scale: make the filter parametric

Make the filter accept parametric expressions for the output video size.

Stefano Sabatini committed 15 years ago

Commit d496d331 parent 25601bc3 files · +140 −15Browse files

Unified · Split

3 files

doc/filters.texi +55 −5
libavfilter/avfilter.h +1 −1
libavfilter/vf_scale.c +84 −9

@@ -1004,13 +1004,33 @@ can be used to test the monowhite pixel format descriptor definition. · 1003 unmodified lines
1004		1004
1005	Scale the input video to @var{width}:@var{height} and/or convert the image format.	1005	Scale the input video to @var{width}:@var{height} and/or convert the image format.
1006		1006
1007	For example the command:	1007	The parameters @var{width} and @var{height} are expressions containing
		1008	the following constants:
1008		1009
1009	@example	1010	@table @option
1010	./ffmpeg -i in.avi -vf "scale=200:100" out.avi	1011	@item E, PI, PHI
1011	@end example	1012	the corresponding mathematical approximated values for e
		1013	(euler number), pi (greek PI), phi (golden ratio)
		1014
		1015	@item in_w, in_h
		1016	the input width and heigth
		1017
		1018	@item iw, ih
		1019	same as @var{in_w} and @var{in_h}
1012		1020
1013	will scale the input video to a size of 200x100.	1021	@item out_w, out_h
		1022	the output (cropped) width and heigth
		1023
		1024	@item ow, oh
		1025	same as @var{out_w} and @var{out_h}
		1026
		1027	@item a
		1028	input display aspect ratio, same as @var{iw} / @var{ih}
		1029
		1030	@item hsub, vsub
		1031	horizontal and vertical chroma subsample values. For example for the
		1032	pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
		1033	@end table
1014		1034
1015	If the input image format is different from the format requested by	1035	If the input image format is different from the format requested by
1016	the next filter, the scale filter will convert the input to the	1036	the next filter, the scale filter will convert the input to the
@@ -1025,6 +1045,36 @@ ratio of the input image. · 8 unmodified lines
1025		1045
1026	The default value of @var{width} and @var{height} is 0.	1046	The default value of @var{width} and @var{height} is 0.
1027		1047
		1048	Some examples follow:
		1049	@example
		1050	# scale the input video to a size of 200x100.
		1051	scale=200:100
		1052
		1053	# scale the input to 2x
		1054	scale=2iw:2ih
		1055	# the above is the same as
		1056	scale=2in_w:2in_h
		1057
		1058	# scale the input to half size
		1059	scale=iw/2:ih/2
		1060
		1061	# increase the width, and set the height to the same size
		1062	scale=3/2*iw:ow
		1063
		1064	# seek for Greek harmony
		1065	scale=iw:1/PHI*iw
		1066	scale=ih*PHI:ih
		1067
		1068	# increase the height, and set the width to 3/2 of the height
		1069	scale=3/2oh:3/5ih
		1070
		1071	# increase the size, but make the size a multiple of the chroma
		1072	scale="trunc(3/2iw/hsub)hsub:trunc(3/2ih/vsub)vsub"
		1073
		1074	# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
		1075	scale='min(500\, iw*3/2):-1'
		1076	@end example
		1077
1028	@anchor{setdar}	1078	@anchor{setdar}
1029	@section setdar	1079	@section setdar
1030		1080

libavfilter/avfilter.h+1−1

@@ -27,7 +27,7 @@ · 26 unmodified lines
27		27
28	#define LIBAVFILTER_VERSION_MAJOR 1	28	#define LIBAVFILTER_VERSION_MAJOR 1
29	#define LIBAVFILTER_VERSION_MINOR 77	29	#define LIBAVFILTER_VERSION_MINOR 77
30	#define LIBAVFILTER_VERSION_MICRO 0	30	#define LIBAVFILTER_VERSION_MICRO 1
31		31
32	#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \	32	#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
33	LIBAVFILTER_VERSION_MINOR, \	33	LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_scale.c+84−9

