[FFmpeg-devel] [PATCH] lavfi/crop: add support to option parsing
Clément Bœsch
ubitux at gmail.com
Sat Dec 15 20:03:12 CET 2012
On Sat, Dec 15, 2012 at 05:03:38PM +0100, Stefano Sabatini wrote:
> Also fix documentation accordingly.
>
> TODO: bump micro
> ---
> doc/filters.texi | 48 +++++++++++++++++++++++-----------
> libavfilter/vf_crop.c | 69 +++++++++++++++++++++++++++++--------------------
> 2 files changed, 74 insertions(+), 43 deletions(-)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 44654fe..a8b6221 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -1518,11 +1518,40 @@ testing purposes.
>
> @section crop
>
> -Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
> +Crop the input video.
>
> -The @var{keep_aspect} parameter is optional, if specified and set to a
> -non-zero value will force the output display aspect ratio to be the
> -same of the input, by changing the output sample aspect ratio.
> +This filter accepts a list of @var{key}=@var{value} pairs as argument,
> +separated by ":". If the key of the first options is omitted, the
NitNote: I remember using ':' instead of ":", we may want to make this
consistent at some point.
> +arguments are interpreted according to the syntax
> + at var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}.
> +
Yet another wording for introducing the shorthand syntax? :)
> +A description of the accepted options follows:
> + at table @option
> + at item w, out_w
> +Set the crop area width. It defaults to @code{iw}.
> +This expression is evaluated only once during the filter
> +configuration.
> +
> + at item h, out_h
> +Set the crop area width. It defaults to @code{ih}.
> +This expression is evaluated only once during the filter
> +configuration.
> +
> + at item x
> +Set the expression for the x top-left coordinate of the cropped area.
> +It defaults to @code{(in_w-out_w)/2}.
> +This expression is evaluated per-frame.
> +
> + at item y
> +Set the expression for the y top-left coordinate of the cropped area.
> +It defaults to @code{(in_h-out_h)/2}.
> +This expression is evaluated per-frame.
> +
> + at item keep_aspect
> +If set to 1 will force the output display aspect ratio
> +to be the same of the input, by changing the output sample aspect
> +ratio. It defaults to 0.
> + at end table
>
I wonder if a good example could be a crop=10:20:30:40:keep_aspect=1, but
the shorthand syntax might need to be introduced differently to avoid any
confusion.
> The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
> expressions containing the following constants:
> @@ -1568,13 +1597,6 @@ timestamp expressed in seconds, NAN if the input timestamp is unknown
>
> @end table
>
> -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.
> -
> -The default value of @var{out_w} is "in_w", and the default value of
> - at var{out_h} is "in_h".
> -
> The expression for @var{out_w} may depend on the value of @var{out_h},
> and the expression for @var{out_h} may depend on @var{out_w}, but they
> cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
> @@ -1585,10 +1607,6 @@ position of the top-left corner of the output (non-cropped) area. They
> are evaluated for each frame. If the evaluated value is not valid, it
> is approximated to the nearest valid value.
>
> -The default value of @var{x} is "(in_w-out_w)/2", and the default
> -value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
> -the center of the input image.
> -
> The expression for @var{x} may depend on @var{y}, and the expression
> for @var{y} may depend on @var{x}.
>
> diff --git a/libavfilter/vf_crop.c b/libavfilter/vf_crop.c
> index d0f464f..d4cb710 100644
> --- a/libavfilter/vf_crop.c
> +++ b/libavfilter/vf_crop.c
> @@ -37,6 +37,7 @@
> #include "libavutil/libm.h"
> #include "libavutil/imgutils.h"
> #include "libavutil/mathematics.h"
> +#include "libavutil/opt.h"
>
> static const char *const var_names[] = {
> "in_w", "iw", ///< width of the input video
> @@ -75,6 +76,7 @@ enum var_name {
> };
>
> typedef struct {
> + const AVClass *class;
> int x; ///< x offset of the non-cropped area with respect to the input area
> int y; ///< y offset of the non-cropped area with respect to the input area
> int w; ///< width of the cropped area
> @@ -85,11 +87,44 @@ typedef struct {
>
> int max_step[4]; ///< max pixel step for each plane, expressed as a number of bytes
> int hsub, vsub; ///< chroma subsampling
> - char x_expr[256], y_expr[256], ow_expr[256], oh_expr[256];
> + char *x_expr, *y_expr, *w_expr, *h_expr;
> AVExpr *x_pexpr, *y_pexpr; /* parsed expressions for x and y */
> double var_values[VAR_VARS_NB];
> } CropContext;
>
> +#define OFFSET(x) offsetof(CropContext, x)
> +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
> +
> +static const AVOption crop_options[] = {
> + { "x", "set the x crop area expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "(in_w-out_w)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "y", "set the y crop area expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "(in_h-out_h)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "out_w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "out_h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
> + { "keep_aspect", "force packed RGB in input and output", OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
> + {NULL}
> +};
Please either align or break lines.
