Make the init and config_filter callbacks of the pad filter return

AVERROR(EINVAL) rather than -1 in case of invalid parameters.

Originally committed as revision 23121 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/vf_pad.c

@@ -49,12 +49,12 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
         sscanf(args, "%d:%d:%d:%d:%s", &pad->w, &pad->h, &pad->x, &pad->y, color_string);
 
     if (av_parse_color(pad->color, color_string, ctx) < 0)
-        return -1;
+        return AVERROR(EINVAL);
 
     /* sanity check params */
     if (pad->w < 0 || pad->h < 0) {
         av_log(ctx, AV_LOG_ERROR, "Negative size values are not acceptable.\n");
-        return -1;
+        return AVERROR(EINVAL);
     }
 
     return 0;
@@ -178,7 +178,7 @@ static int config_input(AVFilterLink *inlink)
         av_log(ctx, AV_LOG_ERROR,
                "Input area %d:%d:%d:%d not within the padded area 0:0:%d:%d or zero-sized\n",
                pad->x, pad->y, pad->x + inlink->w, pad->y + inlink->h, pad->w, pad->h);
-        return -1;
+        return AVERROR(EINVAL);
     }
 
     return 0;