@@ -24,10 +24,40 @@ · 23 unmodified lines
24	*/	24	*/
25		25
26	#include "avfilter.h"	26	#include "avfilter.h"
		27	#include "libavutil/avstring.h"
		28	#include "libavutil/eval.h"
27	#include "libavutil/pixdesc.h"	29	#include "libavutil/pixdesc.h"
28	#include "libavutil/avassert.h"	30	#include "libavutil/avassert.h"
29	#include "libswscale/swscale.h"	31	#include "libswscale/swscale.h"
30		32
		33	static const char *var_names[] = {
		34	"PI",
		35	"PHI",
		36	"E",
		37	"in_w", "iw",
		38	"in_h", "ih",
		39	"out_w", "ow",
		40	"out_h", "oh",
		41	"a",
		42	"hsub",
		43	"vsub",
		44	NULL
		45	};
		46
		47	enum var_name {
		48	VAR_PI,
		49	VAR_PHI,
		50	VAR_E,
		51	VAR_IN_W, VAR_IW,
		52	VAR_IN_H, VAR_IH,
		53	VAR_OUT_W, VAR_OW,
		54	VAR_OUT_H, VAR_OH,
		55	VAR_A,
		56	VAR_HSUB,
		57	VAR_VSUB,
		58	VARS_NB
		59	};
		60
31	typedef struct {	61	typedef struct {
32	struct SwsContext *sws; ///< software scaler context	62	struct SwsContext *sws; ///< software scaler context
33	struct SwsContext *isws[2]; ///< software scaler context for interlaced material	63	struct SwsContext *isws[2]; ///< software scaler context for interlaced material
@@ -44,6 +74,9 @@ typedef struct { · 10 unmodified lines
44	int slice_y; ///< top of current output slice	74	int slice_y; ///< top of current output slice
45	int input_is_pal; ///< set to 1 if the input format is paletted	75	int input_is_pal; ///< set to 1 if the input format is paletted
46	int interlaced;	76	int interlaced;
		77
		78	char w_expr[256]; ///< width expression string
		79	char h_expr[256]; ///< height expression string
47	} ScaleContext;	80	} ScaleContext;
48		81
49	static av_cold int init(AVFilterContext ctx, const char args, void *opaque)	82	static av_cold int init(AVFilterContext ctx, const char args, void *opaque)
@@ -51,9 +84,12 @@ static av_cold int init(AVFilterContext ctx, const char args, void *opaque) · 1 unmodified line
51	ScaleContext *scale = ctx->priv;	84	ScaleContext *scale = ctx->priv;
52	const char *p;	85	const char *p;
53		86
		87	av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
		88	av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
		89
54	scale->flags = SWS_BILINEAR;	90	scale->flags = SWS_BILINEAR;
55	if (args) {	91	if (args) {
56	sscanf(args, "%d:%d", &scale->w, &scale->h);	92	sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
57	p = strstr(args,"flags=");	93	p = strstr(args,"flags=");
58	if (p) scale->flags = strtoul(p+6, NULL, 0);	94	if (p) scale->flags = strtoul(p+6, NULL, 0);
59	if(strstr(args,"interl=1")){	95	if(strstr(args,"interl=1")){
@@ -62,14 +98,6 @@ static av_cold int init(AVFilterContext ctx, const char args, void *opaque) · 2 unmodified lines
62	scale->interlaced=-1;	98	scale->interlaced=-1;
63	}	99	}
64		100
65	/* sanity check params */
66	if (scale->w < -1 \|\| scale->h < -1) {
67	av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
68	return AVERROR(EINVAL);
69	}
70	if (scale->w == -1 && scale->h == -1)
71	scale->w = scale->h = 0;
72
73	return 0;	101	return 0;
74	}	102	}
75		103
@@ -118,6 +146,48 @@ static int config_props(AVFilterLink *outlink) · 42 unmodified lines
118	AVFilterLink *inlink = outlink->src->inputs[0];	146	AVFilterLink *inlink = outlink->src->inputs[0];
119	ScaleContext *scale = ctx->priv;	147	ScaleContext *scale = ctx->priv;
120	int64_t w, h;	148	int64_t w, h;
		149	double var_values[VARS_NB], res;
		150	char *expr;
		151	int ret;
		152
		153	var_values[VAR_PI] = M_PI;
		154	var_values[VAR_PHI] = M_PHI;
		155	var_values[VAR_E] = M_E;
		156	var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
		157	var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
		158	var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
		159	var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
		160	var_values[VAR_A] = (float) inlink->w / inlink->h;
		161	var_values[VAR_HSUB] = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
		162	var_values[VAR_VSUB] = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
		163
		164	/* evaluate width and height */
		165	av_expr_parse_and_eval(&res, (expr = scale->w_expr),
		166	var_names, var_values,
		167	NULL, NULL, NULL, NULL, NULL, 0, ctx);
		168	scale->w = var_values[VAR_OW] = res;
		169	if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
		170	var_names, var_values,
		171	NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
		172	goto fail;
		173	scale->h = var_values[VAR_OH] = res;
		174	/* evaluate again the width, as it may depend on the output height */
		175	if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
		176	var_names, var_values,
		177	NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
		178	goto fail;
		179	scale->w = res;
		180
		181	w = scale->w;
		182	h = scale->h;
		183
		184	/* sanity check params */
		185	if (w < -1 \|\| h < -1) {
		186	av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
		187	return AVERROR(EINVAL);
		188	}
		189	if (w == -1 && h == -1)
		190	scale->w = scale->h = 0;
121		191
122	if (!(w = scale->w))	192	if (!(w = scale->w))
123	w = inlink->w;	193	w = inlink->w;
@@ -159,6 +229,11 @@ static int config_props(AVFilterLink *outlink) · 35 unmodified lines
159	return AVERROR(EINVAL);	229	return AVERROR(EINVAL);
160		230
161	return 0;	231	return 0;
		232
		233	fail:
		234	av_log(NULL, AV_LOG_ERROR,
		235	"Error when evaluating the expression '%s'\n", expr);
		236	return ret;
162	}	237	}
163		238
164	static void start_frame(AVFilterLink link, AVFilterBufferRef picref)	239	static void start_frame(AVFilterLink link, AVFilterBufferRef picref)

scale: make the filter parametric

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