static int process_command(AVFilterContext *ctx, const char *cmd, const char *args, char *res, int res_len, int flags) { OverlayContext *over = ctx->priv; int ret; if (!strcmp(cmd, "x")) ret = set_expr(&over->x_pexpr, args, ctx); else if (!strcmp(cmd, "y")) ret = set_expr(&over->y_pexpr, args, ctx); else if (!strcmp(cmd, "enable")) ret = set_expr(&over->enable_pexpr, args, ctx); else ret = AVERROR(ENOSYS); if (ret < 0) return ret; if (over->eval_mode == EVAL_MODE_INIT) { eval_expr(ctx, EVAL_ALL); av_log(ctx, AV_LOG_VERBOSE, "x:%f xi:%d y:%f yi:%d enable:%f\n", over->var_values[VAR_X], over->x, over->var_values[VAR_Y], over->y, over->enable); } return ret; }