texi b/doc/ffmpeg-doc.texi
> index d9c5c14..e43e87e 100644
> --- a/doc/ffmpeg-doc.texi
> +++ b/doc/ffmpeg-doc.texi
> @@ -226,13 +226,13 @@ The following abbreviations are recognized:
>
> @item -aspect @var{aspect}
> Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
> - at item -croptop @var{size} (deprecated - use -vf crop=x:y:width:height instead)
> + at item -croptop @var{size} (deprecated - use the crop filter instead)
> Set top crop band size (in pixels).
> - at item -cropbottom @var{size} (deprecated - use -vf crop=x:y:width:height instead)
> + at item -cropbottom @var{size} (deprecated - use the crop filter instead)
> Set bottom crop band size (in pixels).
> - at item -cropleft @var{size} (deprecated - use -vf crop=x:y:width:height instead)
> + at item -cropleft @var{size} (deprecated - use the crop filter instead)
> Set left crop band size (in pixels).
> - at item -cropright @var{size} (deprecated - use -vf crop=x:y:width:height instead)
> + at item -cropright @var{size} (deprecated - use the crop filter instead)
> Set right crop band size (in pixels).
> @item -padtop @var{size}
> @item -padbottom @var{size}
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 262116c..209fa2a 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -26,34 +26,102 @@ Below is a description of the currently available video filters.
>
> @section crop
>
> -Crop the input video to @var{x}:@var{y}:@var{width}:@var{height}.
> +Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
>
> - at example
> -./ffmpeg -i in.avi -vf "crop=0:0:0:240" out.avi
> - at end example
> +The parameters are expressions containing the following constants:
>
> - at var{x} and @var{y} specify the position of the top-left corner of the
> -output (non-cropped) area.
> + at table @option
> + at item E, PI, PHI
> +the corresponding mathematical approximated values for e
> +(euler number), pi (greek PI), PHI (golden ratio)
>
> -The default value of @var{x} and @var{y} is 0.
> + at item x, y
> +the computed values for @var{x} and @var{y}. They are evaluated for
> +each new frame.
> +
> + at item in_w, in_h
> +the input width and heigth
> +
> + at item iw, ih
> +same as @var{in_w} and @var{in_h}
> +
> + at item out_w, out_h
> +the output (cropped) width and heigth
> +
> + at item ow, oh
> +same as @var{out_w} and @var{out_h}
> +
> + at item n
> +the number of input frame, starting from 0
> +
> + at item pos
> +the position in the file of the input frame, NAN if unknown
> +
> + at item t
> +timestamp expressed in seconds, NAN if the input timestamp is invalid
is unknown
> +
> + at end table
>
> -The @var{width} and @var{height} parameters specify the width and height
> -of the output (non-cropped) area.
> +The @var{out_w} and @var{out_h} parameters specify the expressions for
> +the width and height of the output (cropped) video. They are
> +evaluated just at the configuration of the filter.
>
> -A value of 0 is interpreted as the maximum possible size contained in
> -the area delimited by the top-left corner at position x:y.
> +The default value of @var{out_w} is "in_w", and the default value of
> + at var{out_h} is "in_h".
>
> -For example the parameters:
> +The expression for @var{out_w} may depend on the value of
> + at var{out_h}, and the expression for @var{out_h} may depend on
> + at var{out_h}, but they cannot depend on @var{y} and @var{y}, as
out_h may depend on out_h ?
> + at var{x} and @var{y} are evaluated are evaluated after @var{out_w} and
> + at var{out_h}.
are evaluated are evaluated
please review your own patch before submitting
thank you
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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