lavfi/curves: add support for Photoshop curves files (.acv).

doc/filters.texi

@@ -2346,6 +2346,8 @@ Set the key points for all components (not including master).
 Can be used in addition to the other key points component
 options. In this case, the unset component(s) will fallback on this
 @option{all} setting.
+@item psfile
+Specify a Photoshop curves file (@code{.asv}) to import the settings from.
 @end table
 
 To avoid some filtergraph syntax conflicts, each key points list need to be

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  56
-#define LIBAVFILTER_VERSION_MICRO 100
+#define LIBAVFILTER_VERSION_MICRO 101
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_curves.c

@@ -19,7 +19,10 @@
  */
 
 #include "libavutil/opt.h"
+#include "libavutil/bprint.h"
 #include "libavutil/eval.h"
+#include "libavutil/file.h"
+#include "libavutil/intreadwrite.h"
 #include "libavutil/avassert.h"
 #include "avfilter.h"
 #include "formats.h"
@@ -54,6 +57,7 @@ typedef struct {
     char *comp_points_str[NB_COMP + 1];
     char *comp_points_str_all;
     uint8_t graph[NB_COMP + 1][256];
+    char *psfile;
 } CurvesContext;
 
 #define OFFSET(x) offsetof(CurvesContext, x)
@@ -80,6 +84,7 @@ static const AVOption curves_options[] = {
     { "blue",  "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "b",     "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "all",   "set points coordinates for all components", OFFSET(comp_points_str_all), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
+    { "psfile", "set Photoshop curves file name", OFFSET(psfile), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { NULL }
 };
 
@@ -297,6 +302,60 @@ end:
     return ret;
 }
 
+static int parse_psfile(AVFilterContext *ctx, const char *fname)
+{
+    CurvesContext *curves = ctx->priv;
+    uint8_t *buf;
+    size_t size;
+    int i, ret, av_unused(version), nb_curves;
+    AVBPrint ptstr;
+    static const int comp_ids[] = {3, 0, 1, 2};
+
+    av_bprint_init(&ptstr, 0, AV_BPRINT_SIZE_AUTOMATIC);
+
+    ret = av_file_map(fname, &buf, &size, 0, NULL);
+    if (ret < 0)
+        return ret;
+
+#define READ16(dst) do {                \
+    if (size < 2)                       \
+        return AVERROR_INVALIDDATA;     \
+    dst = AV_RB16(buf);                 \
+    buf  += 2;                          \
+    size -= 2;                          \
+} while (0)
+
+    READ16(version);
+    READ16(nb_curves);
+    for (i = 0; i < FFMIN(nb_curves, FF_ARRAY_ELEMS(comp_ids)); i++) {
+        int nb_points, n;
+        av_bprint_clear(&ptstr);
+        READ16(nb_points);
+        for (n = 0; n < nb_points; n++) {
+            int y, x;
+            READ16(y);
+            READ16(x);
+            av_bprintf(&ptstr, "%f/%f ", x / 255., y / 255.);
+        }
+        if (*ptstr.str) {
+            char **pts = &curves->comp_points_str[comp_ids[i]];
+            if (!*pts) {
+                *pts = av_strdup(ptstr.str);
+                av_log(ctx, AV_LOG_DEBUG, "curves %d (intid=%d) [%d points]: [%s]\n",
+                       i, comp_ids[i], nb_points, *pts);
+                if (!*pts) {
+                    ret = AVERROR(ENOMEM);
+                    goto end;
+                }
+            }
+        }
+    }
+end:
+    av_bprint_finalize(&ptstr, NULL);
+    av_file_unmap(buf, size);
+    return ret;
+}
+
 static av_cold int init(AVFilterContext *ctx)
 {
     int i, j, ret;
@@ -317,6 +376,12 @@ static av_cold int init(AVFilterContext *ctx)
         }
     }
 
+    if (curves->psfile) {
+        ret = parse_psfile(ctx, curves->psfile);
+        if (ret < 0)
+            return ret;
+    }
+
     if (curves->preset != PRESET_NONE) {
 #define SET_COMP_IF_NOT_SET(n, name) do {                           \
     if (!pts[n] && curves_presets[curves->preset].name) {           \