> +
> +AVFILTER_DEFINE_CLASS(crop);
> +
> +static av_cold int init(AVFilterContext *ctx, const char *args)
> +{
> + CropContext *crop = ctx->priv;
> + static const char *shorthand[] = { "w", "h", "x", "y", "keep_aspect", NULL };
> +
> + crop->class = &crop_class;
> + av_opt_set_defaults(crop);
> +
> + return av_opt_set_from_string(crop, args, shorthand, "=", ":");
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + CropContext *crop = ctx->priv;
> + av_opt_free(crop);
> +}
> +
> static int query_formats(AVFilterContext *ctx)
> {
> static const enum AVPixelFormat pix_fmts[] = {
> @@ -123,29 +158,6 @@ static int query_formats(AVFilterContext *ctx)
> return 0;
> }
>
> -static av_cold int init(AVFilterContext *ctx, const char *args)
> -{
> - CropContext *crop = ctx->priv;
> -
> - av_strlcpy(crop->ow_expr, "iw", sizeof(crop->ow_expr));
> - av_strlcpy(crop->oh_expr, "ih", sizeof(crop->oh_expr));
> - av_strlcpy(crop->x_expr, "(in_w-out_w)/2", sizeof(crop->x_expr));
> - av_strlcpy(crop->y_expr, "(in_h-out_h)/2", sizeof(crop->y_expr));
> -
> - if (args)
> - sscanf(args, "%255[^:]:%255[^:]:%255[^:]:%255[^:]:%d", crop->ow_expr, crop->oh_expr, crop->x_expr, crop->y_expr, &crop->keep_aspect);
> -
> - return 0;
> -}
> -
> -static av_cold void uninit(AVFilterContext *ctx)
> -{
> - CropContext *crop = ctx->priv;
> -
> - av_expr_free(crop->x_pexpr); crop->x_pexpr = NULL;
> - av_expr_free(crop->y_pexpr); crop->y_pexpr = NULL;
> -}
> -
> static inline int normalize_double(int *n, double d)
> {
> int ret = 0;
> @@ -189,16 +201,16 @@ static int config_input(AVFilterLink *link)
> crop->hsub = pix_desc->log2_chroma_w;
> crop->vsub = pix_desc->log2_chroma_h;
>
> - if ((ret = av_expr_parse_and_eval(&res, (expr = crop->ow_expr),
> + if ((ret = av_expr_parse_and_eval(&res, (expr = crop->w_expr),
> var_names, crop->var_values,
> NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
> - if ((ret = av_expr_parse_and_eval(&res, (expr = crop->oh_expr),
> + if ((ret = av_expr_parse_and_eval(&res, (expr = crop->h_expr),
> var_names, crop->var_values,
> NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = res;
> /* evaluate again ow as it may depend on oh */
> - if ((ret = av_expr_parse_and_eval(&res, (expr = crop->ow_expr),
> + if ((ret = av_expr_parse_and_eval(&res, (expr = crop->w_expr),
> var_names, crop->var_values,
> NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
> crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
> @@ -207,7 +219,7 @@ static int config_input(AVFilterLink *link)
> 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);
> + crop->w_expr, crop->h_expr);
> return AVERROR(EINVAL);
> }
> crop->w &= ~((1 << crop->hsub) - 1);
> @@ -348,4 +360,5 @@ AVFilter avfilter_vf_crop = {
>
> .inputs = avfilter_vf_crop_inputs,
> .outputs = avfilter_vf_crop_outputs,
> + .priv_class = &crop_class,
> };
Rest LGTM, nice improvement, thanks.
--
Clément B.
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